Mast Wedge Wood Type?

[AJ_n_Audrey]

Originally Posted by Flatswing

IPE aka Ironwood

https://ipewoods.com/

[BAD ORCA]

Originally Posted by wingssail

I gave up on wedges years ago. They would work out and allow the mast to move around in rough weather.

Replace wedges with plywood plates.

My solution will work if you have, like I do, a rectangular mast collar which is an opening in the deck for the mast. It is a box of aluminum plate welded up, and it actually protrudes up from the deck about an inch and it is some what bigger than the mast, on all sides.

I made marine plywood plates, about 3/16, that slip in between the mast and the aluminum box walls. The plywood plates have "ears" at the top so they cannot fall down.

I pull the mast forward with the a halyard (shrouds loosened) and put in plates in back of the mast. Then I pull the mast back with the main halyard and put in plates in front. Side plates I just drive in with a light hammer. In this way the mast is held in position. You can vary the number of plates in front or back to adjust prebend in the mast. When I am satisfied with the mast tune I lock the plywood plates with screws drilled through the aluminum into the plates but not into the mast. Because of the ears and the screws they will not fall out.

Sealing to prevent water ingress:

Since the mast collar protrudes up from the deck about 1 inch I am able to wrap a layer of neoprene around the mast and clamp it tightly with long hose clamps both to the mast collar and the mast itself up about 6" (after previously filling the mast track groove with a gob of silicone sealant).

Then I have sewed a sunbrella boot for sun protection which goes around over the whole thing and extends a few inches higher than the neoprene. It has velcro to hold it and a tight bungie at the bottom and top. A band of neoprene at the top, inside the boot further seals the assembly.

Benefit

The type of mast boot holds the mast in position, won't fall out, and keeps the water out and protects the velcro. It is also removeable and reusable and adjustable.

interesting idea but my mast 'collar' is and ovalish shape. I took a peak from the inside of the boat this weekend and stuck a butter knife up into the rubbery substance surrounding my mast. it turns out there is NO mast support at the deck at all except a heavy 1/2" thick bead of silicone caulking.

you gave me an interesting idea though. i think for this haulout im going to go with wood wedges. im not doing any offshore sailing aytime soon so they should be ok for a while.

when i have the mast out this haulout, im going to make a perfect template of the inside of the opening that goes through my deck and a perfect template of the outside profile of my mast. i'm going to use those templates to create a CAD file to CNC machine a perfect insert from 6061 aluminum. it will go around the mast and insert into the opening. i'll machine a wide flange that allows me to secure it to the deck and i will also incorporate a caulking groove into it at the mast itself. on my next haulout in a couple of years for paint, i'll unstep the mast and give it a try. i will need to use the wedges though on this haulout so i can grab measurements of where the mast rests in the deck cutout so i can use those for the aluminum support.

[wingssail]

Originally Posted by BAD ORCA

...i'm going to use those templates to create a CAD file to CNC machine a perfect insert from 6061 aluminum. it will go around the mast and insert into the opening. i'll machine a wide flange that allows me to secure it to the deck and i will also incorporate a caulking groove into it at the mast itself...

Just make sure that the insert has a wide surface where it touches the mast, not an edge, so that it spreads the load and does not cause a dimple in the aluminum mast when pressure due to waves or rig tension is applied.

Also you might consider making it in two halves so that it can be removed without un-stepping the mast.

[AndyEss]

One thing to keep in mind as to wedging a keel stepped mast at the deck for structural support is whether or not the deck is designed to be stiff enough to provide adequate lateral support to make much of a difference. From memory, column (mast in perfect compression) strength is inversely proportional to the cube (3) power of its length, so deck lateral support can have an appreciable good effect on lessening the failure of a mast.
That is only if the mast partners (the deck where the mast passes through) has been especially reinforced to provide this substantial lateral stiffness.
Bad Orca - if your mast has performed without failure in all the years the deck hasn’t been structurally tied to provide lateral support, I would guess that your new project is overkill.
Check with the original boat designer. You may even make things worse by rigidly tying the mast to a more flexible deck and induce the deck to start cracking around the mast.

[BAD ORCA]

Originally Posted by wingssail

Just make sure that the insert has a wide surface where it touches the mast, not an edge, so that it spreads the load and does not cause a dimple in the aluminum mast when pressure due to waves or rig tension is applied.

Also you might consider making it in two halves so that it can be removed without un-stepping the mast.

thats interesting i could do that. i could machine it a beefy tab and thread two halves together with heavy machine screws. that would allow me to try it sooner. the only thing i may not have time to do though is fair the inside of the opening so the sleeve fits precisely. i'll think of something.

yes definately. it looks like my boat builder made a pretty heavy duty area where the mast goes through the deck. its about 3" deep and really smooth side walls. I would make the collar so that it inserts almost the full depth.

[BAD ORCA]

Originally Posted by AndyEss

One thing to keep in mind as to wedging a keel stepped mast at the deck for structural support is whether or not the deck is designed to be stiff enough to provide adequate lateral support to make much of a difference. From memory, column (mast in perfect compression) strength is inversely proportional to the cube (3) power of its length, so deck lateral support can have an appreciable good effect on lessening the failure of a mast.
That is only if the mast partners (the deck where the mast passes through) has been especially reinforced to provide this substantial lateral stiffness.
Bad Orca - if your mast has performed without failure in all the years the deck hasn’t been structurally tied to provide lateral support, I would guess that your new project is overkill.
Check with the original boat designer. You may even make things worse by rigidly tying the mast to a more flexible deck and induce the deck to start cracking around the mast.

thanks AndyEss. food for thought. the manufacturer is long out of business but there is an active owners group. i'll ask around to try and verify.

i didnt have time to remove the boot from the outside last weekend to get a look from the top side. i will do this this weekend and try and determine whats going on and if its a previous owner fix or original.