Pacemaker Boat Owners Association

I don't know what the origanal ones are made out of but I would look at useing oak.

Use white oak, it's more resistant to rot than red oak. Clear grain too, no knots. Good luck.

I just replaced the engine stringers on my 1972 32'. I believe the original stringers are fir plywood glassed over with a heavy woven roven (IMHO it was not marine ply as there were visual knot holes). I repaired/replaced them with oakum marine plywood glassed over with a 20 ounce biaxial cloth. Just incase you are talking about the engine beds IMHO my pace had southern yellow pine.

white oak

Are we talking about fiberglass engine stringers, wood engine stringers or engine beds? I agree that engine beds should be Oak. If we are talking about repairing fiberglass engine stringers the closest material to original (at least on my 71 32’) was marine plywood.

His boat looks wood to me,
Sorry white oak was used for ribs, slow growth spruce or pine is what they used for the stringers I think white oak would be to much better but then it is much heavier. Pine isnot the best for rot bit but they will be fine if kept dry.

Was it just the weight issue that had them useing pine or spruce?

I don't really know but I would think that would the reason or maybe it was the flex. i would think that pine would flex more but could think what the beams would weight if they were oak

Spruce is 23lb per cu ft
White Oak is 47lb per cu ft

The original engine beds in my 25-footer were made from Douglas Fir, which is a good, load-bearing species.. I eventually needed to replace them due to rot. I could not find large enough pieces of Fir locally (the Tampa Bay area), but I was able to find Cypress without an issue. I chose to use cypress due to its rot resistance. The beds have been in use now for about six years and seem to be holding up well.

Kind regards,

JoeBobb

Looks like you like boats in more ways then one Joebobb (:

It's a love-hate thing...

I am with you 110%

There are two considerations here: (1) rot due to water, and (2) rot due to petroleum products. Water - especially salt water - will eat away at the "softer" parts of the wood (by leaching away the wood's natural binding resins, thereby allowing air to decompose the soft fibers). Petroleum products (gas, diesel, oil) simply dissolve these resins throughout the wood, performing the same job.

The engine stringers get subjected to both types of contamination, as the years pile on.

Some woods are more resistant to one infiltration than others; but no wood is impervious to both. Even fiberglass will fail in the presence of excessive petroleum contamination.

As a carpenter and a structural engineer, I'd say that your best bet is old-growth fir, which has extremely good petroleum resistance, moderately good water resistance, and a high tensile strength (load capacity and flex resistance). I'll add more to make this choice more attractive later.

There are few resources for "new" old-growth fir, but there is an abundant supply of it...if you're willing to spend searching time.

Most older houses (built between 1900 and 1920) were built with old-growth fir - it was plentiful then - and many of these are being demolished as we speak. Even one house that appears to be collapsing upon itself still has hundreds of feet in perfectly useable old growth fir. And these studs & joists will be far thicker, deeper, and longer than you need for your job. I'd suggest you check with a company who will be demolishing a house near to you, and see if you can't get a piece from the demolished building.

Once obtained, cut & shaped to the desire size, look into having your stringers impregnated with PTFE (a product developed by DuPont and sold as "Teflon"). The PTFE addition will not only give these old pieces added strength, but will also add an easy 50 years until you need to address the issue again.

I did an old 1951 wood boat (I forgot the make, if there was one) back in 1981, but I can tell you that the "Amilee" is still afloat today...and those stringers are still there.

my father worked for the leeks in the pacemaker factory. any boat over 30ft got fir stringers.my 36 still has the originals. back a engine mount bolt out and smell the wood.