Originally Posted by clemon
In the continuing saga of "Why West System boats like Searunner
34's should not have deck
penetrations", I'm removing a set of large deck
mounted quick release lever arms and cheek plates that are used to tension the running back stays. These also cause the deck to flex, which eventually causes the fiberglass
to crack nearby, which in New Zealand
, leads to the dreaded wood rot. Has anyone come up with a simple quick release mechanism? I've read that a 4:1 block system will work fine, set up sort of like a vang tension system, on each backstay to chainplate system. This looks fine, but cheaper or other clever ideas are worth looking at.
On the continued dread issue of wood rot, I'm starting to get paranoid about the head
stay attachment, as I'm suspicious that water
may be getting into the bow area. I can't tell if water
seeping into this area can drain out, or whether it will pool and rot out the headstay mounting plate. I really wish the searunner
had an external chain plate
for the headstay. Has anyone come up with a clever way of inspecting this area, aside from cutting in through the deck top?
Clemon, you brought up several issues. I'll try to help.
PREVENTING GLASS PUNCTURES:
This gets back a bit to my post about bolt tensioning... For small items, like pad eyes, just proper bolt tensioning should work, because the pad is "almost" perfectly flat, and quite small. For large hardware's base plates, like stantion or bow/stern rail welded bases, they are less in total conformity to the deck, (wavy), and have much larger bases. (Perhaps your lever's base flange was too)?
In these cases I always make a base plate of something hard, and glue these down to the deck, between the soft ply and hardware's SS base. I used a heavily glassed fairing block on the stantions' bases, and disks of 1/4" Micarta = "Phenolic" sheet, (1/2" larger than their bases), on irregular bottomed, larger things, like bow & stern railing's welded bases. (1/4" thick discs of solid glass work just as well for this).
These disks (or squares) are glued on before drilling and prepping the bolt holes, for the hardware
that's to be caulked down later.
They allow the hardware's base to be really tightened down, (contrary to my previous post about other "smaller" hardware), and if you have serious backing inside, with extra plywood and with metal backing plates
, or at least extra ply and thick fender
washers, (you can stack them), then you will NOT damage the glass job at the base of any of these highly loaded fittings. Otherwise, due to "hard spots" in the rail's non conforming custom made base, you will crush the deck in spots, to get others to merely touch. This is future rot, just waiting to happen!
All openings through the hull
or deck, (for bolts, chainplates, etc), need at least 5 coats of epoxy
on day 1, then sand to a better smoother shape, and to pop air bubble pores on day 2, followed by coating 5 more coats of epoxy. Right before installation
, on day 3, a light sand will make room for the bolt or fitting. Then caulk it up profusely! CUTTING CORNERS HERE IS A HUGE MISTAKE!
Yours is a WEST boat
, right? If your forestay chainplate's slits through the deck got this treatment originally, (100% perfectly as I suggest), then even if the chainplate leaks
through, rot is not the issue... CREVICE CORROSION
IS! Here, it would be better if they were of 316 grade SS, or better yet, TITANIUM!
I have 1/4" wide moats of this 1/4" thick Micarta sheet around each chainplate, and fill the void with a generous fillet of 3-M 4000 UV. (replaced every 3 years) I dig down in the slot about 3/8 to 1/2" with a razor knife, way past the broken down & un-adhered surface (1/8" layer of caulk). That exposes where crevice corrosion
would be, if it hasn't leaked past, and if so, you would see evidence.
I never have needed to, but you could then dig deeper. If it looks bad, replace the whole cp.
Ideally these chainplates would be made with 2X4" or so welded on base plates, just above the slots, and the deck would have glassed on base plate "thick spots" of Micarta or sheet glass. This minimizes leak possibilities, and is done on high end production boats.
The above is harder for us to accomplish accurately, making homemade hardware
, and since welds across a chainplate weaken it, a thicker (= heavier) plate would be called for. Normally these are 1/4" thick chainplates, doubled up at the top to 1/2", for better bearing surface area at the clevis pin hole.
Probably, the best compromise would be to use the current concept
, but with proper sealing of the wood at the slot, and use full 3/8" thick Titanium chainplats. (This avoids sealing around that SS doubler notch at the top, and avoids welds too). Being so light a material, the result would be no heavier, easier to keep sealed, (with the described moats), and totally immune to crevice corrosion.
NEXT best option... Do the same with 316 SS, but DO weld the notch to step down CP thickness on there, but way BELOW deck level. With maintenance
, it will last too. Mine are just 304 SS, and I inspect them as well as service
them on a schedule. The're still perfect!
DECK MOUNTED LEVERS, PADS, ETC:
ANY flexing from an upward pull on the deck, must be reduced to "0". The attached photo
shows how I backed a heavily loaded pad eye, (for my preventer), with another one, but upside down under the deck. Using with a pre-loaded turnbuckle, I spread the load down to a strong part of the ama.
REMOVABLE RUNNERS & STAYSAIL STAY:
For one thing, 4 to 1 tackles are better than nothing, but not really up to pounding to windward in giant waves, under staysail, in a gale. If you can't put > 800 #s of pretension on them, the mast
will still pump dangerously. Also, tackles as strong in WL as the wire (or synthetic, like my runners), cost a small fortune.
Hyfield levers, especially for runners, are huge, heavy, and complicated. They don't allow adjustments under load. I don't like them.
I have a nice (but pricey) Wichard snapshackle/quick adjust turnbuckle on the forestay. (by hand only, no tools) I can have all three supports rigged up, but just snug, then tension them in < 1 minute, (for ALL 3), just before raising the staysail. Photo
attached... You see how I put it away when stored, for protected sailing. At sea, it is always made up for use, just looser.
The runners are similar, but cheaper "Johnson" brand turnbuckles. I have these ready for use, but loose until needed, just like the staysail stay. When storing them, I unshackle the shroud
, bunji the turnbuckle as shown to a stantion, and attach the shroud's synthetic line to small bunji storage
blocks, further forward. With wire runners, bunji will not work for this, as wire weighs more and will flop around too much with bunji.
With a genoa
in use, the runners are better stored at the cabin's sides, to prevent conflicts, and I will eventually move my storage
This making up or storing of BOTH runners, takes from 45 seconds to 1 minute. It was the simplest, least expensive, and quickest deployed (but strong) solution I could come up with.
Of coarse, as we all know from looking around, there are about a dozen other ways as well.
Again... for long time readers, I apologize for repeating myself here.