Unknown Part and function

[Jimc91]

New question for forum experts.
The 2x4 wood mast support will need replacing as one side is a bit soft.

Regarding removal of this board is the board end secured to deck with thru-deck fasteners from top deck. In the photo you can see the mast support bracket bolts do not penetrate the board.

Replies appreciated.

 

[dLj]

New question for forum experts.
The 2x4 wood mast support will need replacing as one side is a bit soft.

Regarding removal of this board is the board end secured to deck with thru-deck fasteners from top deck. In the photo you can see the mast support bracket bolts do not penetrate the board.

Replies appreciated.

I don't have any idea of the answer to your question.

However, i'd recommend you start a new thread with this question. It will get more eyes on it.

dj

 

[jssailem]

The board looks to be a compression post to support the deck stepped mast.

A lot of adhesive caulk appears to have been applied to the location under the mast. I suspect there has been a leak, based on the rust stains. If the deck is cored than likely there has been water intrusion.

Remove mast. Remove compression post. Remove all hardware at mast base. Correct deck fiberglass. Inspect compression post base. Repair if needed. Replace compression post. Position beneath mast. Reassemble deck hardware. Reinstall mast. Go sailing.

A basic plan.

Is the compression post secured? It likely was at one time. It may have been a tight fit with some adhesive caulk. It may be screwed in from the top to the deck. Impossible to tell original structure.

 

[rgranger]

Since you are going to replace it anyway, you could just cut the post and then see how it is secured. Have you removed the tabernacle to see what is above your post on deck?

 

[Jimc91]

Yes, I know what is above: the Mast is within a few inches hence my comment that bracket bolts do not intersect with this support post and the other small bolts are fasteners for a halyard fitting. The caulking will be replaced at time of the repair.

The post appears to be a lamination of different woods. I considered Pressure treated wood but that seams a bit tacky so I will check some specialty lumber stores and see if there is something more esthetic and affordable.

Though the deck mounted mast is lightweight (the inner structure might use a bit idle stiffening) I was considering creating a wood frame or bulkhead partitions to run full width of inner cabin to reinforce the deck/mast loads and fiberglass it to the hull. Loosing a little cabin space did not bother me.

Thank you for your reply

 

[jssailem]

I would remeber that this is a "compression" post for a 17ft sailboat. Making sure that the deck is solid, and that the post is in contact directly beneath the mast base and the keel is important. You do not need a 4x6 or steel girder. I suspect a 3x3 laminated post will be more than sound to transfer the force on the sail to the keel. You might add a layer beneath the deck if it is currently springy. I would make sure all of the through bolts and screws are properly potted using the technique identified in this link for the holes. Rebedding Deck Hardware With Bed-It Butyl Tape - Marine How To
It will assure you that water ingress will be stopped.

 

[Jimc91]

My latest findings.

The damaged compression wood post bottom sits is a very slight pocket formed in the FRP seating bulkhead, at an angle, and there is one small screw up thru the fiberglass bulkhead into the post bottom as well as lots of adhesive sealant as seen in photos. This being a deck mounted mast and its wood compression post only bears on the interior cabin bulkhead and not directly on the keel in the center line of vessel, as the upper deck and interior cockpit bulkheads carry the load to the hull but not directly to the weighted fixed keel.

There is adhesive around the base of the compression post, as well as, at top seen in photos, maybe it is glued in place? I have not found any evidence of a screw or fastener from above, thru the deck, as all fasteners are accounted for, but I will know more when the board is cut out. I plan to replace the damaged compression post with a piece of zebrawood I have which is harder than teak or white oak but it will be interesting to see how it is fastened to structure.

The bolts for the mast support bracket are most likely the source for the water damage to the post and I will take measures to prevent water entry from the mast bracket screws. As best I can determine the deck is constructed of solid fiberglass and not "cored". The fiberglass ranges in thickness from 1/4' to 3/8+" in the radius corners.