Mast deck compression

[Chris]

I bought my 1975 C27 over a year ago and at the timenoted (along with my surveyor) some modest compression on the deck in the mast area. The surveyor assured me that this was fairly common and told me that I should monitor this but not worry. The boat was in such good shape in every other way that I bought it and I'm happy I did. There has been no visible change in the deck compression and I have no other signs of problems--leaks, cracks in the headliner, etc. My questions:1) How common is this compression problem?2) Should I be deeply concerned?3) What actions can I take, if any, to rectify this problem?

 

[Mike Turner]

Common Problem

I have similar deck compression on my 81 C30, and my surveyor said much the same thing. It's caused by either softening of the plywood strengthener/ core under the mast, or overtightening of the rig, or both. Practical Sailor routinely noted it in most used Catalinas they reviewed. You should watch for cracking of the deck and interior cabin liner as signs of problems, as well as leaks. Be sure to also check the compression post in the cabin and the compression block under the post in the bilge if it's accessible for softness. Catalina has a good sheet on the repair -- basically you remove the mast, use a hooked tool to pry up the compressed deck, and fill underneath with epoxy. Contact them to get the sheet. I plan on doing the repair when I change the standing rigging this year or next. Good luck and good sailing!Mike TurnerS/V Amity

 

[Steve]

Another way to go

I also have a 1981 C30 with a pretty good dip under the step. It is being fixed by an expericned yacht glass guy (Team Yachts in LA).He is charging me about $200 to do the job. Here’s what he’s doing.1. Take the mast down (it was down for SR replacement)2. Grind the glass off an area approx. 6" by 6" under the mast. This exposes the plywood so you can assess the extent of the damage.3. If there is rot in the wood, cut it out, making sure not to damage the cabin ceiling. 3a. Or, if there is no rot but the wood is wet (like mine was), soak the area with acetone. As the acetone evaporates, it will draw out the water. Repeat this step daily for three days (or how ever long it takes to get very dry wood)4. If the wood was cut out, replace it.5. Impregnate the wood with the proper type of resin.6. Apply glass and gel coat to match.The guy that is doing mine, says that he's done several other C30s like this. I like his approach much better that the quick fix recommended by Catalina. The disadvantage is that it will take a pro to match the gel coat.Someone recommended that gel coat imperfections can be hidden by mounting a wing plate (aka halyard organizer) under the mast. My rigger advised against this because the electrolysis (SS against aluminum)will cause the mast and mast step to corrode when the plastic gasket thing wears out.

 

[Roger]

Look for other compression

I have a 74 C27 and there are at least two other areas of compression near the windows on starboard. Unless they get worse, the yard told me that the cost to repair is pretty steep. If you have found one area of compression keep your eye out for other areas.

 

[Peter Hine]

The mast step electrolosis is easily avoided...

When I did my mast (74 C27) about 6 years ago, I wanted the deck organizer, and had a little compression to remedy. I put the organizer on the deck, put a thin (I think maybe 1/4") piece of lexan between the SS organizer and the aluminum step. No corrosion so far after 6 years. I plan to drop the mast this fall for a thorough look-see underneath everything, but expect to find nothing...Good luck!