Mast step fault

[macafity]

I have a problem around the area of the mast step on my boat its a mystere 26 MK2 year of build approx 1976. I think the bolsa core under the mast step is starting to collapse If indeed it is a bolsa core. The deck sinks by about an inch in an area about ten inches across. I would be grateful for any ideas on how to tackle this problem.

 

[Talbot]

welcome to the forum.

The most important thing to establish is whether it is indeed a cored deck, and over what area is there a problem. The method to do this will depend on how confident in D-I-Y you are. Persnally I would be getting a boat builder to have a quick days worth of effort to establish the size of the problem, the best way of rectifying, and cost/viability of this.

 

[geaves]

Had a similar problem on my boat.. Took advice from the boat yard and had them carry out the work... V. expensive i'm affraid.. You could be looking at £2k+ ... Sorry!!

 

[Pye_End]

What support is there underneath the deck? Does it have a bulkhead or a separate support? Need to check that whatever is there is sound before assuming it is simply the deck.

 

[tome]

It's very common on deck stepped masts, specz with an older boat

Highly unlikely to be a balsa core, more likely ply. It's 30 years old now and will be waterlogged, probly with rainwater rot so crushing slowly. Mast has to come out to fix it, but thereafter it's not a big job to cut away and replace

 

[Avocet]

Had exactly the same problem on mine. The cabin roof is single thickness GRP but immediately under the mast foot it is double thickness with a plywood infill about 2' long and 6" wide and 1/2" thick. I put a hole saw through the inner skin from inside the cabin in a few places to see what was going on and found the wood was very soggy. After I'd cut away the inner GRP skin, most of the plywood came out with a tea spoon! I ended up just laminating solid GRP into the space that was left, up to the same thickness as the plywood. To be honest, if I was doing the job again, I'd cut the top skin away and work from above - it was a foul job working upside down and the boat got completely full of dust! I'd probably also use epoxy rather than polyester resin and maybe use some sort of "coremat" type sandwich filler rather than solid laminate but what I've ended up with seems to be working fine now.

 

[macafity]

Many thanks for info David

 

[woody001]

Make sure the boat builders jack the deck up BEFORE doing the repairs, a common mistake they make.

 

[Lakesailor]

I had a deck head collapsing on my Foxcub which was the whole cabin roof and support beam. I made and installed a mast compression post which is adjustable. I used a core bite in my drill to establish the condition of the deckhead. As it turned out it was resin infill.
If you need to replace the infill beneath the mast step to bear on a compression post or bulkhead I would suggest a car fibreglass repair paste which consists of a resin paste with chopped glass in it. It's easy to work and form and cures to form a very rigid pad.
If you want to look at the pics PM me.