Project: 98ton Expedition Submarine

Greetings Wilfried, Please allow me to introduce myself. My name is Robert ... I've been looking around for a father/son project (my father and me :-). And this seems right up our alley. I understand you've been considering a business to make c-subs. Have you considered selling plans (or kits) for c-subs? Neither me nor my father want to get into the business of making/selling/supporting any product (let alone c-subs). So if you were to sell us plans, we'd be happy to sign some agreement to that extent.

Cheers,
Robert

I have built a 20 ton prototype submarine yacht back in 1994 which performed very well in diving and yachting. As internet gives me a platform to show the proyect and find support and partners all over the world - i am now working on taking this to the next level.

The idea is to build the hulls of the submarine yachts here in colombia where labour cost is low i can supervise anything on a dayly base and finally ship the ballasted hull for final outfitting to the buyer. This is the most elegant and less expensive way to get a submarine yacht together.

I have a problem to sell you plans as the tricky part is not in drawing the lines - the tricky part is the practical part in the shipyard to form a perfect blimp shape out of concrete while keeping all the basic rules of concrete construction - which is the only way to guarantee a good final result. Which means a concrete hull that is as strong and long living as concrete can be in bridge foundations submarine tunnels or anywhere else.

So why not get a hull of some 60 -100 tons which is enough size to go on its own keel to california. When you have it parked there it will be big enough to keep anything on board while you fit it out in a father son proyect. There is no cost asociated if you do not work during a couple of months as you need no shipyard rental, no marina, just an anchorplace.

Let me hear your thoughts...kindest Regards Wilfried

Yes, this would be the basic calulation for a 60 ton displacement hull ready for shipment. This means hull ready and painted hatch in place, ballasted, provisorial or final viewports in place, - rudder working - shallow test dive on building site done with success.

The viewports is a calculation apart - if you go for no viewport - above is basicly all.

If you accept disc viewports of 5 cm acrylic sheet material some 50 cm diameter - as i had on my prototype - calculate some additional USD 200 per viewport.

If you want special viewports exclusivly meant for use in submarines you get basicly the same at 20 times the cost. [ NASA effect - if it is for space or submarine use a srewdriver is for 5000 USD ]

What concerns the diesel engine it makes sense to build the engine in - so shipment to california can be done on own keel - no tug boat needed .

If you go for the - with engine - configuration we would build in a diesel - but cost of the engine would be additional [ not included in hull calculation] - integration of diesel with boat [ 2 circuit cooling, propeller shaft, etc...] is part of the hull - so it is included.

Also included snorkel configuration - so boat can go with snorkel and do simple static dives in case of bad weather during shipment to california.

Not included are electro engines, battery, electronics, etc...

The reason i give you a price that low is because the best way to get the word out is to have submarine yachts working and running - atracting all this public attention in the yachting scene - so i calculate the first hulls directly on building cost - my profit is the promotional value of a submarine yacht working and diving.

Limitations are the cost at marinas, - as you generally pay for boatlenght. The good thing is that, at difference to surface ships which need harbours for security reasons a submarine is completly safe on an anchorplace. No weather and no burgler can affect it. On the anchorplace size is no problem.
If you want to slip it, weight becomes an issue - even a small boat of 60 tons is out of limit for the cranes that are used in normal weekend boat yachting scene. Using a mega crane and bigship instalations is expensive. The advantage is, that you never have to take a concrete hull out of the water, which means a lot of money in slip cost. It is like bridge foundations or submarine tunnels - those are not meant to come out of the water each season to get a new paint and repair fouling and corrosion damage. Once in the water they stay there for the next 100 years - at least - concrete gives you this advantage.

To get an idea of the right size take a couple of plastic sheets and cover a space roughly the size you have in mind - think that at least 1/3 of the space will be occupied by ballast tanks, and machinery - this exercise will give you a good idea how living and working conditions in the hull will be, and how interior design can be distributed. Keep in mind that in a sailing yacht you have space on deck - this is not the case in a submarine. So i think some 60 tons is smallest size suitable for yachting style trips.

Tow - ability is not a problem - the force required to tow and move a streamline shaped submarine hull is very small calculate 0.1 kilopond force per ton - speed is limited by the displacement hull formula - the more length the more speed.

I would prefer a sub without any viewports. Using an underwater camera makes sense. Does omitting the viewports increase it dive depth?

Yes, big viewports limit dive depth to 100 meters the hull itself might reach at least 600m and have a destruction depth well below 1000m. [ http://concretesubmarine.com/ ]

My father was a diesel mechanic, so I suspect we'd want to build our own engine. So if we buy a boat with out an engine, we would have to tow it to CA, right?

It will probably be cheaper to build a used provisorial diesel in and go to california on own keel than renting a tow boat with crew for this trip. Refurbished diesels are cheap and work fine - you can replace the engine in california with a more sophisticated final solution.

What are your engine options (size, power, range, ...) and your recommendations?

