Getting to the bottom of it, or, "You're all wet" and hatching the light
We grit our teeth and cut out the aft sliding companionway cover (like a
solid hatch), VERY carefully early this week. Sanding and epoxying the tops
and edges where the nasty teak used to be, the next day we were even more
nervous as we prepared to bed the custom-cut piece of plexiglass with the
same stuff they use to apply windows to skyscrapers...
Ours is a sliding hatch which is a companionway for the convenience of not
having to disturb the pax in the "third stateroom" walkthrough, used mostly
as a last resort for cruisers trying to stuff as many folks as possible into
a charter. Most of our models (M46x) have removed those in the course of
modification, though the occasional original equipment can be found.
The hatch was laid up fiberglass reinforced with 1/2" marine ply. We left
1.5" as support for our nominally 24x30" area but we left about a quarter
inch all around for expansion and contraction - minimum is an eighth - so we
have about a 1.25" lip which will be supporting the glass.
Minimum depth of adhesive is 1/16" and recommended is 1/8, so I got a bunch
of 1/8" tile spacers and positioned them around the area which will receive
the goop. Calculated volume of the tube showed that I should have ample to
do my job, including the about-1/2" slope to the hatch from the edge of the
plexiglass, with the calculated volume of the tube being fully 25% more than
the calculated volume of the joint.
We had to relieve the doghouse under which the hatch slides due to the added
height of the goop and the glass; it was a lot easier with the hatch cut
out, but in the areas where there was still a lip (which, recall, was
supporting the glass), and, worse, across the top of the frame of the
slider, we had to use a file, wrapped in sandpaper, to get to that.
Before we started with the goop, we let the sun get a little less direct so
as not to cook the glass or the goop. All the taping on the glass (cut out
the protective paper for the adhesion area, taped to the edge of the paper,
plus all the top, which still has the protective paper on it), the hatch,
and the cutout area below, were finished mid-day. A wipedown with acetone
just prior to application will assure the cleanest and driest possible
surface for the goop on the hatch; the glass itself will get no acetone, as
it's a solvent to the material!
The hatch went in relatively painlessly, but either my math fails me, or
there's something else at work, as we had next to no leftovers to make the
fillet from the top of the glass to the hatch cover. We have a tiny bit out
from the edge of the glass, but not much! Yet, that would probably suffice,
other than the gutter we have in the expansion zone left between the hatch
edge of the inset and the glass. On the other hand, the underside joint is
a piece of artwork, if I do say so myself, and it looks so good that Lydia's
considering not painting the edge of the wood, after all, as the dark 1/8"
above it, which is a straight up, rather than fillet, line works well with
the different layers of plywood, visually.
Unfortunately, we'd masked the top of the hatch to the level we expected, so
there's a bit of a mess, along with the undesirable place for water to
puddle. Another tube of this special stuff was quickly on the way. By the
end of the week, it had arrived, as had the moment of truth. However...
We went back to aft berth, We had a moment of panic in the aft cabin this
morning, as there was water on the berth base (the cushions are out, at the
upholstery guy's). Drops coming from all 4 corners of the new hatch light
installation!?!?! with the rain falling outside...
Feeling around the joint of the new glass, there was no moisture. It finally
dawned on us that we'd removed some screw-in snaps for a cover, but hadn't
filled the holes, expecting we'd be finished before now (waiting for some
more of the special bedding compound to arrive, as we were slightly short),
and would properly caulk immediately after taking up the painters tape which
now covers those holes.
The mastic for the aft hatch project arrived by the end of the week.
Included in the package was a pair of gloves and a rubber sqeegee. The
rain had stopped by that time, so in preparation for the final step, I went
to get the little bit of rainwater present in the gully out , using a paper
towel to wipe, and found that it was still very tacky. It should make a
great bond with the new stuff.
Way cautiously, I cut the tip of the tube to match up with the distance on
the angle of missing goop, including the flat nipped off to allow the tip to
ride easily along the tape line. Then, millimeter by millimeter, I moved
slowly along, adjusting the rake of the caulk gun to accommodate the
different distances to cover.
Only a few hiccups along the way, and it was time to bevel it with the
special rubber tool that had been included in my shipping box. That, too,
was by the millimeter, but eventually ended. Amazingly (at least to me), it
took a half tube to accommodate that addition.
Up came the tape: Beautiful!
Fill the screw holes with plugs, and we head back to the barn.
At the moment, the glass is ringed with dive weights, to keep it hard on the
spacers and stable. Full cure on this material is 3 weeks, so it will
remain in place for that time, just for safety's sake, as we don't expect to
be back in the aft cabin before then. (The aft cabin is our normal sleeping
place, but we've moved to the forward cabin during all the work which has
taken place in there and while the bed cushions are off at the
reupholsterers, allowing us to use that area as a place to put tools and
other stuff we're using all the time, without it being in our way.) We took
the scrap piece of sunbrella, salvaged back when we were still in our
initial refit 4+ years ago, which I'd used to shelter our portable Honda
generator, to shade the finished assembly so as not to have the paper
coating still on the top level, or the tape, which we applied immediately in
order to have that in place when the new tube arrived, cook in the direct
sunlight. Musta worked, as it came off just fine. Lydia literally gushed
over the end result, and, if I do say so myself, it's a nice job :**))
Eventually we'll have pix of this process, but right now we're all winkies
(euphemism for excretory exits) and elbows, so we've not done the first bit
of editing, or, actually, even LOOKING AT the pix we've been taking.
