RC Vietnam River Patrol Boat

[Gregor77]

Here I go again.

My friend Frank B, not to be mistaken from Frank V, traded me a bunch of vintage Gijoe 1/6 scale Vietnam figures (battle base, anti aircraft gun and some figures). I also have in my collection some of the tunnel rats and the traditional dragon models Vietnam figures. That got me thinking of doing an RC patrol boat over the winter.  Does anyone know if that is doable in foam and plywood mix?  I get lots of plywood from my current job as we remove it for effected homes.  Remember it needs to be light enough to transport as it might be 4-6 feet long.  I know ballast is an issue with boats.  Electronics should be easy.

Is there a good resource for boat templates?   

What can I seal the wood with that make it water proof and is there a wood that will flex around the hull?  I was thinking very thin plywood then covering with 3/4 cloth and priming?

Any input would be great.

Xoxo

[GuyOReilly]

@Gregor77 , I am following this build because I like boats too.   

[Gregor77]

@Gregor77 , I am following this build because I like boats too.   

[GuyOReilly]

I do not know if you are aware of this information  on RC Unic=verse...
https://www.rcuniverse.com/forum/speed-rc-gas-boats-236/5647069-vietnam-era-pbr-patrol-boat-riverine-plans.html

Guy

I also found this:
https://modelshipworld.com/topic/16248-pbr-mark-1-river-patrol-boat-by-thistle17-model-shipwright-guild-wny-scale-16/page/2/

[bfeist]

One should be painted up as a young Laurence Fishburne.

[sihinch]

I bought a little brushed RC boat recently, to do to the cottage with.  It was super fun!  I enjoyed it way more than I thought, and much more than an RC car......

[Mike_Kilo]

I have no actually experience with model boats, but here are my thoughts based on the woodworking and RC experience I have.

I see no reason why you couldn't do a ply skin on a foam core.  You will likely end up with an unsinkable boat.  One worry is it may end up too buoyant, and require excess ballast, so maybe don't use too much foam.

In theory you could use almost any wood as long as you seal it fully.  Thin plywood is a good choice for bending around forms, as it is strong in multiple directions, thanks to the alternating grain directions of the individual plys.  Just be careful as the glue used to laminate most plywood is probably not meant for contact with water.  This won't be an issue if seal it fully, just something to be aware of.  I believe you can buy marine grade plywood, with waterproof glues, but it is costly and probably not easily available in the thin sizes you would want for a build this size. Just seal both sides and all the exposed edges of whatever you use.

You can shape plywood, and other woods by wetting/heating/steaming it to soften it.  There are loads of methods.  See Franks recent DR.I cowl build using bent balsa. Also google wood bending or steam bending.
I think balsa or another soft wood would not be very durable for a boat hull. I would go thin plywood or hardwood. I think for 1.5 meter (1/6 scale) hull, the added weight of a denser wood will not add too much to the overall weight.

As for sealing the wood, you could look to full size wood boats and see what products are used to seal them.  There are lots of products meant for this task, water based finishes, oil based varnishes, urethanes, epoxies, paints etc. Just look for a product designed specifically for boat exteriors, or something rated for direct contact with water.  I would guess any hardware store "exterior" rated wood finish or paint would serve the purpose, again, as long as it full seals the hull, and dries hard.
Watch the end grains (edges) as they will absorb more, and require more sealant.

If you wanted a super strong full, you could laminate over the plywood with fiberglass cloth and resin, making a wood/fiberglass composite hull.  You could also shape a foam hull, and fiberglass that, leaving the wood out of the equation, making for and even lighter hull.  Lastly you could go all out and lay up a 100% fibreglass hull over a removable form, just like a real PBR, but this is pretty advanced and requires some special skills and tools.

I think the main take away here is to look to full size wood boat building techniques, as they are very old and well established, and scale them down.

Electronics are easy, as there are lots of motors and ESCs designed for boats.  Most of them are water cooled, requiring a water inlet in the hull and some plumbing inside the boat, but its not too complicated. Servos and RX's can be bought waterproof, but not totally necessary if they are well covered.

Running gear will be an interesting thing to sort out.  RC jet-drives can be bought, and may not be much more complicated to install than traditional running gear (prop and rudder.) Likely costlier, but I think a a dual jet drive, 1/6 scale PBR would be pretty sweet.

Very interested to see how this pans out!

[Frank v B]

When I read posts like:

Greg's: "That got me thinking of doing an RC patrol boat over the winter."
Guy's: "I am following this build because I like boats too.   " and the boat on the shelf in the background of a Minimoa photo.
Simon's: "I bought a little brushed RC boat recently, to do to the cottage with.  It was super fun!"

I have to come clean with my stash:
Photo 1- my 48" Tug. Given to me by an estate, 54 pound, 35 pounds of lead ballast and the little Graupner Pollux tug in front for my grandchildren..when I am finished sailing it.
Photo 2: the twin motors geared into one bronze 3" 3 bladed prop. Runs on 6 volt sealed batteries.  My first try with a 2 cell lipo (7.4 v) made it plane.  6 volt is perfect.
Photo 3: my 3 RC sailboats.  The red one in front (fibreglass) is one I built when I was 14 years old.  It still sails great.  The big black one was given to me by our club member John Werner.  I had to figure out the keel and rudder and cobble together a mast out of a carbon rod.
Photo 4: my 2 RC submarines.  The large white one is the Dumas USS Bluefish.  The black one is a wooden one built out of door skins from plans published in the British Model Boats magazine.  It has been down 6'. Both are dynamic divers (no ballast tanks, they use forward dive vanes to force them down).  Note: submarines use 72 meg FM radios because it gives the best control under water vs 2.4 gig and AM.  The antenna is coiled up in the conning tower.
Photo 5: my Dumas PT 109 33" hull as given to me.  Ready for wave 2 Covid shut-down.


Frank