On my prototype i found that i could manouver perfectly with a 200W electric engine under storm conditions. This would be a absolutly ridicoulous power source for a similar sized sailing or motor yacht - you never could get your bow into the wind. The reason is obviously that a sub with its hull below water level just does not catch any wind no matter how bad the surface conditions are. So my conclusion is - you do not need a big engine for safety reasons to get you to a save port in front of a storm, push you trough a pass to reach a save bay etc...what you need is a engine to get you to top speed of a displacement hull. There is very little power required to do so - this is why engineers consider submarine tankers and whales do travel thousands of miles whithout feeding - very little energy is required to move a streamlined body under water. On a 60 ton submarine 20 horsepower may already be oversized. Well you will not get a very small diesel that runs culivated, silently, and is suitable for thousands of hours of running time in a highly efficient manner. But my recomendation is - get one of the smallest you can get and get a by far smaller one you would look for a similar sized yacht and - most of all - forget the 2-3 horspower/ton recomended for sailing and motor yachts. Look for a small watercooled diesel from a generator or a similar application.
Range is basicly limited by tank size - you can easyly get half of your ballast as tank space which means for a 60 tonner some 15.000 liter tank capacity - you understand how german ww2 submarines could go to the golf of mexico which meant 2 atlantic crossings per mission - no tank stop included...no other boat has such a tank capacity and range as a submarine. Surface boats have to watch floating line this limits tank and loading capacity.

Is the boat compressed O2 capable? I understand its not required for short dives, but required for longer dives. How long can the boat dive (with two aboard) before it needs to surface for fresh air.

This is the basic math about breathing in submarines: A person takes about 2liter of air per breath 6 breath a minute. A 60 tonner contains some 60.000 liter - you can breath the same air at least twice - this gives you some 120.000 breath cycles after you close your snorkel without any air treatment. So we are talking of many, many, hours of divetime depending on how many persons are breathing how rapidly they breath etc... So we are speaking of by far more than 24 hours of divetime without any air treatment [ calculate 8600 breath cyles per per person for 24 hours] - After this - what becomes critical [after breathing the same air several times] is not lack of oxigen but the raise of CO2 level which first gives you a headache finally makes you pass out slowly. So what you need to do is open a sack of chemicals that absob CO2 . While CO2 is absorbed into the chemical the pressure in the boat is falling a little bit - you can mesure it with a simple barometer . You now replace the same gas volume that formerly was occupied by the CO2 with oxigen from a medic use oxigen bottle - just open the tank valve until barometer needle returns to the same place it was before you uncovered the absoption chemical. Your athomosphere is new- headache away - breath again many many hours...so in practice you will not need air treament except in case of emergency - you can breath days with no air treatment in a yacht size submarine with a small crew.

On the other hand - In a small boat with a few liter of athmosphere this process is vital as things become critical within a few minutes in a boat that contains a few liter of breathable athmosphere. A small sub has also limited space to store oxigen bottles and chemicals. With a few kilos of chemicals and a couple of of small oxigen bottles many of those boats offer a maximum of 2-3 days stay alive in emergency case. In a 60 tonner you can store sacks of chemicals and a hospital size oxigen supply for literally weeks of submerged survival time. Those pictures we all have in mind from submarine crews runnig out of air, are only true for military submarines where you have a crew density of about 1 man per 1m2 living space. There is a lot of breathing going on if you have a crew of 100 men in rapid breathing stress conditions in a sub where 90% of the sub is flooded and the crew is mounted in one small compartment- exampel KURSK if you do not get them out in a few days...

Sounds like a good strategy.

On size/displacement/towing ... how *small* can you make a one-man sub? A two-man sub? Can it be small enough to be towed (out of the water)?

I like the idea of getting a fully functional sub from you (putting it in the water off Columbia and navigating it to California under its own control). Maybe you could specify the details.

I'm thinking that starting with a small sub initially might make sense and then buy a bigger (and more expensive) sub later after I have a year or so of experience. This will let me build an ideal
bigger submarine. You mention both an diesel engine and an electric engine. Do you recommend both?

So if you think in system cost - submarine + handling - you will find that a smaller boat is more expensive due to its need to come out of water after dive.

My basic idea was to come up with a autonomous submarine that can work like a yacht with stay aboard quality and bouy as only infrastructure needed.

For this a 20 tonner is minimum - but still not spacy enough to go on own keel overseas - lack of live aboard quality - minimum for a seagoing vessel is 40-60 tons.

OK, then lets keep talking about 60 tonner. I'm sure you've already seen this, but in case not ...http://www.physorg.com/news3985.html

I'm quite serious about purchasing a sub. I've been considering buying a sailboat (after learning to sail :-), but a sub seems more to my liking. My goal is to be able to visit very remote locations in the world. In many cases uninhabited lands (or at least uncivilized lands :-). I'm a bit of an expert in wilderness survival and I'd like to experience other parts of the world (the "wild" parts :-).So my questions will be about a "day in the life" of a sub-mariner aboard a sub built by you. See what I mean? Does this make sense?

For example, you mention both a diesel engine and an electric engine. Is the diesel engine just to charge the batteries for the electric motor (which turns the screw)? If so, how much charging (time/fuel) does it take to charge the batteries from empty to full? How far can the sub travel on fully charged batteries? Have you ever
considered solar charging of the batteries?

