V105-V108 WWI German Torpedo Boat

Will you be making batches of the torpedoes for sale?

Pretty please?

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Tug don’t be torpedoing your liner I’m pretty sure your wife will make you go down with the ship []

 

I'm thinking it's more feasible to pick up a couple of flat-rate priority mail envelopes, open and flatten each, laminate a layer of 0.5oz fiberglass mat to each side using West Systems Epoxy and cutting out the ribs on those. I used up the last of my balsa stockpile attempting to get one good set of ribs made out of balsa since I don't have any plywood left after taking on the project of repairing a Princess Anne dressing table. Even better yet, I may just bite the bullet and make a plug/mold; it's not as if a plug that fits on an 11x17 sheet is going to leave me pressed for space overnight.[]

On another note, the distance between rib 2 and 3 is 1.375" between the surfaces (not on-center) in case anybody's still looking for the rib position.

 

I have to determine where my camera disappeared to but I did take the center of a bottle cap and make something of a prop out of it (the corresponding hull is, of course, proving more stubborn).

 

I have been using aircraft ply. Will try balsa as it is easier to cut. Went rugged for the first one.

 

Webwookie, does Unigraphics allow you to substitute materials easily to find out how different construction materials would affect the weight and center of buoyancy?? What I'm wondering is if things get too heavy or unstable if the ribs and keel were made from 1/16" thick stainless steel. The deck would still be wood.

Another question, I think some clubs allow increasing the volume of hulls if the ship was under a certain displacement, to make construction more feasible. Is this designed per plans, or with addt'l displacement?

 

3/8" depth has already been added to improve displacement; According to the numbers, Stainless is too dense to use for the ribs and keel (unless enough power is available to run everything using the weight of only two AA size NiMH cells, perhaps with a LiPo pack instead) although grade 3 titanium sheet would work along with fiberglass, kevlar, or carbon fiber sheet. Any of these materials would probably be best if laser-cut though. I may look into building a plug to mold some fiberglass hulls of a semi-single use sort of grade/durability in the future though; it is small and a mold certainly wouldn't take up too much space to store.

 

I figured that the weight would be an issue. Laser cutting some of the other materials might be possible, but would require careful research. We recently found that a material we were planning on cutting releases toxic fumes when burnt, or as in the case of a laser, vaporized. Our system does not have sufficent ventilation to safely remove the fumes. I'm not saying any of these materials release this type of fume, only that the MSDS's and OSHA site would have to be carefully checked before cutting to insure safety.

Titanium seems like it may be a possibility. But like you said, fiberglass would be easiest.

 

From personal experience, I can say that there are plenty of types of composite sheet/board that will release toxic fumes that need to be processed by a ventilation system using activated carbon and there are quite a few out there that don't require any special provisions.

Tugboat, how's your V106 going?

 

Webwookie, If a guy were to make a plug and build one of these out of fiberglass, do you have any idea what type of mat would meet weight requirements, and the max number of layers that could be used??

 

I'm not sure exactly but if you vacuum bag the layup into the mold, I believe it might be possible to go with as much as two layers of 3oz plus one layer of 0.5oz. Otherwise, I wouldn't go over three layers of 0.5oz or so. With a twill weave fabric, a single layer of 5oz fabric might do it if it's bagged. (This is, of course, just my quasi-educated guess based upon my own experiences working with composites. Your results may vary.)
The only way to be sure is to give it a try. While I don't feel bad about the weight estimates from the computer, I definitely wouldn't assume it to be dead-on.

 

Revised plans have been added to the first post of the topic. I'm looking into revising the deck and keel so that each can be divided into a couple pieces and allow the templates to fit onto 8.5"x11" sheets. (However, it doesn't help the issue that the design is still very fragile due to the inherent need to be extremely light-weight.)

 

That is a good article Tug, but it is now approaching 10 years old, an update would be dandy.

Wookie, the new revision is fantastic.

 

If you want a really lightweight hull do this (tug you'll love the
recycling aspect) use your wooden ribs and fill the spaces between
them with pink or blue insulation foam, trim this down to shape
roughly with a knife then final sand this with progressively finer
sand paper until you are down to the level of the ribs using a 6" or
longer "t" section of aluminum as a sanding block. Once it is all
nice, paint on thinned white glue to seal the foam (just in case) Now
carefully cover your "plug" with clear sandwich cling wrap, take
your time and pull out all the wrinkles (or as many as you can this
will be your release surface)now cover the whole thing in worn
pantyhose (not new as it will not have been stretched out yet)cover
this pantyhose with thin or medium CA if making small parts or epoxy
thinned down with alcohol and while still wet add a second layer of
pantyhose and ensure it is also whetted out. When dry cut off the
overhanging/unwanted material and pull out your plug carefully so it
can be re-used. now you have a EXTREMELY light hull that is you want
you can add a layer of fiberglass mat inside or just another coat of
resin/epoxy after making sure you cleaned the molded part and sanded
lightly. on a small boat this will work great, (Also works well on
airplane cowls)

the neet thing is the re-enforcing if needed is on the inside so can
be made into your water channel etc and not add much weight.

 

Just thought I'd let everybody know that I finally found some free time tonight (roughly the next two hours) so I'm going to be trying to revise the design to split the keel (and thus allow it to fit onto 8.5x11 sheets) and add some more details to the drawings for superstructure and the like.
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I've also gone ahead and sent out the data for a quote to see what sort of price that an SLA plug of the hull would cost.

 

If you really want to make a hull out of FG use no more than 2 layers of 1.5oz glass mat and GP Polyester resin (unwaxed) this will give you the strong and light hull you need and give you more room in the hull as opposed to the rib method. I will try making a plug and mold later this winter.