28
Cruising Helmsman July 2018
due to crevice corrosion. Stainless steel
needs oxygen to form a passive non-
rusting surface. In places like where the
chainplates pass through the deck, oxygen
is unavailable but, if the metal is not kept
dry, crevice corrosion can occur.
This is the most common reason
chainplates fail. Chainplate failure usually
equates to dismasting, so you need to take
it seriously.DECK
Whether or not the boat has cored
construction in the hull, the decks of
post 1970s boats will most likely be
cored with either foam or end-grain
balsa. These should have solid areas
where hardware is attached, so look for
any add-ons or any sign of the fastenings
crushing the deck.
One way to tell if you are dealing with
a cored deck is to look underneath, at the
area where it meets the hull. This may only
be visible inside lockers, especially the
cockpit lockers.
On most cored decks, you will see a
step where the laminate changes from
solid fibreglass near the outer edge to the
thicker cored area. You may also be able
to tell by looking around ventilators and
hatches, although these usually have a
trim piece to hide the cutout.
Any deformation or leak is a point of entry
for moisture to travel within the structure.
Does the deck f lex when you walk on
it? You may be able to see leak points
from below, but the best way to check
for soft spots is by tapping gently with
your small hammer. If you practice this
beforehand, you will be familiar with the
difference in tone between solid and soft
material. What matters here is the change
in sound, rather than becoming expert
at knowing exactly what the hammer is
telling you.
A soggy deck (or hull if the hull is cored)
could mean expensive repairs. This can be
a deal breaker when the cost is deducted
from the asking price.
While you are on deck, check all the
lifeline stanchions, pulpit and pushpit
for cracks and general security. Look for
depressions where a stanchion base has
been pushed into the deck, potentially
allowing moisture to enter. If the stanchion
bases are cast aluminium, check for cracks
where the stanchion enters.ABOVE: This old
Compass presents well
in the initial dock view.
RIGHT: In this photo
I am at the top of a
30 metre mast.
BELOW: The same
mast, same camera,
same time, from dock
level, using a hand-
held camera with an
excellent telephoto
lens. We see amazing
detail, but cannot know
what we are missing.COLIN BELLCOLIN BELL