I've begun looking into slip locations/fees. What is closest to me is harbors in the San Francisco Bay. But I'm not sure they are best for a sub. It (because of how low in the water it sits) might require a "harbor pilot" to get it under the the Golden Gate bridge and out to sea.

Once we determine the size and configuration of the sub, I'll send you the appropriate down payment. What percentage would you require up front? Also, if I fly to Columbia to take delivery, would you be able (willing :-) to spend some time bringing me up to speed?

Some of the reading I've been doing on c-subs suggests that they are not buoyant; that in order to stay on the surface they need to be constantly propelling themselves up ward. Is this accurate?

I've been thinking more about a c-sub and the San Francisco Bay Area. Are you familiar with the Bay Area and specifically Silicon Valley? The residents here (on average) have a lot of disposable income. And the greater Bay Area is quite nautically oriented.

You might want to spend some time here (after you build my sub :-) with my sub showing it off to people, organizations, ...

This is really an ideal location to promote submarine yachting. :-)

Thoughts?

So concrete structures can float or sink depends on this ratio - the hull of my prototype was designed to a weight of half of displacement. If you check the pictures at - www.concretesubmarine.com - you see it floating on this line during crane operation. Loaded with ballast, outfit, and machinery which sum a total of 10 tons it is neutral buoyant - as any normal submarine.

In fact those articles about military c-subs suggest a dynamic concept similar as deepflight - just reverse - which for my understanding is nonsense for security reasons - so i think those people which wrote this article did not understand the concept properly...

...bendable concrete
what you need for a submarine hull is exactly the contrary to "bendable". The walls bending in under water pressure is last thing you want to have. So this is interesting - but for other applications. In submarine building the materials are hardened steel with low flexibility, glass spheres, and similar ...what you need is, that material keeps its form under pressure until it reaches failure point - exactly this is what normal concrete does.
The other thing is that in a submarine you should avoid experimental materials as you want a predictable result that will not fail surprisingly and far from the calculated failing point.

- visit remote locations -
As expedition vehicle a submarine is excellent for 3 reasons. First load capacity - you can replace ballast with supplies, and tanks - so in case of a 60 tonner you have 30 tons load capacity - which gives you tremendous autonomy for many months - a similar sized sailing yacht would have a load capacity of less than a quarter of this. Second - leave alone capacity - you can leave a sub on the anchor place, close the hatch, and leave it alone for months it is as safe as a bunker - you would not do that with a sailing yacht if you have seen what a burglar, pirate, sea lion, bear, can do with a sailing yacht in a few minutes. Third, survival capacity - in a sub you will survive and even enjoy ANY weather condition including hurricanes. I had a good spectrum of conditions at my test site from ice cover in winter to tropical conditions in summer and violent storms the prototype performed excellent in all of those conditions.

-day in the life of a sub owner compared to yacht owner

I see you are familiar with yachting especially sailing yachts. - So i asume you are interested in what is different in a sub yachting day compared to a sailing yachting day.
First event of the day both the subber and the sailor row out to anchor place in a dinghi and board their vessels - the yacht is full of bird shit so the sailor starts with cleaning his deck - the deck of the subber is clean as the waves do this job. The yachty also has to perform a couple of repair jobs in mast, sails, lines due to UV light, wind, etc... Finally both open their hatches - the yachty gets a blast of 60 degree celsius hot air - stinky - product of heating of the teak deck from sunshine. The subber gets fresh cool air - product of a hull cooled by surrounding sea water. So the yachty stays on deck to wait for air circulation trough the hatches to make the interior of his ship bearable. The subber goes down trough the hatch in his "blue saloon" light comes in trough the viewports which with 50 cm diameter are bigger than windows you would find on a standard yacht so interior gets more light than you would have in the belly of a sailing yacht, as light goes trough water before it reaches the interior of the sub the effect is like in famous "gruta azul" in italia.
The yachtman may find things under deck a bit shaken, everything - on the floor, liquids spilled around, product of the last storm the yacht suffered on anchor place. The subber will find anything on its place even if things was not properly stored away at end of last trip. This is because the sub did not move in waves and if there are any movements they are very gently almost imperceptible.
Both vessels will leave anchorplace for a trip. While the yachtman has to store anything away before he passes the breakwater the subber leaves the coffee cup on the table even in rough weather. He will open a valve and take some 300 liter of water into the ballast tank so the water will cover the hatch and only thing above surface is a pair of snorkels. In this condition the boat runs with diesel engine. In a sailing yacht the noise level under deck when diesel is running may be very loud. Sound dampening is most of all a product of the weight of the walls - bad news for sailing yachts where the walls are made of light and thin material. - the subber is separated from the engine by a heavy concrete wall of 10cm so noise factor is much better. The sailor will enjoy sun, rain, wind, nature, the subber will get a view of the underwater world see fish. He might stop the diesel and close the snorkels to take up a few liter more of ballast water to dive down to the seaflor installing the boat a meter or two above the bottom in a neutral trim so currents will give a free underwater voyage making seafloor slowly pass in front of the viewports. You can stay down for hours without using battery power. At the end of the day the sailor will head for a secure port or anchor site running trough bad weather to make it before nightfall, risking his boat, depending on exact navigation. The subber will simply go asleep where he is - a save port is anywhere - just go to snorkel depth or lay the sub on sea floor during a quiet night sleep. After trip the clear up the ship is much easier on a sub- just close hatch drop anchor - ready - no spray hood, no storing away - a sailing yacht always must be prepared to stand the worst possible weather condition - alone on anchorplace - for a sub even on anchorplace weather is meaningless.

