Question about Mast compression???

[Bob Haskell SV Blackmist]

On our 30'78 Hunter the standing rigging has slowly become lose and water seems to stand at the base of the mast.The compression post assembly resting on the forward area of the keel seems intact,going vertically from there to the what appears to be a healthy header that goes horizontally on top of the compression post assembly looks as it should.Having said that, all thats seems to be left as the culprit is the area between the top of the header and the underside of the overhead fibreglas/sandwich/fibreglass.After that it appears to be the mast reciever and the mast itself.Now for the question...Is that infact a sandwich makeup that the mast sits on,and what in your opinion is the best way to cure this problem.We have had this boat for two years and really love everything about her,except maybe some of the minor problems we have experienced,still a great boat!!!Please help................Bob and Lynda SV Blackmist Ketchikan,Alaska

 

[Brett]

Deck Compression Under Mast

Our 1978 H30 suffered from the same problem. The core in the deck under the mast had water intrusion and subsequently started to compress. The remedy is to remove the mast and the mast step, remove the top skin of the fiberglass and replace the core. A new top skin is then layed over the new core, a little gel coat and voila, like new. It was not something I was interested in doing, so I had a reputable yard handle it. The repair was excellent, and can not even be detected. I can't remember the cost, as I had other work done at the same time. When you fix this, it will give you an opportunity to thoroughly inspect the rigging too.

 

[Roland]

Deck compression

I concur with Brett about this. I just had my mast pulled and the deck step cored out and rebuilt. Just yesterday, I had the aft cover of the compression post removed to inspect for damage. The post is a 6x6 piece of douglas fir. Very strong. Water had migrated down the wires and infiltrated the post from the bottom up about 8 inches. Also infiltrated the bulkhead between the saloon and the head. Am going to look at replacing the bottom of the post. Check the archives for further info.-RolandS/V Fraulein II '77 h30

 

[JC 2]

Apology from junior design team member

Re: deck compression under mast.Guys, I would LOVE to blame Hunter on this one though I know my father should have insisted more strongly. For a reputable boatbuilder to stand the spar on ANY deck material other than SOLID fibreglass is entirely unacceptable. There is simply no excuse for this. Solid 'glass will not compress, being liquid in nature and having nowhere to go.If anyone is repairing this, ensure that the square foot or so upon which the maststep is mounted is redone with fabmat or the modern equivelent and is solid glass. NO coring material such as foam, balsa, etc., should ever be used there. I know my father would have specified this and it was probably just Hunter cheapening the product again or just not realising how crucial it is (remember they were a motorboat manufacturer first).In our Raider 33 we had a very sweet square-section aluminium compression post with a flange at each end. The maststep fitting was bolted through the (solid glass) deck to it and the bottom end stood on the keelson to which the lead was bolted. It was like a rock. I have NEVER heard of a Raider maststep needing anything other than caulk, as opposed to problems with H-27s and '30s I have seen. If at all possible look into spending $300 or so and having a metal one made once and for all. Just make sure to add 1/2" or so to your best measurement to account for deck sag, etc.JC 2

 

[Bruce]

Repairing Deck Compression Myself

JC2,I am renovating an '80, H30 with the deck compression problem stemming from water intrusion. Using a grinder with a cut off blade I cut out the interior of the raised mast step 1" in from the edge al the way around and removed all the rotted core (plywood). Then I cut through and removed the core (balsa)from the next layer down. This leaves only the cabin top layer. My plan is to fill the cavity and place a 1/4" aluminum plate over the raised mast step formation. Since I left 1" all around the edge I plan to chamfer and place the Aluminum plate edge 1/2" from the edge. I'll secure the plate with 5200 and the bolt through from the mast step. What do you think of this plan overall and what about filling the cavity with long strand structural filler?