Submersible Sailboat?

I hope there aren't too many personal subs made. How will we avoid collisions?

 

here is "semi submersible" that might be starting point.

If nothing else, I bet it could sail up wind pretty well if you stuck a sail on it. Not sure if it carries batteries for diving, but looks like it could. I'd call it a "SWAMH" for 'mono' instead of 'twin'

Some of the benefits of SWATH without the double drag of extra hull's surface.

Sure must have been an interesting ride at speed.






HYBRID SUBMARINE-TORPEDO BOAT​

(1938-1941)

By Rob Arndt

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VS 5 was an experimental semi-submersible torpedo boat (Versuchs Schnellboot) completed in 1941 and based on a 1938 patent by a Berlin dentist. The intended armament included two 21in torpedo tubes and two 2cm cannon. Its fate after 1941 is unknown.

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I don't believe the Sub-sailboat idea would work well. Here are a couple of points.
Sailboats are built to be as light as possible, with exception of Keel, so that mass to be move by the wind is less. Hull friction is also minimized by reducing wetted area as much as possible. A submarine is the opposite, they have to be heavily built all the way around including the windows and doors to be able to take pressures of even descending a few feet. A submarine also needs more equipment, thus more room needed, and more weight.
So let's take a 26 foot sailboat vs a 26 foot submarine that dives just ten feet to get below surface line in four foot waves. Both are have 8 foot beam and a mast above the waterline of 26 feet.
The sailboat would weight say 6000 lb and have a minimum wetted area. The Submarine would weigh at least three times as much and the wetted area would be six times as much plus the ten feet of submerged mast. Then assuming wind puts same forces on either mast, the forces on the submarine mast would be greater because of leverage and additional mass of sailboat.

I know this is not a perfect analysis but hopefully enough to show some of the forces involved. A swath sailboat would have similar problems compared to just a simple catamaran or monohull.

One last but important point. To operate the sails; How do you have to get out of the cockpit? How do you change sails?

 

Shoe Sub

I think it went condo
[IMG]http://media.weirdworm.com/img/life/6-weird-places-where-people-actually-live/shoe-house.jpg

 

Uber33t,

Look at a Janes book of ships. Look at the tonnage for a sub. Then think about trying to push that with any rationale sized sail.

Then understand that I was on a US military sub at 300' taking 30 degree rolls due to the surface waves in a cyclone.

You need to look at the weight of any sub and start from there. If hydrofoils would work on a sub the military would have them. The idea of running away from a torpedo at 50KTS would make any captain demand them.

This is a really bad idea that has no possible value. Just do the math for anything. Sail area, hydrofoil area, or power required to push the hydrofoils.

No - not doable, ever.

You need to start looking at the Concrete sub threads. If that doesn't cure you nothing will.

 

There seems to be some people that fall for the homemade submarine being the perfect ship. They want to build it like they would a regular boat, in their garage, with used parts, they want to add sails and solar panels to their designs to save even more money. I propose that we name a syndrome to categories these free thinkers after someone who inspired them Wellmer. People with Welmer's syndrome have no fear of drowning or getting crushed. They don't believe in the physics of inward pressure or the necessity of breathing. Surely next they will look for investors for their idea.
An ocean or even lake is a very hostile environment to risk your life in. Please do things carefully and get professional help when working outside your field of expertise. You can get hurt or die in a boat, in a submarine it will happen ten times faster, from the slightest mistake and no one may find you.

 

Supporting upchurch's post, here is a diagram every sub builder should see that thinks they will escape waves just below the surface. Note that the depth you need to go is L/2. Sorry for the large image. It is directly linked as opposed to uploaded to save bandwidth for the forum.



And... from a surfing site, here is an explanation of the wave depth...

" If the waves in a wave train have sufficient energy (normally a period equal to or greater than 15 seconds), they can continue with little loss of size or energy, for thousands of miles or until they reach land and break. That's because at these periods (or wavelength) all the energy is traveling deep under the oceans surface, and there's little that can stop it (except for shallow water). A wave with a 14 second period reaches down into the ocean about 516 feet. A 17 second period wave at 761 ft, 20 second at 1053 ft and 25 secs to a whopping 1646 ft! "

 

Notice Catbuilders illustration. What you might not catch is that at the wave trough, the motion of the water is in the opposite direction. The water moves sideways, but since a wave is not the same thing as a current the water has to move sideways at the crest and back at the trough - it doesn't really go anywhere over time. This is what pushes on the sail or conning tower of a sub, and there is very little to stop it! If you can't get deeper to where the effect is very small, the only thing keeping you upright is you changing the settings of the planes to resist the roll, and that only works if you are moving forward. So much for just swatting to avoid the surface effects. This will be just as much work as working the tiller to avoid getting knocked by large waves, its just harder since you cannot see them coming, you are underwater. Better bring your Dramamine since you will have no horizon to focus on to avoid seasickness.

Thats all I have.

But there was one mistake. No one will spend excess rescue funds since no one will be able to find where you went down. Darwin at its best.

I really hope those with positive opinions are just engaging in speculation for the fun of it. I don't actually hope Darwin will get anyone.

 

I think one or two of us tried to make the point about the depth you needed to dive to escape the wave-affected zone to tugboat on his concrete boat thread. As I recall the guy didn't want to hear it, and still probably believes that it's realistic for a small DIY sub to get beneath bad weather.

Those of us who've been on subs know the motion can be pretty evil when it gets rough, especially if the boat can't go deeper than PD in the area.

