Cabin Deflection

[rich26nc]

Had some well meaning friends help tune my rigging. Now the cabin top is deflected at the mast step. I will loosen the shrouds as I believe the deflection is caused by the shrouds contracting during a recent cold snap. The fiberglass on the deck and in the cabin shows signs of cracking. Any suggestions in the event the cabin does not return to its original configuration?

 

[woodster]

you could have other problems other than cold weather contraction ...your deck could be soft in the core ....your base at the bottom of your compression post could be soft or water logged ....and your compression post could very well be rotting at the bottom as well ....check all those things first ...and there is a possibility that you have the rigging to tight but you would have really had to crank down on those shrouds to cause that ...cold weather contraction is very minimal on the wire rope in most cases

 

[kloudie1]

Deck core soft or compression post as Woody says.. Aluminum shrinks more than stainless with cold so shrouds would be loosening as things cool and tightening as things warm.. The effect is small, because their growth/shrinkage behavior is very nearly the same..
Example.. on a 30 foot mast, with a 30 F change in temperature, the difference in contraction is about 0.024" or a bit less than the thickness of a credit card.. or about a half turn on the turnbuckle. (assuming 24 pitch threads..)

 

[Brian S]

I have noted my rigging going slack this season. I had it all tuned in the spring, then noted in August it seemed loose. So, I tuned again with the Loos gauge, and by October it seemed loose again. That's when I felt definite sinking in the deck at the forward corner of the raised mast step. Another guy I know with a 222 speculates that water comes in through the mast step bracket holes, because many O'day have fine cracks in the gelcoat along the deck to raised step joint. This spring I will have to remove my compression post, pull back the cabin liner, and see what I can find out from up underneath. I figure it will be easier to hide repairs from under the liner than if I were to cut out the mast step from above. Come to think of it, I should be cutting this stuff up now, before the super freezing happens. Sigh, the joys of owning a 30 year old boat designed to last through only one owner...

 

[kloudie1]

It is a fairly common thing to have happen, Brian.. Look under the Hunter 34 info and search on "compression post" .. I did mine from underneath for same reason as you are stating.. It is a fairly big job, but the toughest thing about it is deciding to just do it.

 

[centerline]

I agree with all the above... the "well meaning friends" may have properly tensioned the rigging, so it would sail, but the deck or compression post may be failing... and it may not have been apparent at the time it was tensioned, as these kind of failures commonly show thenselves while under sail, or after it sits awhile...
loosening the rigging may save further damage short term, but it isnt the answer to the problem.... the boat cant sail well with loose rigging, so the actual cause will have to be found and repaired.

 

[Brian S]

It is a fairly common thing to have happen, Brian.. Look under the Hunter 34 info and search on "compression post" .. I did mine from underneath for same reason as you are stating.. It is a fairly big job, but the toughest thing about it is deciding to just do it.

Thanks for the vote of confidence, Kloudie! I also have some pictures from Rick Kane, who did a great job of fixing core from inside on an O'day 222. I'm loathe to cut up the deck, and then have to deal with non-skid areas, painting, etc...

 

[rich26nc]

QUOTE="rich26nc, post: 1257291, member: 127212"]Had some well meaning friends help tune my rigging. Now the cabin top is deflected at the mast step. I will loosen the shrouds as I believe the deflection is caused by the shrouds contracting during a recent cold snap. The fiberglass on the deck and in the cabin shows signs of cracking. Any suggestions in the event the cabin does not return to its original configuration?[/QUOTE]
Thanks to all of you who responded to my query. Core compression is likely the culprit. I did a recent repair on my keel tube housing the dagger board line. First fiberglass project and it is strong. Thinking the solution to a compressed cabin top is to have the area around the mast cut out from above or below and repaired with several layers of fiberglass and tie it back to the cabin topsides to distribute the load. That, however, will require the services of a professional.