Shipyard Memories #15: Rolling Hulls Over and Pouring Lead Keels

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This is part 15 in a 22 part series: Shipyard Memories



Once the hull is planked, it is skinned with 6 oz. fiberglass cloth set in epoxy and faired using several tinted coats of a high build epoxy primer and quite a lot of sandpaper. The last coat is grey and only sanded enough to knock off the dust nibs.

Here the skin is on but the spray-on fairing primer has not yet been applied. The white patches are epoxy filler applied between the wood and the 'glass with a batten screed to fill the more pronounced low spots.

 

In this photo the last primer is on and we're ready to roll her over. The rolling jigs are in place, bolted through the keelson and the sheer strakes in places that won't show later.

 

The first job is to lift on one side until the hull rests on the first flat side of the rolling jig. This is a fairly tense time as there a lot of balls in the air so to speak. Stops to check balance and move shim blocking are frequent.

 

Once the hull rests on the first flat, the forklift moves to the other side and lowers it down onto the second flat. Then the scary part is over and it's just a matter of tipping her upright. This photo shows her about half way down to the second flat , an interesting view and the first time we get to see the inside from any distance.

 

Once upright, she's set up in a temporary cradle to await the keel.

 

Olfara had a foil shaped keel so a plug of the same shape (but 1/8" per foot larger to account for shrinkage) was built first according to offsets provided by the designer. This is a plug of the lead only. The area above the diagonal surface will be filled by the wooden part of the keel. As you can see the lead is concentrated in the forward part of this keel.
 

Next a strongly reinforced plywood box is built . The plug is placed in it and concrete is poured around the plug which is then removed leaving a mold space for the lead. We placed 3/4" copper pipes in the mold, wired in place exactly where the keel bolts would go. This is way easier than trying to drill two feet of lead with extreme accuracy.

 

In the last segment I mentioned that we'd get to the issue of the lead cable sheathings later. Well this is later. Apparently these cables were wrapped up in lead and lubricated / protected / insulated / whatever with oily PCB kind of nasty stuff. That's what that smoke I'm standing in is made of. I'm skimming the floating slag off the top of the molten lead here. The melting pot is an old hydraulic oil tank salvaged from a commercial fish boat reno welded to a 1/2" steel plate and surrounded by fire bricks for insulation. There is a valve on the front at the bottom and heat is supplied by two tiger torches running on propane.

 

This is a great photo, to me anyway. It shows pure liquid lead flowing freely into the mold. This is really a fun moment (PCB's aside). If you add the lead at the correct rate, pour at the correct rate and have the right amount of heat you can, and we did, pour 6000 pounds of lead in a single uninterrupted stream

 

Here's the new keel being lifted out of the mold. No release problems with lead as it shrinks when it cools. Bloody considerate of it don't you think?

 

Enough for now. I'm being called away.

Comments and questions welcome.

Later

Paul

The early bird gets the worm but its the second mouse that gets the cheese.

very interesting paul.thank you for taking the time to share this part of your life.

working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

I’m guessing that for that much lead, you can’t just get old wheel-weights from the corner garage. But cable sheath didn’t sound particularly great to me, either. What’s the source for big hunks of lead nowadays?

May you have the day you deserve!

You can buy ingots of rough cast lead at metal dealers and even some scrap yards. At the time the sheathings were all I could find. The one nice thing was that they melted very quickly.

The early bird gets the worm but its the second mouse that gets the cheese.

Interesting about the copper pipe being used to secure the drift bolts over drilling.

Main Street to the Mountains