The next really fiddly project was the forward head leak remediation, trim
varnishing and caulking. While we waited for the new bedding stuff, we
prepped the forward head for new caulking around all the newly varnished
teak. How many people would tape each piece of teak trim, AND the areas
surrounding them, before bedding the teak and making caulk fillets around
both sides of each piece? That would be Lydia :**)) I just get to fill in the
blanks, so to speak...
So, as usual, time passed, and several false starts were made on getting
going, chiefly due to waiting until it was cooler, but not so cool as to be
dark. A couple of days' attempts were frustrated by one delay or another,
but we finally got started on it, this time, in the morning.
Wouldn'cha know it, we ran out of caulk (well, sealant, really; caulk is for
a different type water problem on a boat), thinking we had another tube of
it. It was something else, by the same manufacturer, and no more was to be
found, anywhere. With some trepidation, I switched materials after a
frantic search proved fruitless, and, this time, truly in the dark, working
by the light of a drop light, completed the job well after cruisers'
midnight (commonly accepted as 8PM in the cruising community). Fortunately,
and, I'm chuffed to say, it turned out great, including one spot we expected
to be really a challenge to make look good AND work.
Meanwhile, our tireless grinder continues removing old bottom material in
preparation for application of a new barrier coat and bottom paint. A
barrier coat helps assure that no moisture reaches the relatively
hydroscopic (absorbs water) fiberglass from which our hull is made.
Much is made of blisters on a fiberglass hull, and, while they're usually
not of any structural concern, they're unsightly when the hull is out of the
water, not "fair" (the bottom isn't smooth) and otherwise something that
most cruisers want to "fix."
To do that, most who remove all the covering material down to the raw
fiberglass try to "dry the boat out" by leaving it open for a time
(sometimes, years). However, it turns out that it's not WATER that comes
out of a blister, or hides, deep in the lamination. Instead, it's water
soluble compounds used in the resin formula when it's made.
Thus, one could wait forever and not get any dry results from testing with a
moisture meter. Counter-intuitively, the cure for a "wet" layup (the
fiberglass laminate) or blisters is to saturate them with water, which will
allow the hydroscopic material to migrate to the surface as the water dries.
One then pressure washes it off the hull, and keeps doing this until the
moisture levels reach a satisfactory level.
Thus, we'll be pressure washing the boat after keeping it wet for a minimum
of 30 minutes and allowing it to surface-dry, as many times as we have time
to do before applying our barrier coat and bottom paint (the latter being
the stuff which discourages marine flora and fauna from attaching itself to
Fortunately, we discovered only a few, very small, blisters, which were very
easy to grind out and fair. The occasional actual repair will be easy to
do, too, which makes us very hopeful that our home's hull will be better
than new (nearly all older fiberglass boats used the same kind of resin as
we, with those pesky hydroscopic materials; ours was barrier coated many
years ago, and our 3-year refit before our launch 4 years ago included
fixing more than 800 blisters, all below the old barrier coat), or,
certainly, better than when we bought it.
The barrier coat applied over the prior peel job hadn't done the
wash/rinse/dry, I'm confident, and most of the blisters we cured were under
it. Further, from taking it off, I'm also confident that the level of
buildup of the prior was nowhere near the level of the gelcoat which was
removed before application, easily seen under through-hulls. Once we've
done the rinse, repeat a couple of times a week until we're satisfied with
the results, We'll apply a new barrier coat - to, in our case, to a
thickness of 20 mils at a minimum, or as much as 30, despite the
"conventional wisdom" that 14-20 is sufficient. The paint comes in two
parts, and we'll use any more than we have on hand, mixing our small batches
until it's gone, once we get comfortably past our 20 mil floor.
Aside from the delamination (restored after salvage) in the turn of the
starboard bilge, the hull was and is (the repair is fine) in great shape.
I'll have pix of the bottom, eventually, in a public site; for now, we
aren't even looking at the pix of the work we've been taking due to wanting
to get out of the yard as quickly as possible. However, there are tiny
pinhole spots showing, and, as I said, there are some metered spots/areas
with a relatively high level. The tiny stuff visible that I've worked on so
far have been very easy to bottom out, but some of them are weeping after
the inital scrubbing (I'm using a round stone in a drill, they're so small).
It will be interesting to see how this wash/rinse affects those areas. I'll
not finish that step until we've done the wash/rinse bits, as they may cure
out themselves, leaving only a tiny surface - dry - blister to remove and
Well, time keeps marching on, as does my blathering. Since we're nearly
packed for our trip to a wedding and a family reunion, and all that remains
for this installment of the boatyard blues (and blacks and reds, in
successive layers) is for us to put up all the tools gotten out which we're
now finished with, I'll leave you here.
Until next time, Stay Tuned!
Morgan 461 #2
SV Flying Pig KI4MPC
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"Believe me, my young friend, there is *nothing*-absolutely nothing-half so
much worth doing as simply messing, messing-about-in-boats; messing about in
boats-or *with* boats.
In or out of 'em, it doesn't matter. Nothing seems really to matter, that's
the charm of it.
Whether you get away, or whether you don't; whether you arrive at your
destination or whether you reach somewhere else, or whether you never get
anywhere at all, you're always busy, and you never do anything in
particular; and when you've done it there's always something else to do, and
you can do it if you like, but you'd much better not."