1985 H31 Mast Support Beam

M

morich

.
Aug 21, 2013
13
Hunter 31 Patchogue
Can anyone tell me whether the molded mast support beam running across the cabin top has wood or metal under the fiberglass shell?
I am getting water dripping from the light fixtures on both sides and can only assume the water is coming from the mast deck plate. I am hoping it's aluminum and don't have wood rotting inside there, but I have my suspicions. The previous owner replaced the vertical mast support beam prior to my purchasing the boat. One less thing to worry about.
If there are any fixes for this problem without dropping the mast I'd appreciate hearing about them. Thanks!
Rich P.
 
Allan12210

Allan12210

.
Jan 22, 2008
1,667
Hunter 34 Alameda CA
morich said:
Can anyone tell me whether the molded mast support beam running across the cabin top has wood or metal under the fiberglass shell?
I am getting water dripping from the light fixtures on both sides and can only assume the water is coming from the mast deck plate. I am hoping it's aluminum and don't have wood rotting inside there, but I have my suspicions. The previous owner replaced the vertical mast support beam prior to my purchasing the boat. One less thing to worry about.
If there are any fixes for this problem without dropping the mast I'd appreciate hearing about them. Thanks!
Rich P.
Click to expand
Starting at the deck just under the mast plate is a fiberglass skin. Then there is a 1/4" aluminum plate followed by maybe 3/4" of synthetic high density material and a final 1/4" fiberglass. Then you are inside the beam (it is a three sided construction as part of the overhead liner. Inside the beam (unless changed by a previous owner) is a piece of 4 x 4 Douglas fir that is prone to rotting or compressing under the load of the mast.

The source of the water is probably around the piece of PVC pipe that is stuck in the hole in the deck extending a few inches up inside your mast (standpipe) that the wires pass through. If the caulking has failed then water can seep in around that pipe. Alternatively, if the wires don't have a drip loop in them before entering the standpipe, and it is not adequately sealed with caulk, then water can enter that way as well.

Either way, it is really hard to re-seal that with the mast in place.
 
M

morich

.
Aug 21, 2013
13
Hunter 31 Patchogue
"Then there is a 1/4" aluminum plate followed by maybe 3/4" of synthetic high density material and a final 1/4" fiberglass. Then you are inside the beam (it is a three sided construction as part of the overhead liner. Inside the beam (unless changed by a previous owner) is a piece of 4 x 4 Douglas fir that is prone to rotting or compressing under the load of the mast."

I just want to be sure we are talking about the same area.
The Douglas Fir... it runs horizontally across the boat's beam between the cabin liner and the fiberglass deck, correct? If so, how does one check to see if the wood is rotted and if it is, is there a repair proceedure? Thanks!
Rich P.
 
Allan12210

Allan12210

.
Jan 22, 2008
1,667
Hunter 34 Alameda CA
morich said:
"Then there is a 1/4" aluminum plate followed by maybe 3/4" of synthetic high density material and a final 1/4" fiberglass. Then you are inside the beam (it is a three sided construction as part of the overhead liner. Inside the beam (unless changed by a previous owner) is a piece of 4 x 4 Douglas fir that is prone to rotting or compressing under the load of the mast."

I just want to be sure we are talking about the same area.
The Douglas Fir... it runs horizontally across the boat's beam between the cabin liner and the fiberglass deck, correct? If so, how does one check to see if the wood is rotted and if it is, is there a repair proceedure? Thanks!
Rich P.
Click to expand
Yes, that piece of wood (about 2 feet long) is horizontal. The best way to get just a small peek at it is to remove the door to the head. Then the cover over the front of the compression post (the door jamb) can be removed after popping the plugs that conceal the screws. You will be able to look up through where the wires are coming down out of the beam.
 
Last edited:
Scott

Scott

.
Sep 24, 1997
242
Hunter 31_83-87 Middle River, Md
Most likely, both the compression post and cross member are rotten and have to be replaced. Been there done that, lots of info in the archives. I'll try to upload some pics of repair. I have the pics, but don't have a clue as to how to upload them.
 
M

morich

.
Aug 21, 2013
13
Hunter 31 Patchogue
Thanks! I would appreciate that. As I mentioned... The previous owner replaced the vertical beam. I see a spot where the horizontal cross member is cracked but I assume he did it when he was jacking up the cross member to replace the beam.
Again, I would appreciate any info on this subject. Thanks again!
 
kloudie1

kloudie1

.
Nov 6, 2006
10,104
Hunter 34 Mandeville Louisiana
Mast Support Beam

Tons of info in the H-34 files. The 31 and the 34 both have that Achilles Heel .. The crack is most likely the compression post punching up into the horizontal beam. The wood inside the horizontal beam rots and then nothing is there to resist the compression of the mast, so the compression post cracks the horizontal beam.. Allen and Scott covered it pretty well.
Picture is looking at the place where the compression post would normally be. It has been removed and a hole the exact size of the post was cut in the bottom of the beam. My cross beam had collapsed enough that the little PVC conduit was trying to take the compression load. It had split and the caulking had failed. Not an easy job but it is straightforward.
 

Attachments

You must log in or register to reply here.

Top Bottom