Anybody into model boats?

timtune

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I'm building a plank on bulkhead pond yacht from an old billings kit that's missing parts and instructions.
I've built a mold to cast the lead keel but I'm not sure how to attach the keel or how to tell what weight it should be other than a lot of trial and error.
 
@crankcall might have spent some time with those before. My guess is there will be a geek webpage with a calculator/spreadsheet that helps you get keel weight based on sail plan, design wind and keel depth.
 
There are lots of model boat site but most I found catered to museum piece type builds
 
There are lots of model boat site but most I found catered to museum piece type builds
Can you find pictures of your kit? I was picturing a lead bullet on the bottom of the keel but at least some billings kits look like they just just a solid lead keel and you could probably get close by measuring off a picture.

I suspect you have something like this:

billings-1960-70s-mahogany-plank_360_8739b8758fab001fc8b0d5fbaebac41b.jpg


The ones I have seen before were more like this:
jy8811_a.jpg


Is there a major downside to too much keel weight or righting moment on your boat? It will slow it down a bit but you aren't racing. Just don't go crazy and sink it.
 
This is not mine but similar in that the lead keel is an extension of the the wood keel. Mine is a Billings Pirat which is difficult to find since google is so smart it insists on looking for pirate
1619044603033.png
 
This is not mine but similar in that the lead keel is an extension of the the wood keel. Mine is a Billings Pirat which is difficult to find since google is so smart it insists on looking for pirate
View attachment 48253
Thanks. It looks like you could scale ballast from this drawing.

1590069239_5728_FT36269_hpim0653.jpg



EDIT:
Nevermind. That came from a thread you started somewhere else.

It appears DMI pirat has more useful hits than Billings

dmi-billing-boats-pirat-fitting-set_1_e4981cf0cf670ae18801bb0e27ab8bce.jpg


As you have the wooden keel it attaches you, you already have the width and length, all you are missing is the depth and some shaping. It looks like solid lead (except for the two screw holes) so that sets your weight.
 
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Nice find.

Exactly. That's my post. I am trying to scale from the drawing but I think there is much room for error.
 
make a jig to hold two bolts square to the keel and pour the lead keel so the bolts stick out the top, drill two holes up into the wood and epoxy the bolts up into the wood structure. you'll probably have to scale it from the picture , there is a design ratio but it's for actual yachts and assumes you'll have furniture and stuff in the boat. Pour on the heavier side and leave the fastening bolts up about the midway point so if you want to after a test sail, saw off a portion, or conversely glue on another lead bit and fair it in with thickened epoxy.

some people will drill through the lead 'shoe' and screw the shoe onto the wooden keel portion , that way you can make more than one shoe and swap them out to find the right one. Once you find the right one you can make it permanent .

To fasten a keel onto a model boat with a strut keel as shown in the upper picture use threaded rod from the bulb up through the strut and put a rubber washer and nut in the bottom of the hull.

*shortcut to know if your pretty close , the boat should float to its waterline. once you make the hull and are ready to make a keel , put the boat in a pool and using a variety of weights (wrenches, or sockets) pile them on the center of the deck till the boat is floating to her lines. Remember you'll add a bit of wieght ( but not much) adding the mast and rigging. Weigh all the crap you sat on the deck and that's what the keel needs to weigh.
 
Thanks CC The plans show the other way round. Through drilling the lead keel portion and screwing and then screwing into the wood portion. I liked that option because it allows removal of the lead for trimming. Does that sound reasonable?

You've also answered my other question in that there is no way to really determine the correct lead weight w/o getting model wet (kind of hoped I get it "all" together and then finally paint/finish)

The kit provides cloth for the sails but it will need trimming and seams.
 
Thanks CC The plans show the other way round. Through drilling the lead keel portion and screwing and then screwing into the wood portion. I liked that option because it allows removal of the lead for trimming. Does that sound reasonable?

You've also answered my other question in that there is no way to really determine the correct lead weight w/o getting model wet (kind of hoped I get it "all" together and then finally paint/finish)

The kit provides cloth for the sails but it will need trimming and seams.

I watched a guy slowly build a 35 foot motor sailer, West System. When it was ready for the keel it was external and somehow to be bolted in place.

The keel showed up, cast by a foundry somewhere and it was a huge long beast of a thing but it had been made too heavy. The foundry sent a guy with a chain saw to cut a couple of big notches out of the top of the casting. It lightened the casting leaving the weight as low as possible giving the boat the maximum righting action.
 
@timtune, you probably already know but wear a respirator when you melt and cast the lead keel, the fumes from molten lead are not good for you.
zigzag stich on the sails if your machine allows it, Try and hold a bit of camber into the sails when you sew them, if the panels are precut they should have a bit of a curve build in. A lot of kits have 'flat' sails , the boat will sail a bit nicer with some shape built into the sail, but its an older kit and just a canvas type material , it will stretch a bit and be fine.
 
Camber is that the curve on the long side?
 
Thanks CC hadn't considered the respirator
 
The long side would be the luff curve , you could skip that one on a model boat , its a pretty small effect with that scale. The one I would try and control if you can is the shorter one , like @GreyGhost mentioned the airfoil wing shape, think airplane wing standing up.

I'm in the start stage for a marble head 50 RC boat , 70" mast. I built and sold one , then my friends all got them and got out of RC lasers , now I need another one. F me LOL .
 
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