Why Oak hull frames (ribs) on my boat while carvel planks are mahogany.?

by Claude
(Canada)

I own a 1966 Pacemaker 34.

I have the original purchaser's owner's manual.

They say the Hull frames (ribs) on my boat are made of oak while carvel planks are mahogany.

My bilge srtingers are made of Mahogany.

Why are the ribs of the hull made of OAK?

most of them need replacement and I wonder if I should substitute them for another type of wood.

I'm at the start of this project and want to make the right call.

Any help will be greatly appreciated.

Claude

Comments for Why Oak hull frames (ribs) on my boat while carvel planks are mahogany.?

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Pacemaker Sedan's Frames...
by: Mitchell

I rebuilt a 1967 Pacemaker Sedan Bridge 37' from the keel up and did the same type of work on it as you are looking to do on yours. Pacemakers have a unique style of frame that works well considering their relatively narrow width and thickness.

Each steamed white oak frame butts against the side of the keelson. The frames run at right angles to the keelson, across the bottom and side planks and connect at their opposite end at the gunwale. Each frame secures the skin of the boat and defines its shape.

A second piece of white oak is glued and screwed to the top of both halfs of each frame, and the run from chine to chine. As these pieces are securely attached to each frame half, and have a continuous run across the keelson at each station, they tie the two frame pieces together, as well as the two sides of the boat.

In the stock configuration, a floor timber runs from stringer to stringer, and is securely attached to the top of every fourth frame. I doubled these up and ended up having a floor timber every second frame between the stringers. The result was a far stronger feeling boat that was noticeably more rigid. It was also quieter, groaning far less in heavy seas that it did.

I also added two pieces of white oak, 14' long by 12" wide by 2" thick, that were shaped to conform to the shape of the hull at the chines, and through bolted them to the hull frames for a great pair of Bilge Keels. About 90% of the boat's rock and roll was removed, and they made the boat a dream to run in any sea. The boat's performance wasn't effected, but getting the boat to slip sideways became impossible.

My email is billy.mitchell.275@gmail.com if you'd like to contact me for more info on this. I do have a photo or two of the bilge when I finished it.

Cheers,

Mitchell
Similar Question
by: Dan

Claude,

I have a 1967 Pacemaker 31 made from White Oak ribs with Philippine Mahogany and asked a similar question a few weeks ago.

If you replace or install sister ribs, be sure to use WHITE OAK, not Red Oak. Apparently, the Red Oak is too porous and will not last.

I would be interested in following the progress of your restoration.

Dan
Oak Frames?
by: Mike

Oak has been used traditionally because of it’s strength and availability.

But they don’t have to be oak, you could use larch, (hackmatack or tamarack) ipi. Or Rock elm.

I laminated replacement frames for my boat using rock elm.

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