Type of Wood for O/B Mount in TY Senior

[MHBsailor]

Last season I had some difficulty getting my new 6HP 4-Stroke Yamaha (65 lbs) to mount in proper alignment. I believe this was due to the boat coming with a 9.9HP 4-Stroke Yamaha (100 to 110 lbs) which had a higher and thicker wood mount. I measured the dimensions on a sister TY Senior and they were 5.0-in high and 1.5-in width and was wondering what kind of wood that I should use, as it needs to withstand the thrust and torque from the outboard and I presume be of marine grade (in my experience they are usually varnished). Thanks! JD

[John Stone]

I don’t have a Ty and from the picture I can’t tell exactly what is depicted. But any hardwood will work. More rot resistant will last longer if it’s completely exposed 24/7. I would not varnish something I plan to hang an outboard on. Will never last. Most hardwoods will survive fine exposed to the elements. You can oil it with teak oil several times over a few days to get some penetration into the wood.

Ipe is in the iron wood family and very rot resistant. Angelique is good. Iroko is tough and rot resistant as is Purple Hear (though you might not like the color. White oak would works fine. Mahogany is a little soft for this application I think.

A picture with more perspective would help me understand better what it is you are trying to do.

The bottom line is lots of hardwoods will work. There is no secret wood. I didn’t mention teak as it’s just so expensive and ipe is just as durable. There are other exotic woods coming into use as teak gets harder to source.

Try one and see how you like it. Make sure the fasteners and supporting hardware are in good shape.

[MHBsailor]

Thanks as always for your reply John I've posted another photo below. The current horizontal beam the old 9.9 HP 4-Stroke O/B (pictured) rested on is too tall and too thick for the smaller 6 HP 4-Stroke O/B. I initially tried cutting a notch in the top of the beam to reduce the beam height to 5.0-in as on a sister ship with a 6HP 4-Stroke O/B, but it is still too thick, which causes the 6 HP O/B to sit so far forward that the vertical shaft housing rubs up against the front of the opening below the hull and interferes with being able to swing it left and right to aid tight turns). The 9.9 fits in proper alignment fore/aft with the taller, thicker beam. JD

[tjr818]

For a 5" x 1-1/2" board you could us a fir or treated fir 2x6 which should measure 5-1/4" x 1-1/2". Fir is very weather resistant and not expensive, a good coat of paint would dress it up very nicely. Fir is also quite strong.

[Jim Walsh]

That looks like a piece of Douglas fir. It would be excellent for that application if you can find someone to run it through a thickness planer and trim to the height you desire. That’s what I use for my fender boards.....lasts forever.

[John Stone]

Much better picture. Concur. Looks like fir but I don’t think it’s Doug fir. Looks like it’s sitting on top of some other kind of wood. Perhaps teak but I can’t tell from the photo. Anyway I agree with Tim and Jim. Another option is a deck board for home decking is 1” thick. So that might be an inexpensive solution. There is not much load on it. It’s so short that a 1”-1.5” board is plenty strong. I’d probably be inclined to stay with 1.5” thick board though. And add some SS washers under those hex head bolts.

Because the aft end of the motor mount determines where the shaft is positioned relative to the boat, the thickness of the board on the forward face of the Bracket has no bearing on the position of the engine. It would be different if the board was bolted on the aft side of the bracket. Make sense?

[MHBsailor]

Thanks Jim and John! As for the mounting position of the outboard, it was empirically determined based on how the new 6 HP O/B fits currently. Because the Yamaha is such a tight fit due to the rather large housing, I may need to get a 6HP 4-Stroke Tohatsu SailPro, as their housing is considerably smaller as it can be ordered without an internal tank that most 6-HP 4-Strokes seem to come with these days. The SailPro also has the advantages of an extra long shaft and a standard alternator.

JD