-
Engine configuration

On my prototype i had a electric engine as main engine that was powered by a relativly small set of lead batteries which where recharged by a small hand generator. For a oceangoing submarine with emphasis in long expedition trips a diesel direct configuration may be better due to less loss in power conversion. Recharge of batteries as long as we talk of normal batteries is 10 hours for a full reload. How much time you can run under electric power obviously depends on battery and electric motor size. I had a configuration of about 2 hours runtime with a full battery load.

- Solar power
When i configurated my e-engine solar cells where expensive so no real option - this may be different by now - i also considered wind and stream generators - but both factors where not very favorable at my test site. So i ended up with the most simple - recharge by generator. Any how you do not need to determinate the configuration. Most simple is to build hull - put a simple diesel in so you can move it - later you will test out the configuration that fits best to your needs. This is part of the fun...

- Slip locations fees
The idea is that a concrete hull will not need slip nor harbor location for decades. So as a sub owner you should think a little different to yacht owners which are alway in search for a safe place with surveillance in a harbour or a marina. I am not very familiar with your area but i think there is a coastal road... So i would take a trip along this road and check that secondary accesses to the small bays where only a handful of people live. Put a buoy in one of those bays and hang the sub there this is all you need. It should be free or at least very economic to park your sub in such a place far from metropolitan areas and ship traffic.

- determine size
I will come up with a couple of drawings for a 60 tonner to have a better base to talk - just give me a week or so...

- percentage to start
As usual in yacht construction we need 50% of the hull cost upfront as cost of materials and building site must be covered at starting phase. To give you peace of mind about the project i will keep you informed of building status during the process by digital photos and reports.

- hand over
Of course the hand over will not only include testing but also a couple of trips down here to make sure that the long trip up to California will be without surprises. If you find the time to come to Colombia to be part of this and learn about handling you are most welcome. You can take over the boat here in the Caribbean or agree a shipment to California as part of the testing. I am offering both options. I assume this depends on your time table. The closer you can get involved here in Colombia the better for me as it takes the guesswork out of my job.

For me, the more the sub can be shown around - the better. The more you want to have me aboard the better. Each entrance in a harbor is a event to get the word spread.

I've been thinking about how to "hide" the submarine (to prevent piracy/theft when at remote locations). One idea is to have it fully submersed (only a couple of meters below the surface) with an external lever exposed to raise it. Then I would have to dive in (swim down a couple of meters) and flip the lever and wait for the sub to surface.

What is used to secure the hatch? Do you use simple padlocks, or ...?

You are right - on the anchorplace somebody could cut the anchorline and tow the sub away - all tough you can take measures to make this task difficult. If you use chain to anchor and hide the chain and winch on deck so somebody still could dive with a underwater soldering equipment and cut the chain under water - but how likely is that this will happen ? In any case security is several times better than any yacht where a light hand tool is all you need to steal the ship.

The security of the hatch is very good as the hatch is designed to withstand tons of water pressure its nature is similar as the door of a bank safe. If you get it locked from inside breaking in needs formidable heavy equipment it also needs mayor logistics to deploy at the anchor place you can easily make it unbreakable with very little additional effort if needed.

Of course the ultimate security is to hide the sub under water. To perform this it is not even necessary to swim down for recovery. I experimented with a garden host and a zodiak hand pump. The host goes into a caisson saddle tank that can receive air. When you go ashore with your zodiak you deploy the host and take the pump with you - you need it anyhow to pump up your zodiak when returning. Pump some air trough the host down to the submarines saddle tank - 5 pump moves will make the submarine resurface . Pump in hundred liter to get stable flotation then pump up the zodiak you are ready to board without getting your feet wet. The depth limit for underwater parking is the pressure limit of the hand pump i tested to some 10m this works just fine. Similar works a line that opens a package of baking soda producing gas for resurfacing.

The problem with storing the sub under water is that you have no ventilation in the sub and this brings us to moister build up problem.
In general when experienced yaching people buy a yacht first thing they do is having a look at the deepest point of the hull which is the bilge - if it is completely dry you have a good boat if there are a couple of galons of water down there you have a problematic boat.
If the water is saltwater you have a leak that needs attention if it is less salty you have a condensation problem. In general terms the hulls i deliver are boats with a completely dry bilge. Which means they do not have seeping leaks nor condensation problems.

Condensation takes place when air charged with high humidity comes in contact with cold surfaces - air cools down and cold air can hold less humidity so small drops of water condensate on the cold surface. In a yacht you have normally hot sticky humid air and you have a part of the boat under waterline where the hull is relatively cold - this causes condensation moister, rotting, fungi and all kind of problems.
This is why yachts generally have insulation made out of pu-foam which is glued directly on the hull surface and avoids temperature leaps that produce the problem.
The second way to avoid moisture is to avoid that air in the boat gets saturated with humidity which can condensate. This is where ventilation comes in. If you constantly ventilate the boat air never reaches a grade of humidity that permits condensation. This is why in yaching talks solar ventilators, ventilation on anchor site, etc is a never ending theme. Quality of life aboard depends on it.

