Article first published Tuesday, 5 August 2008 on the original hawk20.net, now moved to this site.
Leaking lockers seem to happen at some stage on all Hawk 20s whether old or new. What is the root
cause? Probably not any single factor, but a combination of the
inaccuracy of the mould used to make the locker upstand, and the thinness of the sealing strips used under the
locker lids. A friend who owned and raced one of the very first Hawk
20 day boats in the early 1990s had the same leaking lockers. When he
looked at our Hawk he found the problem still existed. Its possible
that the problem may have been cured on cabin boats as a new mould
will have had to be made for the locker upstands and cockpit, but I
don’t have any definitive information for this.
The starboard
locker is the side where you first notice the problem. It appears the
upstand of the locker lip is not high enough to make a good
watertight seal against the installed seals. Water
enters the locker when the gunwales go under, or a wave comes over. A
locker full of water slows the boat down, hampers handling, can
contaminate your fuel if you leave the breather open, and if you kept
dry clothes in there, consider befriending damp dogs you meet.
Several people
have come up with solutions to this thorny issue:
1) Either remove
Reid Marine’s existing sealing strip and refit thicker strips.
Starboard on a day boat seems to need 19mm (could be different for
new cabin version moulds), whereas port uses 16mm.
2) Or, run
a bead of silcone sealant around the locker upstand to fill the gap to the
existing rubber strip.
3) Or, some success is reported using
tap washers between the hinge and top surface of the locker so the
lid is further depressed and the existing sealing strip presses more
firmly against the locker lip upstand.
If leaking lockers
are caused by mould inaccuracy, this will probably continue until the
existing mould reaches the end of its economic life. CML(Composite
Moulding Ltd), who make the hull, will then have to make a new mould
and hopefully take the opportunity to increase the height of the
locker upstand. Alternatively Reid’s could take a pragmatic view
and fit thicker seals.
In terms of cost,
the cheapest solution is the tap washer trick. The bead of silicone
sealant is the next cheapest costing a tube of sealant (£8), a roll
of masking or electrical insulation tape, Methylated Spirit for
cleaning, and pence for the Vaseline. Finally the most expensive is
to replace the strip, which costs £30 for good quality self-adhesive
neoprene strip, plus acetone for degreasing the surface of the lid.
The
bead of silicone sealant. Solution developed by David Mellor.
Although the
starboard side is by far the worst, both lockers tend to leak badly
in my experience if a wave comes aboard.
Incidentally,
before I forget, it is best to seal all four standing sides of each
locker because if the cockpit fills up water enters the lockers under
the front of the lids as well as more usually under the sides and
back of the lids.
After
experimenting with various sealants I have found that the best one
for the job is marine silicone rubber not least because it will set
when exposed to Vaseline.
The
procedure/method is as follows:
1) Wash the
existing seals (on the lids) and the standing surfaces of the lockers
with fresh water and allow to dry completely.
2) Cover the
existing seals on the locker lids with 3 cm wide good quality masking
tape e.g. 3M.
3)
Clean the standing locker surfaces with Methylated spirits and allow
it to evaporate.
4) Coat the
masking tape, covering the lid seals, with a thin layer of Vaseline.
5) Load a 310 ml
tube of white marine grade silicone rubber into a sealant gun and put
a 10 cm long 1 cm thick worm of silicone onto a piece of wood or
cardboard. This will be your reference piece to check how quickly the
silicone is going off.
6) Apply a 1 cm thick layer of silicone on the standing parts of both lockers making sure that the silicone will be clear of the lid inner edges when the lid is shut.
7) Let the silicone partly cure so that on pressing that which has been applied to the wood /card board it does not stick to the finger or burst. Shut the lids and keep closed for 24 hours.
8) Allowing the silicon to partly cure before closing the locker lids for the first time enables the sealant to retain some bulk so that it is not flattened too much when the lids are shut for the final curing process. The silicone will then provide a better seal. However, if the silicone is allowed to cure for too long before the lids are closed, the locker catches will be under too much pressure for comfortable use when the curing process has been completed.
9) Lift the lids,
remove the masking tape and trim off the surplus silicone with a
sharp knife.
After the
resealing, it maybe thought that the masking tape and Vaseline were
not required. This would be the case if the partial curing has been
judged correctly but on each occasion when resealing lockers, having
now done the job on Hawks owned by four friends, my nerves have not
been strong enough to risk it.
