What keels are made of

[pilot_ed]

I have seen small sailing craft, have the keel made out of laminated ply glued together to make the thickness need but on all larger sailing craft it is formed out of a large tree. why is this so, is it that the keel is easier to make from several pieces of lumber? A curious mind would like to know if anyone has any input on this!

[Bob Cleek]

By laminted ply, I assume you don't mean laminated plywood! The reason many keels are built up today from laminated plank stock is because it is easier to come by than larger balks of timber. The larger log is more costly to handle commercially and generally more wasteful of wood in the shaping. It is also more difficult to obtain properly clear and check free solid timber in many places. However, there is no reason why solid keel material shouldn't be used when available. It is a lot easier to work than laminated, as it doesn't have grain running every which way and hard glue lines running through it. There is also the advantage that a solid keel is not ever going to delaminate, which laminated keels occasionally do, with predictably terminal results. Your guess was right.

[pilot_ed]

Thanks for the info Bob. The reason for asking the question is that I was thinking of building a cold molded hull and then fiber glass the whole thing. this will seal the whole boat and want to know the ins and outs if I was to try a laminated keel intead of a solid tree keel. Thanks again for the input.

[ 08-21-2002, 03:05 PM: Message edited by: pilot_ed ]

[Seth Wood]

Yah, Dave F. I was wondering the same thing about the forum topic. Mea culpa for continuing it over there! Switching to Building/Repair...

Re: lamination thickness, I think Gougeon Brothers recommend no more than 3/4". That's a lot of layers for a big keel, but I'd be worried about severe swelling in anything much thicker.

Larry Pardey's book, "Traditional Boatbuilding Vol 1: The Hull," introduced to me by others on this forum, has a few good points early on about Larry's lamination of Seraffyn's (curved) keel and stem. He went for solid on his next boat.

Still, if you're committed to cold-molded, I think a laminated keel timber is the way to go.

[Dave Fleming]

Seth, the O&O CABAL out of the magnificence of its heart. :D
Forgives your transgression......

[pilot_ed]

Thanks seth. Iwas thinking of using a 1/2 inch for the laminate. So if 3/4 inch is to think then i should be good to go with the 1/2 and sorry again to all for posting in both forums but was not sure which catagory the question fell under so just posted in both. sorry sorry again and thanks for all the info everyone has provided!!!!!

[thechemist]

Originally posted by pilot_ed:
Thanks for the info Bob. The reason for asking the question is that I was thinking of building a cold molded hull and then fiber glass the whole thing. this will seal the whole boat and want to know the ins and outs if I was to try a laminated keel intead of a solid tree keel. Thanks again for the input.You never will really seal the whole thing. Water *WILL* diffuse through the fiberglass/anyone's-brand-epoxy and the wood *WILL* swell and the glass/resin layup, if not flexible enough, *WILL* crack and another one bites the dust.

Ventilation is the key. Ventilation is what allows the small amount of water that *does* make it through to evaporate off the inner surface of the top of the keel, inside the hull.

With no ventilation, you buy into the epoxy-encapsulation myth. Use the search thingy in the upper right. Put the word "encapsulation" into it, searching in the entire post [not merely titles], in Building/Repair, and see what you get.

Ideally, one would build a laminate-covered solid wood keel with a few ventilation passages from above, right through the middle, down to near the bottom, across fore-to-aft and back up, and have perhaps a bilge-mounted air-mover maintaining a continuous flow of air through the ventilating passages. One would not need much.......likely even the prevailing winds could be captured in a funnel-mouthed ventilator topsides and directed to flow through .....but that sort of thing seems not to be done in routine construction. Dunno why...it seems logical.

[Bob Cleek]

Well, then, on the other hand, you could abandon the fantasy of a cold molded hull and just build her traditional plank on frame. One whole heck of a lot less work. If done properly, just as good and a lot easier to work on down the line. Oh, and then too, you won't develop an allergy to epoxy and be itching yourself to death, either. Besides, the smell of fresh shavings coming off a plane beats a nosefull of epoxy and acetone fumes hands down. The traditionally planked boat will cost a lot less to build and also be worth a lot more when finished than the cold molded job, boat for boat. There's a place for epoxy and cold molding (generally rather small craft), but think about it. Those books about how easy any fool can slap together a cold molded hull are written by the guys that sell the stuff.

[Dave Fleming]

Cleekster, not argueing with ye at all but, have you seen some of the big vessels being built of goo these days? IIRC, some group in GB built a 100+ footer using the stuff and there have been a number of that size done in this country too.
I still can't get this old haid around the methods of how to do hull repair on such things!

Yeah Yeah, I understand the mono....thingy but????

[pilot_ed]

Thanks Chemist! I had planned on putting lots of ventalation in the bilge area. I plan on putting ventalation fans forward and aft to move air through out the whole boat and the bilge area.

Bob Cleak I had decided on the cold molded hull because I like the idea of the strenght of the hull when laminating each layer 90 degrees to the last. I strongly feel that four layers of cold molded hull will resist a much greater impact than a single piece of wood the same thickness. But this is just my belief. I also know that it will take more time and be more messy, but i am only doing the hull the rest of the boat will be all finished wood except for the mast.

[ 08-22-2002, 12:38 AM: Message edited by: pilot_ed ]