One of the few things that really surprised me during testing my prototype was the complete lack of moister. In fact i was prepared to test out several types of insulation and ventilation during the test period. My expectation was that the moister and condensation problem would be at least so bad as it is in a steel yacht - probably worse. Nothing of that happened. Although i had no insulation at all the walls always stayed dry without condensation during all possible weather conditions from winter ice to summer heat.

I contribute this fact to two factors. First the hull as it is almost completlyunder water does not have hot or cold parts and the air temperature and the wall temperature are always exactly the same. So if there is humidity there is no surface to condensate.

Second the prototype had a 2 snorkel configuration the front snorkel had a plastic cone to take air in. As the sub always tends to put the nose into the wind on the anchor place there is always a pressure difference between front and aft snorkel which makes air enter in front snorkel and leave the boat trough aft snorkel after circulating almost the whole boat length. Having in mind the length and narrowness of those snorkels and also the fact that air takes 3 90 degree turns i expected very little natural ventilation. But in contrary the air stream was clearly noticeable and by far stronger than expected. I assume that this has to do with the hermetic closure of the hull which leaves only one defined ventilation pass.

All in all i ended up with a very dry, very ventilated boat without any additional measures - not expected in first place - but finally a fact under all weather conditions and over years of use.

This brings us back to underwater parking. I can not guarantee that this dry boat scenario will happen if you close snorkels and park the boat under water. The temperature factor will remain but ventilation will fail. Obviously you could dry the air with silica gel. Anyhow i can not give you a good answer what happens if you park the boat 5 months without ventilation - would electronics still work ? Would you get a dry atmosphere like a coffee vacuum pack or a wet atmosphere like a bat cave - honestly i did not test it and can not answer it. All i can say is on anchor place with 2 snorkel configuration you get a dry boat.

Hand generator.
No - what i refer as a hand generator is one of those small auxiliary generators with combustion engine and generator in a integrated pack with a handle so that a single person can move that thing without a crane. My test site had very strict ambient rules that limited yachts to electric engines. So i had a official electric engine with battery and was registered as electric boat. When i came for a yachting day i brought my generator connected its exhaust to the aft snorkel and had unlimited range as the electric engine was not powered by the battery but by the generator and the combustion engine. Of course this chain diesel, generator, UPS, electric engine, screw has losses in any step - which means nothing if you do day trips - but cost a lot of money if you do ocean crossings.

Diesel only
Lead battery sucks...not only they need 10 hours to get a full reload, they also have low energy density, high weight, and living time of maximum 3 years. Some of the nasties submarine accidents in history where caused by flooded batteries producing chlor gas. So if you can´t avoid them completely keep the pack as small as possible. Of course you could lithium ion, fuel cell etc... But honestly how much electric engine power do you really need. This question is different for a military sub that must get away - unseen no snorkel - as fast as possible. But a yacht submarine why would you need to move the boat under water anyhow? If you are a scuba diver you will know that the only diver that swims around under water is the freshman... As a experienced diver you go down stay on the place quietly and let submarine life come to check you out. Freshman swimming around and making noise will not see any fish...
If there is a current - and in 95% of cases there is some - let the current do the work just hang out and let you take away - if there is a lot of current they call it drift dive. The key is that the boat drops you that way that the current brings you right along the interesting places if the dive point is selected carefully there is no need to paddle around using your engine (legs).

In scuba diving coming up getting a ride with the dinghis combustion engine diving again is hard work. In a sub you can go up to move counter current with combustion engine go down to drift dive again much easier and completly effortless. You even can combine this with a GPS to make a search grid. Get a starting point go down let you take a mile with the current to inspect ocean floor get a end point. Go up return to start point under diesel start a parallel strip. Your diesel brings you to any point in the sea and the current gives you free underwater rides . Ben Franklin did a 1200 miles trip underwater with golf current with no engine use in a single dive.

So yes, diesel only is not only possible it is a good option due to safety and ease of use. Have batteries for lights, computer. Limit engine use to surface and snorkel depth where you can use diesel. You also can extend snorkel depth by extending snorkel by hosts it will be practical to some 20m of depth.

In any case exhaust gases must be strictly separated from passenger compartment in my prototype i had a pressure gradient between engine room and passenger compartment. When diesel went off i kept ventilating engine room trough aft snorkel at least 3times to expulse any rest of exhaust gas before diving. There was also a hermetic door between both compartments.

-3 visits to colombia -The more the better -

You suggested the diesel direct for long expeditions. It seems that a rechargeable battery driven system would have (theoretically) infinite range. But there is often a big difference between theory and practice.

Would you mind outlining the plusses and minuses (or if you prefer the pros and the cons :-) of diesel vs electric?

