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

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Blog entry by shipwright posted 1282 days ago 2247 reads 0 times favorited 10 comments Add to Favorites Watch
« Part 14: Cold Molded Planking Part 15 of Shipyard Memories series Part 16: Boring Bars and Custom Castings »

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 off-setts 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

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/



10 comments so far

View Bearpie's profile

Bearpie

2586 posts in 1644 days


#1 posted 1282 days ago

I see there are more aspects to boat building than I had assumed! This would be out my league.

Erwin, Jacksonville, FL

-- Erwin, Jacksonville, FL

View Dave's profile

Dave

11149 posts in 1466 days


#2 posted 1282 days ago

truly amazing, Your shop is a little small for me I dont think I could find a place to set my toolbox. lol ;)

-- Superdav "No matter where you go - there you are." http://chiselandforge.com

View Bluepine38's profile

Bluepine38

2876 posts in 1712 days


#3 posted 1282 days ago

I have always loved being on a sailboat when the wind and the waves were up and hanging on the upwind
side to coax just a little more speed without too much lean, finding out how much weight was in the keel
makes my efforts seem a little puny now. Thank you once again for sharing your skills and knowledge to help
us better understand boats and realize how much skill goes into building a good ship.

-- As ever, Gus-the 75 yr young apprentice carpenter

View Div's profile

Div

1653 posts in 1567 days


#4 posted 1282 days ago

I’m not really looking at the photos, too scared of that itch….!

-- Div @ the bottom end of Africa. "A woodworker's sharpest tool should be his mind."

View Pawky's profile

Pawky

278 posts in 1430 days


#5 posted 1282 days ago

I’m really enjoying reading this series to see what it is you do. Thank you for continuing to share

View Napaman's profile

Napaman

5332 posts in 2704 days


#6 posted 1281 days ago

great stuff…with all that we know now…do you think you would want…or be required by law to wear more respiratory protection?

-- Matt--Proud LJ since 2007

View shipwright's profile

shipwright

4900 posts in 1424 days


#7 posted 1281 days ago

Matt, we knew it all then. It was only an hour or two, I was wearing activated charcoal filters and the thing had to be done. Since then I’ve always used lead that someone else had already made into ingots. You live and learn.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

View SPalm's profile

SPalm

4784 posts in 2508 days


#8 posted 1279 days ago

I have been away for a while and come back to read these wonderful blogs. Truly fascinating, I just love it.

BTW, we were just spending time in St. Martin, and I thought about you a lot. The boats there are incredible.

Keep it up,
Steve

-- -- I'm no rocket surgeon

View tdv's profile

tdv

1114 posts in 1697 days


#9 posted 1278 days ago

Nice one Paul I love the way craftsmen have developed & discovered techniques & skills over the centuries & these boatbuilding blogs are a great example I hope they are never lost. Todays technological society seem to discard old knowledge as not being relevant & yet it still underpins even the latest computer
Thanks for sharing it Paul
Trevor

-- God created wood that we may create. Trevor East Yorkshire UK

View swirt's profile

swirt

1937 posts in 1598 days


#10 posted 1278 days ago

This series is an amazing read. Thank you.

-- Galootish log blog, http://www.timberframe-tools.com

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