Mast Step/ Core

[Brendan Watson]

Is the core directly under the mast step, and over the compression post,
reinforced in any way? Or is there simply balsa under there? My Commander
shows mild signs of compression in this area as evidenced by the inner-glass,
around the C-post's wedge. First explorations reveal dark and dry, flakey balsa.
Rather than take out the wedge and post I'm thinking of going the injection route.
After all, the mast could only compress 3/8" and couldn't work much with the rig
down- tight, hard agaist the post and probably not at all if the remaining voids were
epoxy-filled. As long as the exterior glass does not start cracking or crazeing I'm hoping
to avoid more invasive surgery and forestall a gut-job for a few more years.
Does anyone else have this situation going on?

[commanderpete]

What is it about the interior glass that suggests a compression problem? Got any pictures?

Maybe you could get somebody to jump around on deck while you checked underneath for unusual sound or movement.

Might also want to check the base of the compression post down in the bilge.

[ebb]

Don't know that continuing to haul the mast down into the boat is a quick fix. The deck lamination, balsa core & inner lam is an incredibly strong, stiff and almost incompressible composit, even with the point load of the stick on its pad against the opposing post inside.

Any depression or flattening of the designed curve of the deck you can see inside has got to be a fault in the compression post support.

338 had a depression that turned out not to be rot, but just settling, old age shrinking and constant rigging pressure.

Any fix has to take place without the mast up and with the deck in its natural arch. Then like the V.C. sez: get the post fitted exactly bottom and top - with the deck up in its relaxed state.

After tapping the suspected area on the deck for hollow sounds (assuming that you don't have a trampoline effect by jumpin on it,) and finding what the probable cause for the problem is (thru holes for electrics and/or fittings) - here is a idea for a temporary fix:

Chart the suspected area with a pencil. Start drilling 5/16" holes thru the top deck only into the balsa. Stop drilling where you bring up pink wood. Space the holes maybe 1 1/2" apart. Inject low viscosity epoxy into the holes until they top out. I've found 2 ounce syringes at my local plastics emporium that work well. The idea is to create little I supports in place of the rotted stuff. Low vis epoxy will soak into and replace the rotted stuff. There may be moisture inside but if you are lucky you'll get enuf epoxy in for new support and the moisture will eventually disapate Comments anyone?

If consensus sez go for it - the deck lamination is about 5/32" on top of the 3/8" balsa and less than 1/16" on the inside (338), so watch the drill pressure, or you'll go right on thru and will have to tape alot.

[Brendan Watson]

What was visible was a depression around the compression post pad in
the inner skin as if the pressure from above is pressing down and bottoming out on
the post , crushing the core. As I was able to find dark, flakey, but dry, core material in some
exploratory holes I think what has happened is that prior to my owning the boat the core
in this area may have gotten wet. When I sealed everything up the core dry rotted. The same thing
happened in an area of the foredeck. The previous owner pulled out the pulpit and made no attempt
to seal up the areas. When I got the boat I sealed them up right away. Five years later
explorations reveal these ares to have,in some places, no core at all, just big voids with
black dust in them. I believe this to be dry rot caused by succesfully sealing wet material.
This leads me to believe that anytime the core is exposed to water, long enough to soak
in, that extensive work is around the corner. It also leads me to believe that when re-
coring with Baltec that epoxying between the squares, while not required, could slow down
the migration of water through the core area. I saw evidence of this where new rot surrounded
but did not violate an old repair whose boundary was surrounded by solid epoxy.
Cheers, B.
Commander# 215

[ebb]

What do you think might happen if you drill a few holes from inside up into the suspect areas?

[commanderpete]

I don't see any downside to doing a "drill and fill" job on that area. Except that if you later want to do a re-core job in the future, you probably wont be able to get the two skins apart.

I would use the slow hardener. If its still cold out, you could also warm up the boat and/or resin to improve flow.

If the balsa core is all flakey and dusty, you might try sticking a wire into the core after injecting the resin to slurry up the dust and help reach any voids.

[ebb]

well then, if it is truly a TEMPORARY repair
(can I have that in writing?)
put in some polyester.

[Brendan Watson]

Copy that about the polyester, but I'm still gonna use some
somewhere.
Cheers, B.
Commander#215

[ebb]

what I meant about drilling up (carefully) from the inside into suspect areas - is to see if water drips out.

[Mike Goodwin]

I have had success with drilling a couple of 1/2" holes and hooking a shop-vac to one and drawing the water out .