Load capacity of the 60 tonner is 30 tons take some 15 tons for expedition gear, water, machinery, leaves you 15 tons for diesel which gives you some 15.000 cruising hours and a range of 30.000-90.000 miles without refueling - probably much more than you ever need. The physics behind that makes those journeys of a humpback whale without feeding for months possible. Basicly you can move a streamlined heavy body submerged over enormous distances at moderate speed with very low energy use.

Compared with a motor yacht a submarine holds a enormous range advantage due to its superior tank capacity and more economic displacement as it avoids wave resistance.

What are the (approximate) overall dimensions of a 60 tonner: length, width, and hull thickness? Is it (approximately) an 4x1 ellipse (or some other ratio)?

It seems that it might make sense to install a (flat) floor under which is storage. The largest (but least practical) floor size would be across the middle. The smallest size (of course) approaches zero and is also not practical. :-) Is there an ideal ratio of underfloor volume to floor surface area? I know this is a personal preference, but I suspect you've thought about this.

I am not so sure how many tons a final vessel would have, it is only my general idea that you would need something with at least 3 times the inner space that my prototype had to get something like a capacity to store expedition gear, food cooking and sleeping during a couple of weeks as required for ocean crossings and expedition like trips.

The best way to figure it out is to leave apart for a moment the submarine and think in detail about the question: If i had to live in a confined space for x time and, had to store all the necessary things in this space i could not leave - what size must that space have to make it bearable, comfortable - are we talking about the size of a minivan - probably not - a big bus or a container size - more likely.

Keep also in mind that large volumes of your space will be occupied by things like the engine room, freshwater and diesel tanks. A toilet, a shower, cooking facility, bed, etc...

Keep also in mind that in a submarine only the ballast (if you choose the cheap version sand) will occupy 1/3 of the space inside the hull. If you decide to change all ballast with diesel tanks those will occupy at least 2/3 of inner space as diesel weights less than sand so this is not very practical and you will opt for less range and more living space. You could also change part of the sand with lead bars so this would increase ballast material cost but also reduce space occupied by ballast . Or you may opt for a bigger boat and stay with sand ballast to get same living space.

What concerns distribution on my prototype the first configuration was with simple wood interior with seats at the viewports and a small walking space with 2m height in the middle . Engine room was separated by a wooden wall. Later i thought that it might be spacier to distribute ballast in the floor area and it also would be better to have a concrete wall to dampen engine noise.
So i ended up with the flat floor configuration you have in mind. As i said in this configuration you end up with ballast covering roughly a third of the hulls bottom section. I prefer this configuration due to spacey feeling ease to build and stability due to optimized ballast distribution.

But be aware there is no store room beneath floor at all as this room is packed with ballast.

What concerns general construction rules we should keep the length/diameter ration of the prototype as this seems to have sufficient stability during static dives and in case of partial flooding i am quite sure that such a hull will stay on even keel . So keep length diameter ratio 2,5 / 10 .

So to get a final displacement check the space needed for living add 1/3 for ballast add more space for a decent engine room where you can reach the important parts of the engine and also be prepared for mayor repair operations without going nuts in the process and folding yourself in anatomic impossible angles.

Doing a rough basic calculation on base of ellipse, cylinder etc.. Is a good idea for a approximation. Doing a full size model of the space with a main frame and a rough streamline shape is also a good and cheap way to get a feeling for the final available space.

Just keep the length diameter ratio - how exactly the form thins out on the ends is of little importance and mainly a style question avoid very long thin ends as those spaces are not useful.

Doing a test in a carton box you will find that having a bathroom of 1x1 m or 1,5x1,5 will make a world of difference in living quality.

I would prefer if you could give me first a length / diameter ratio you would be comfortable with - based on space test in a mock up - i then would come up with a drawing and proceed to a drawing as base for a building plan.

Use plastic, paper and wood in 1:1 models to test out spaces before proceeding in drawing and building a vessel is a common exercise in mayor shipyards.

The more you test it out- the more the final submarine will satisfy your needs. A final displacement number is something that comes up relatively late in this preliminary process where needs and sizes are fixed.

So what i try to explain is that the size and dimensions is something you should figure out in your backyard with a model that looks ridiculous but you probably can sell to your neighbor as a greenhouse or so to avoid to be declared completely nuts... This gives you a by far better idea of reality in the sub than drawings.

From this we would establish a kind of frame table where the diameter from length axis is fixed every 50 cm - it would be great if you could give me that table to determine the final shape. But i also will be happy if you only give me mainframe diameter and total length of the boat - so i simply will determine shape by following a nice streamline body.

The question - what will fit my needs - is a question i can not answer for you. I can build you any boat - any size . I also can orient you not to forget the spaces necessary for ballast etc... to avoid - oh i did not think about that... situations - but the final decision is yours.

Take away 1/3 of the space for ballast, take away the volumes of tanks, so you end up with half a container, from this take away a wall thickness of at least 20 cm, then take away a third of the left space for an engine room. This gives you something in the size of the load area of a small truck to live in and store your expedition gear...so i agree completly the size of a container may not be enough for a long range expedition vessel with live aboard quality you have in mind. Maybe 2 container size is more indicated - so we are already speaking of a 160 tonner - far away from the 60 tonner we had in mind ... On the other hand material cost is not so overwhelming if you build in concrete. Also ship size does does mean little in a anchor bay. The bright site is - in a space the size of 2 containers, you can move and live during outfitting, set up a reasonable work area etc...which makes you independent from hotel rooms, material storage sites, land infrastructure. Which spares a lot of money. Real independence comes only with a certain boat size.

