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Fixing up Andaluz for this year's expeditions. Top of the daggerboard is chewed up. Hoping I can just shmear some marinetex or other material. Not sure of the cause, bouncing up and down while motoring or trailering?

Should work just fine. I've sustained some damage to the top of mine from the board bouncing against the mast foot when trailering mast-up. It's cosmetic on mine and I'm not going to bother to fix it beyond maybe some 4200 on it.

I have made a mold of my 26D DB and am going to produce a few of them for myself. I'm not sure if it is the same as the 26M.
It's not too hard to make a mold so you can make your own.

If you put a knot on the top of dagger board line as close to board as possibleit will help in reducing future damages. It acts as a spacer/bumper so that the board does not hit mast mount or pulley directly.....(not my boat in pic)

Raised the dagger board to shmear marine tex discovered damage to the trailing edge from top to about 2 feet down???? Shmeared that too. Makes me wonder if the board has been damaging the aft part of the sheath.

I seriously doubt it. The daggerboard trunk is way stronger than the board. It's solid epoxy, glass, and sand ballast at the trunk foot. The board is designed to break easily to prevent damage to the boat.

Yeah - rock solid, that trunk. Literally. Hit it with a soft hammer next time you're under there to quell your fears about it.

Wild guess here... Some damage might be the result of excessive enthusiasm when raising the DB (= "daggerboard hammer"). The upward inertia keeps the DB moving past the point where you want it to stop and slams into the bottom of the (solid) mast and mount. Partly dependent on how much water has drained from the DB in that time.

The damage to the trailing edge of the top of the DB is the (predictable) result of the small contact area between it and the DB trunk. That results in a very high psi concentrated along a very small surface area. To reduce it I increased the diameter (and contact area) to 3/4" , with a short length (~12" so it never enters the slipstream) of PEX glassed in for less friction when I bought the boat. It's another Achilles heel that is just the nature of the beast. (Not just Macs).

-Brian.

Same damage here, Plan on putting a few pieces of adhesive foam on the top to buffer from smashing into the mast foot.

Bob, If you put the knot on the daggerboard line no need for adding foam..Works great

but then i'd have to drop the mast again

Didn't think about that...try using foam

Or you could do nothing and just raise the DB with less enthusiasm.

It occurred to me Bob (OP) that if your damage is similar to that in Matt's picture above that it could also be caused by extending the DB too far. It should extend no more than 5 feet beyond the hull bottom, leaving one foot of contact inside the trunk.

Any more than that would cause damage that might fracture backwards along the top edge (maybe, or maybe not from striking an object or bottom), and would be accompanied by witness marks that would show on the trailing edge some distance less than 12” from the top edge.

Of course the preventive measure to take for that is to make sure that the position of the stopper knot on the line prevents the DB from extending more than a foot.

My DB would only come up with a fight due to the washer binding on the line. I gave the DB line a good soaking of that sailkote and it’s really smoothed things out. I’ll still put the foam in, but I think now that its operating better the smashing into the mast foot will be reduced? Time will tell I guess.

Doesn't the washer stay at the knot, Bob ? My memory fails me.

Ya the washer slides on the rope and locks against the knots. But the washer tends to bind against the rope sometimes as I’m pulling it up. I think it hits the deck and turns sideways then hits the block and jams up. Now it seems to slide much easier with some sailkote on it.