[Brendan Watson]

There isn't any water in the core under the mast as evidenced
by the dry flakey material that I've exumed thus far. That it is dark
its safe to say that it was wet at one time and I probably sealed
it up 5 years ago when a new mast step was installed. Also,
I've got 3/16" holes where I suspect water would congregate.
These holes are a good idea as they will allow the water a way out
and the intrusion to reveal itself. 10 holes- foredeck, chainplates,
and around the mast step and some low spots on the side decks
will keep you well informed. The surest way to spot water intrusion and
ongoing rot (wet), is look for signs of brown liquid, stains or drips. This
stuff seems to dry in place and can be wiped off with water. This is your former
resin reverting to its liquid state. A brown
ooze that collected around on of these weep-holes tipped me off to my
current,ongoing re-core of the starboard chain plate area.

I think this area of the Commander is perhaps its weakest link. There is
no evidence of an effort to seal up the core where the chainplate passes
thru. Instead, you rely on the seal of the chainplate cover whose screws
bed directly into the outer glass and core. Bad plan. This is just the kind
of area that water finds and through its persistence defeats. Before I go
back in I am going to epoxy in the chainpates (waxed) and throughbolt the covers
on through solid,re-inforced epoxy. I think an inch of epoxy all around each chain plate
area is my goal. The only thing to fear is dry-rot.... and taxes.
Cheers, B.
Commander#215

[ebb]

You have an interesting solution there with yer chain plates. It probably should have a new thread, so that replys can be found later.

Interesting that you would mount waxed plates with epoxy thru the deck with the beauty plates over bedded in rubber.

Why the wax? I would think that any working of the plates in the deck would compromise any seal that epoxy would give waxed or not.
The primary seal woukd only be from the covers and what rubber you chose for bedding.

Removal of the balsa in way of the thru deck slots and fastenings is what I'm doing also, but considering an enlarged slot and using 5200 around the plate thru the deck - also the beauty plates. Don't know that they need bolts, but maybe you are right there. More holes.

Seems to me that making a rubber gasket that tenaciously sticks to plate, epoxy and deck is the way to go. Gives more.

I 'cheated' by holesawing the top of the deck in way of the slots, spinning a nail around the circumference, laying in a cabosil/epoxy gel, with some chopped glass, glueing the reduced disk back on top. Later, of course, I plan to paint the whole deck, and apply some sort of new non-skid to make the blemishes disappear. I made sure the inner skin was not cut.

Looking at the circles there waiting for the plates to be cut in, I can't see what's wrong with circular beauty plates. Beveled edges and a lot more rubber surface against sweeping water going down the deck! Don't even have to be bronze, do they? oh well, just dreaming.

[Brendan Watson]

I'm going to glass them in. With a 2 1/2" holesaw from the
outside, I'm gonna cut out the outer skin and the core in a
circle encompassing the chainplate cover screw holes. These I'll change to
to machine screws through solid glass. I'll bring the level of the
fill up to the surface fair, and then grind a recess under the
cover that will be receptive to 5200 and hidden, for the most part from
UV degradation. Even in their current form the chainplates don't move or
work. Fully glassed in the core will be protected and if the 5200 failed
the worst that would happen is that you'd discover a little water running down
the chainplate but unable to seep into the core. Eliminating the cover screws
that die in the core, through bolting them in solid glass, will get rid of 12 of the
most destructive holes in the boat. Also key in this area is to make sure the chainplate
bulkheads are not getting wet from above. If a water path is created the glass-wrapped
bulkheads basically fill up with water and the plywood plywood rots unseen. This happened to
to my backstay bulkhead. A slice down either side and the thing came off with my hand.
note: If you leave 1"of the sides, the fillet, when you scrape out the mushy plywood,
you can fit your new wood bulkhead, protected on top, in the old slot. Some of the tabbing
and fine glasswork requires inspection. These bulkheads are the heart of the rig. I recomend
sealing the core around the chainplates in addition to the 5200.
Cheers B.
Commander #215

[ebb]

[Brendan Watson]

My original question has been answered. There is no reinforcement under the mast step in the core
area. The compression I noticed was not simply from old age and settling. The reason for
this settling is rot. I know because I cut out a roughly 14" square area around the step
area from the inside. Alot of black rot and some wet core mostly towards the fore-hatch.
crushed black dust immediatly under. This abruptly fans out to nice dry stiff, not seen for
forty years, core. I'm going to replace the inside wedge and core with solid glass and treat this area like the chainplates
but on a herculean scale. Strong, solid, water tight, with well protected core,should the inevitable
happen in say 40 years.
Cheers, B.
Commander#215