 

I think all of these home built ideals would be forced to run at snorkel depth or shallower during storms. They will have no greater speed than the bog standard cruising sailboat so will need to stand and take it offshore. How effective is roll damping? How easy will it be to control trim in waves? Is a snorkel which can be designed to alternate from free to awash within the design capabilities of a backyard engineer?

Or maybe the thinking is to go a tad deeper and play possum with no propulsion till the weather clears?

 

My guess is that roll damping will be inherently very poor. Even if active differential plane roll control was used the low cruise speed would probably only give a limited roll stabilisation capability. The control software to get it to work well would probably be complex, too, and have to be custom tweaked to fit the roll M of I and deal with variations due to fuel and ballast state, wave period etc.

My limited experience was that both roll and pitch were affected by wave action while running at PD in fairly shallow (European Continental Shelf) waters in bad weather, producing a fairly unpleasant corkscrew motion. Roll angles were pronounced and the planesman was having a tough time with depth keeping. A DIY boat would almost certainly be worse, both by being smaller and lighter and by lacking some of the stability augmentation control systems that big boats have.

 

Any Ideals on snorkel requirements Jeremy?

It appears that in operation the submersible would be caught between having to run sufficiently deep to keep out of rollers and yet within the capabilities of the snorkel.

How tough is it to design a snorkel to deal with alternating submerged/free?

 

Outside my field of experience, TBH, I was only involved with weapon trials and had very limited sea time and no sub design experience. I do know that it is hard work to keep a big boat at PD in bad weather, particularly if the boat wants to keep it's surface signature down by keeping the bearing tube beneath the surface. The high inertia of a big submarine must help a lot to damp heave, I'd guess, so I would imagine a small sub would go up and down a lot.

Having said that, the Columbian drug semi-subs seem to work OK (although we don't know how many succumb to bad weather). The pictures I've seen of them show relatively small schnorkels, but they don't seem to run fully submerged, so presumably have greater buoyancy than a sub at maybe 10 to 20 m down.

 

Down Periscope is airing on HBO just now.
Pretty good fare for a Wednesday night.

 

All the sub narratives I've read say even at periscope, or maybe a

little deeper, things totally calmed down.

But I can't remember if they were dealing with big waves(that might have come from far away) or current storm and wind.

These were mostly U-boat stories and I do remember hearing U-boats had a big extra lead keel(besides the batteries) to enable it to dive. That Brit sub that got captured featured a releasable keel, which was release allowing them to float up and survive.

I don't remember hearing about either extra lead or releasable keels on any US subs.

And here is hydro-foil amphibian mini-U-boat. Not sure how "reality based" this design was, physics and numbers wise. 1600hp and 15 tons empty/50 tons loaded and HYDROPLANING??? Even with that big air cushion?

But at least it would have a nice big flat deck for sunbathing if adapted for civilian use....and in land mode would provide large shade/rain awning!!!

I'd imagine the wheels would retract once in the water and in hydro-foil mode.





MANTA HYBRID SUBMARINE/HYDROFOIL

(1945)

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Another project stemming from the co-operation between the Walter facility and Versuchskommando 456 was the Untersee-Gleitflächen-Schnellboot Manta (USG submarine). The idea behind its construction was to bring together all the progressive ideas from the various miniature submarine designs in one new project, particularly the necessity to obviate the drag caused by external torpedoes and the need to launch the vehicles into the water easily and successfully.

The Manta had a catamaran-type hull comprising three torpedo-like cylinders linked by one wing surface. The central cylinder contained a diesel generator and a cabin for the two man crew; the rest of the craft, as well as the other two cylinders was given over principally to fuel (Ingolin) storage. In addition, there were trim tanks and compensating tanks.

The propulsion system was installed within two keels beneath the outer cylinders and consisted of one Schwertwal-I-like unit in each. As well as the diesel-electric propulsion system, a diesel-hydraulic transmission installation was also considered. At the sides were to have been located two large aircraft wheels, to enable the craft to hydroplane on the surface of the water.

The wing area between the two outer cylinders was to be filled with four launching tubes for torpedoes or mines. Navigation equipment was similar to that of the Schwertwal.

As with all the Versuchskommando 456 projects, the Manta designers paid close attention to crew survivability by providing, for example, a marker buoy with an antenna, a self-inflating dinghy and special diving suits. For an acute emergency there was the option of jettisoning the two electric batteries -which acted also as ballast- from beneath the side keels in order to give the craft added buoyancy and assist it to the surface.

The Kleinst-U-Bootwaffe (Miniature Submarine Command) gave its blessing to this project, not least because it fulfilled a determination to achieve the maximum concentration of weapons whilst employing the minimum number of men. However, Manta did not progress beyond the stage of a model, and at the end of the war all the design documents were destroyed.

Data:

Crew: Two
Diving Depth: 50-60 m
Length: 15 m
Beam: 6 m
Maximum hull diameter: 1.5 m
Displacement: 15 tons empty/ 50 tons loaded
Electric Motors: 2x 440 Kw
Diesel engine: 2x 600 hp
Or Walter engine: 2x 800 hp
Maximum surface speed: 50 kts
Maximum submerged speed: 30 kts
Surface range: 200 nm @ 50 kts/600 nm @ 20 kts
Submerged range: 120 nm @ 30 kts/500 nm @10 kts
Armament: 2 standard or 8 homing torpedoes; 8 TMA or 12 TMB mines; or 4 projectiles*

*possibly rockets

~ The Encyclopedia of U-boats

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