Editor note: Seems
very sensible to put some release agent on the tape so the silicone
sticks firmly to the upstand and not the lid. I tried this solution on a friend’s Hawk and am impressed with
the simplicity and speed of the fix. The locker has stayed dry in wet races, i.e. F5/6
Replacing
the locker sealing strip. Used by many in Christchurch.
These notes are to
help you replace the seals under the locker lid. This method was
first tried out on sail number 189 in 2002 and has worked solidly
over seven seasons.
When I first
started looking into this and doing my own lockers, the material was
only supplied in lengths “not quite long enough to do a locker”.
This could have changed in the last year as I have not had to help
with any other Hawks recently. Nominally you need 2.64 metres of 40mm
wide strip for each locker, so you had to buy two rolls per locker.
The best way to keep the cost down to £30’ish per locker is to
team up with other Hawks that need the mod.
I suggest you buy
strip that is 40mm wide as the locker upstand on the hinge line
exerts a side load on the sealing strip as you close the locker. You
don’t want the strip to be pushed to one side. Note the starboard
locker requires 19mm thick strip, whereas port requires 16mm thick
strip. If you try 19mm strip for the port locker, it will not close.
Since the
manufacture of the cabin version the cockpit mould appears to have
changed, as the 19mm sealing strip was too thick and a locker lid
would not close on an early cabin version (sail number in low 500s).
The moral is, if you have a recently made cabin boat with leaking
lockers, and are unsure about the thickness of strip required,
consider the bead of silicone sealant solution, or speak with Peter
Reid to see if he can identify when this changed.
The procedure/
method:
1) Remove all
traces of the existing strip. Use scrapers as necessary.
2) A yellow glue
residue is left on the lid and you will need to remove this
completely for the new strip to hold. A stainless steel “brillo
type” scouring pad (not a green plastic one or the steel wool one
with soap) is useful to scour away the residue and prep the
surface of the gel coat. You see these scouring pads in hardware
shops and the supermarket.
3) When you see
clean white glass fibre all around the underside of the lid, degrease
thoroughly using Methylated Spirit. (Editor note: While meths is a
good cleaner, I prefer to use acetone when degreasing).
4) Stick on the
strip nearest to the hinge first. Check the measurement for the strip
to go across the full width of the locker, nominally 1.00 metre. Take
care not to cut it short, as it will compress.
5) Remove backing
paper progressively as you work along the strip.
6) Then do the
sides. Check the measurement, nominally 0.36 metres, from the edge of
the strip you have just stuck in, to the front locker lip. Again,
take care not to cut it short, as it will compress.
7) Finally do the
front edge. Check the measurement for the strip to fit snugly in
between the two side strips, nominally 0.92 metres. Yet again, take
care not to cut it short as it will compress, and if anything, cut
this one generously so you don’t leave a gap.
8) Now close the
locker. Until the seals bed in, the locker will be VERY tight to
close, so much so, that you will see a bow in the locker lid.
Eventually the seal will retain a distinct impression where it makes
contact with the mating locker upstand, and the bow in the lid will
diminish.
If you find the
self-adhesive layer has come off the strip, or the strip has detached
from the locker lid, it is unlikely to stick back. Rather than using
another new piece of strip I have had success picking the self
adhesive off the strip (it is a very time consuming job if you are to
avoid damaging the surface of the strip), degreasing everything with
acetone, then using Evo-Stik Trade TX528, a more industrial
thixotropic version of normal Evo-stik impact adhesive.
Editor note: I
replaced the starboard seal on my Hawk using this method. It took a
long time and a lot of elbow grease to get the yellow glue residue
off the lid. Knowing what I now know,
I suggest the first method you chose is the bead of silicone sealant,
as it costs less and is pretty fast, and only replace the sealing
strip when the original is showing signs of fatigue.
The
tap washer trick as told to me by Rom Meager.
Rom said he got
this tip some years ago from a boat based at Windermere. It’s a
simple and quick way to increase the downward pressure of the locker
lid against the upstand, so the existing sealing strip forms a
tighter seal.
Method: Undo the
locker lid bolts on the hinge and put a tap washer between the hinge
bracket and the top of the locker lid (so the lid is 1/8th inch
further away from the metal hinge). Use a tap washer for each bolt if
you have got space (or enough tap washers).
How well does it
work? Rom has now used it on two boats, and while both have taken in
some water in heavy seas, he reports it is much less than it used to
be.
Editor note:
Simple and quick. This method will improve the seal at the hinge
line, but obviously the sealing strip does not get extra compression
at the front of the locker where the catches are. So you should still
plan on some water coming in.
