The single removable mast on our 26 foot sail boat is stepped onto a metal
fitting on the fibreglass deck.
The metal fitting (mast step) allows limited forward/aft positioning of the
base of the mast.
A stainless steel column below deck takes the weight/compression down to the
keel.
Below the metal fitting is a wooden block, or backing plate, about 16 inches
by 12 inches and about 1.25 inches thick. The wood is held in place** and
covered by fibreglass. Originally the wooden blocked presented a smooth bump
or raised area of the deck around the base of the mast.
Several winters ago the wooden block got wet* and then froze (during our
Canadian winters!); this caused the wood to expand and burst/crack its
surrounding fibreglass encasing, so we had to remove it. The deck itself is
undamaged.
The original wood which looks like a piece of scrap mahogany or similar has
dried out and returned to it's original shape and size but it seems somewhat
grainy and still a bit soft due to the ice damage? So if reused it might
compress slightly.
So thinking of replacing; with what? Although, hopefully, this time water
will never again get in there! See *
Been advised not to use oak. I have and could use some good quality spruce
or fir which although soft wood is dense and strong. Also could use several
layers of marine plywood thus making it possible to able to obtain an exact
thickness by combining layers.
The block has slightly tapered sides; it is not quite a standard lumber
thickness so will be necessary to hand plane or run the block of choice
through a thickness planer.
Freezing*! The reason the water got into the wooden block was that some
years before we acquired the boat the mast was replaced and holes for new
mast wiring were drilled through the fibreglass and wooden block. New
'marine' sockets into which to plug sockets from the mast wiring had been
installed. Although the sockets were in a suitable location they allowed
small amounts of water to percolate down into the wood which then froze!
This sounds like a similar problem to when water gets into balsa cored boat
decks etc. Our future wiring will not go through the area with wood even if
this means taking other measures to get the mast wiring, VHF antenna coax
etc. below!
Fastening mast step 'through' the deck? ** As originally built the bolts
that hold the mast step go through the wooden block (which was then encased
in fibreglass) but not through the deck. One idea is to put stainless bolts
right through the whole thing with nuts on the bottom end of the bolts up
against the toilet/head compartment deckhead below?
But maybe there is a good reason for not doing that? In other words if the
mast and its step were ever torn off the boat damage to the deck might be
minimized if the bolts do not go right through?
Any comments or ideas about best way to proceed would be most welcome. TIA
Terry
>> Stay informed about: Replacing wooden board under mast step on sail boat.