Hello Robert,

To fit into a container the mainframe diameter has to be limited to 2,5m which would be exactly the size of my prototype - this is by far to small for a expedition boat. I think we should just forget the idea of transporting a equipped sub over land as it would not fit in weight even if it would fit in size.

Yes there exist experiments to confinement. One of those was Ben Franklin it had a mainframe diameter of 3,15 m (10feet) to fit in 2 pieces in european railway measures. Total displacement was 130 tons, Ballast was lead batteries it made a 2700 kilometer drift yourney in golfstream 1969 with 4 crewmembers. This was more or less survival minimum considered by grumman airospace.

So a blimp shape with 9.77 feet cross section would be a by far smaller boat for maybe 1-2 crew for trips of maximum a week or so.
A ocean crossing in such a boat may be more a survival experience than a yachting experience due to extreme confinement.

Another confinement was sealab 2 which had cylinder shape 13 feet diameter 57 feet long, and was used for confinement experiments of 15 - 30 days - which would come close to ocean crossing.

In a blimp shape standing height is not so problematic you have standing height in any boat above 20 tons . Lack of space is biggest issue. My prototype was very spacy while it was an empty hull, but it came down to minivan format due to ballast, engine, and tanks.

Using lead ballast is not so good as the cost of lead bars to make space in a smaller boat is higher than the cost of a bigger hull. So if you go for most space for best price go for a bigger hull and fill with sandballast.

A 9,77 feet cross section may look quite spacy when it is not divided in ballast and living space - so it is important to do this division in your mokup to get a realistic impression of the available space.

My general idea was something of about 15 feet as a minimum...

This would give a inner space of 11,9 feet height in main cross section. The man in the drawings is 6,2 feet high.

So this concept would allow a central idle with standing height for even a tall man in almost all of the boatlenght. It would give you "pockets" of space on both sides of the central idle where you can place things like beds, kitchen block, WC, Shower, and a table to sit without blocking the idle. Store space must be made in those lateral space pockets under the bed, kitchen block, etc. There may be a bit additional space under the floor if we get the sand heavy and tight packed but this will be reserved for tanks i assume. Space in the ceiling may be similar designed and sized as known from airplane handluggage store.

All in all this is not more than a container size of living space, but it would be able to do an ocean crossing with a small crew.

This is a little different from the 4:1 ratio (10:2,5), but I assume that the 4:1 ratio is really an estimate based on your prototype.

Is lead really that much more expensive? It seems like the densest material. Let me chew on this and get back to you.

I'm thinking of going with diesel-electric propulsion of your design & configuration (& construction :-). Originally I was thinking that the propulsion would be a fun father/son project. But I now think
the work should be limited to outfitting the interior. So getting a fully equipped (but barren) sub from you is now the plan. I assume this includes the diesel engine, the generator, and the batteries.

Also, could you include the fuel tanks in both the drawings and the sub? I assume the fuel inlet is just inside the hatch?

As you want the sub to perform in long expedition trips i made it as long and thin as i would feel comfortable with to maximize cruising speed. Ratio can be twisted a bit.

What concerns machinery my preferred scenario is - as little as possible - i would prefer a provisorial diesel only configuration - just enough to to sea trials and ship the sub to California - but if you plan electric too we can plan space in engine room for generator, electric engine, etc.../ the machinery is more expensive in colombia than in united states if your father is expert in diesels he will have his own plan which engine is best. Anyhow in a sub you will not connect the screw with its shaft directly to the engine because vibration of the shaft will cause sipping in the packing. So you have a flexible element between shaft and engine which makes it easy to disconnect and replace engine from screw and shaft.

So i would say i put a rather simple cheap, used diesel from a tractor or a construction machine in - just to be able to do sea trials and shipment to California - in California you take this diesel out and replace it with a real cultivated high tec diesel you can feel good with at ocean crossings- we also can keep that original diesel as backup which can go on shaft with a few minutes of mechanics if necessary. The shaft will be an independent element it can even be changed without taking boat out of water so the possibilities to re do engine configuration on anchor place are not limited.

The exact site of the division wall between engine room and living space depends on your preference. In yachting there is a tendency to put the engine in a small space where it can not be serviced - this is to maximize living space which is the selling argument.

In my sub i would make the engine room quite big, not only with space for engine and service but also with space for a working table with some basic machine tools to perform mayor repair operations because repair things is probably the most important activity you do on expeditions.

We do not need to decide final division at this point as we can maintain the hull undivided and ship it to california with a provisorial division. What concerns ballast and fuel tanks the space below floor level has to be divided into cells of not more than 1,5 m distance between cell walls. This is necessary to keep ballast and tank content in place. Most of those cells will be filled with ballast, some will be used as tanks. Heavy content like ballast in the center of the boat - light content in the ends. In the first configuration most cells will be filled with sand leaving a minimum of a ton or so for fuel and a ton for water. Later you can replace the sand in some cells with heavy lead or iron and fill the neighboring cells with light fuel maintaining the buoyancy as it is. In general you can configurate those cells as convenient for you. We do not need to decide tank ballast division at this point as any cell will be able to work as tank or ballast or store container with very little modification.

For a expedition you might decide to pull sand out of one cell and fill it with a ton on corned beef instead. Or you might convert a cell into a cold store or whatever. In general the top of the cells will be closed by the concrete floor, but you can smash a piece of floor which will only have 3cm thickness with a hand hammer to put in access hatches.

So yes, this is the best and most flexible configuration - you get a barren hull with a cell structure in the ballast area and a flat floor you can step on but you can easily modificate on top of all cells. All divisions modifications, interior and engine configurations can be performed on anchorplace.

> In my sub i would make the engine room quite big,

I agree with you bias here. Being able to service the engine is very important. So I'd be tempted (as you were) to make the engine room "roomy". It seems that it could also double as storage (that can be removed if/when the engine needs to be serviced. So making it roomy would not be a net loss of space.

> hull undivided and ship it to california with a provisorial division. - But I thought you would create a concrete divider so then engine would be less noisy in the living quarters?

my rough calculations are: water = about 62.2 lbs per cubit foot (at about 70 degrees F)= approx 32 cubic feet = 1 ton desiel fuel = approx 306 gallons per metric ton = approx 277 gallons = 1 ton = approx 37 cubic feet = 1 ton Sound (about) right?

> a ton on corned beef instead. - Now that's an image! :-)

You want to make the flat floor out of concrete? I thought the floor (since it needs to be highly flexible in its configuration) should be made out of wood (or plastic or ...). I guess it will be easier to visualize this once you finish the drawings.

. So i asume we should go with a series of different drawings to visualize different aspects of the boat...

Concrete divider. In my Prototype as you see in the interior foto i had first a configuration of pinewood with the engine room divider made out of the same material. I later took out the pinewood interior and went with that configuration of sand ballast in deepest point of the hull, a flat floor on top of the sand ballast and a 10 cm thick concrete divider to dampen engine room noise. Noise dampening is more than any a function of wall thickness and weight. Beside noise dampening the divider has a gas handling function. Although the exhaust of the diesel goes outside you might sooner or later get a leak that brings little quantities of exhaust gas into the ship which is a problem. The solution is to have a extract ventilator on your aft snorkel which produces light under pressure in engine room. So there is a steady ventilation from living area to engine room never on contrary. The function of the divider is to reduce the openings between living space and engine room so you have a relatively sharp air flow trough controlled and seal able openings. While you build in your engine this divider is not so useful. You would prefer to work on a barren flat floor until anything is in place and put the wall in later. We can go for sea trials without having that divider, for shipment to california we can lift up a proviso rial light wall that allows gas handling but can easily be removed. So when your dad has finished the engine part without being limited by the divider you lift up the final divider.

Water density is exactly 1 which means a cube of 1m side lenght (1000 liter) weights 1 ton. Diesel is a little bit lighter some = 0.8 - so you get 800 kilo as weight for a 1000 liter tank. Lead will give you 11 tons in the same space. Sand around 3 tons per cubic meter...

To visualize the space below the flat floor keep in mind that this will be divided in spaces of not more than 1,5m long and 1,5m wide which is about the size of a telephone cell. The walls of those compartments will have 3 cm thickness with a steelbar grid of 4mm bars in 10cm distance. Any compartment will have 1,5m x 1,5m. Their function is to hold ballast and liqids in place, they also support the floor from below. Each of those compartments is hermetic closed so it can work as ballast chamber, fuel tanks, water ballast cell, store, whatever. What you see as floor of your living area is the top side of those compartments. As your floor is supported every 1,5 m from the compartment walls below there is no need to make it very thick. It stays 3 cm with steelbars the same make as the compartment walls. The idea is to make the compartment walls and floor strong enough to hold things in place but also thin enough that they can easily be modified. So you can smash the concrete away with a handhammer with little effort similar as you would do in a brick wall solder a access hatch into the remaining steelbar net, redo the concrete around the hatch and have a store the size of a telephone cell inside. Which compartments are permanently sealed off as tanks, sand ballast compartments or accessible over hatches must not be fixed in basic planes. It can be decided and modified depending on your interior distribution.

So yes, you will have a flat concrete floor - but you can still have a wood floor on top of it maybe only a few milimeter thick parkett as in your living room.

In fact reconfigurate a concrete panel compartment is by far easier and quicker than one made out of wood or steel. It is hermetic and liquid prove almost by nature like the flower pot or an antique amphora - this would not be the case if one compartment wall is made out of wood.

Anyhow if you are absolutely not comfortable with a concrete floor we can lift the compartment walls only to a height that is necessary for ballast fixation and leave the compartments open on top so that you can put a wood floor on top of them. As we can avoid weather extremes i am sure that we can avoid going overhead during the trip to california so top cover of the compartments is not a primary security need it would only be a cheap and practical way to get a hermetic floor, tank, store and ballast fixation capacity in one construction process.