Deck Hardware; Cleats, chocks, rollers, etc.

[Captain Smollett]

I was on the boat yesterday, in the rain, and noticed the cockpit lockers are leaking like sieves into the bilge.  Most of the leakage seems to be coming from the stanchion bases, which I knew before but this was the first time I witnessed the leaks.

One of the bases was so bad the whole stanchion wabbled - you could practically pull it completely off the deck.  I made giving that one a temporary fix a higher priority than the others.

The plywood backing plate for this stanchion base was a couple of feet square and was really trashed.  The base itself mounts close to one edge of the square, of course, due to the deck-edge.

And yes, Craig, I scraped off all the old silicone that was doing such a fine job of sealing the deck.   ;D

Anyway, for a temporary fix, I used a scrap piece of ply that was on the boat.  It was only a few inches by a few more inches (say about 2-3 times the area of the stanchion base itself).  I put her down with 4200 quick-set.

My question is just how large do those backing plates really need to be?

On the one hand, I realize "the larger the better" but on the other, it is close to the deck-edge so cannot be very large in that direction.  Does a plywood backing plate really need to be about two feet square?  It's my understanding that the purpose of the plate is to spread the load from the screws over a larger area.  It seems to me that such a large backing plate is sort of a waste - that once the plate is slightly larger than the deck hardware itself, you are not gaining much.

Also, I was thinking about replacing them with aluminum backing plates (just a thought at this point, not a decision).  Anyone have any pros-cons of al vs wood backing plates?

How about stainless steel fender washers, say about 3 inches in diameter (possibly cut flat for clearance)? Pros/cons?  Or, should I use a wooden block backing plate AND fender washers on that (this seems the best to me)?

[CapnK]

John -

McmasterCarr among others sell solid slabs of laid-up FRP, which would seem to be a better material than plywood, almost as good as metal (compression-wise), and perhaps even better than metal since it could be bonded to the underdeck, for sealing and strength reasons. Bond it to the underdeck when you are oversizing your fastener holes (and replacing core around them with epoxy.) and you can do both in one step.

Drawback - it is relatively expensive from the above source. That said - you could easily make your own, using polyester resin from WalMart. We used to lay up large slabs to make surfboard fins, thusly:

Get a piece of regular glass, place it on a board for support. Precut fiberglass cloth to a dimension maybe .5" smaller than your glass plate. Mix resin (kick it slow, this'll get thick and heat up), laminate the glass cloth right onto the glass plate 2-3 layers at a time, use a roller to wet things out. Once the layup cures, it'll lift right off of the glass plate, and you can cut custom backing plates from the slab.

Me - I use 2-3 staggered washers, smaller size toward the nut. I think the backing plate needs to be 2-3" or maybe a bit more larger than the hardware base it is reinforcing, but that is just an eyeball measurement.

[AdriftAtSea]

The plywood backing plate for this stanchion base was a couple of feet square and was really trashed.  The base itself mounts close to one edge of the square, of course, due to the deck-edge.

I don't think the additional area was really helping.  The only way I could see such a large backing plate being useful is if the hardware were substantially tied to it... which just mere through-bolting isn't really going to do. If the stanchion was substantially connected to the backing plate, it would give it a lot more strength against torsion...but just through bolting doesn't give a strong enough connection for the additional size to be of any real use that I can see. Also, the backing plate itself would have to be connected to the deck to resist inward torsion on the stanchion... since it doesn't extend much past the stanchion base itself.

My question is just how large do those backing plates really need to be?

On the one hand, I realize "the larger the better" but on the other, it is close to the deck-edge so cannot be very large in that direction.  Does a plywood backing plate really need to be about two feet square?  It's my understanding that the purpose of the plate is to spread the load from the screws over a larger area.  It seems to me that such a large backing plate is sort of a waste - that once the plate is slightly larger than the deck hardware itself, you are not gaining much.

I think that anything about two-to-three times the area of the deck hardware is really going to be the practical limit in terms of gaining support for the hardware.  One thing that a larger backing plate can allow you to do, especially with plywood or fiberglass backing plates, is to taper the edges to gradually lessen the stress, rather than having a hard-stress zone at the edge of the plate. 

One person I know makes up fiberglass/epoxy backing plates using a stainless steel mixing bowl as the mold.. and uses the curvature of the bowl to effectively taper the edges of the backing plate.  This is more time consuming than making them out of plywood IMHO.  I also think that epoxy/fiberglass is better than polyester/fiberglass since the epoxy is the stronger of the two resins.

Also, I was thinking about replacing them with aluminum backing plates (just a thought at this point, not a decision).  Anyone have any pros-cons of al vs wood backing plates?

There are two issues with aluminum backing plates that I see. 

The first is corrosion.  If you use stainless steel or bronze fasteners, the aluminum will have galvanic corrosion issues if any water gets into the fastener holes and such.  You'd probably want to use some sort of galvanic isolator, like plastic sheets and tefgel/lanocote between the fasteners and the plate itself.  Needless to say that plywood backing plates have to be epoxy coated after having all the holes drilled, to protect it from moisture intrusion and rot.

The second is expansion.  Most backing plates are big enough for this to be a problem, but if you were making a single backing plate for a mainsheet traveler or genoa track, it might be an issue, especially if the deck is painted a dark color.

How about stainless steel fender washers, say about 3 inches in diameter (possibly cut flat for clearance)? Pros/cons?  Or, should I use a wooden block backing plate AND fender washers on that (this seems the best to me)?

I wouldn't use fender washers by themselves... especially on a cored deck...since I've seen way too many cases of the washers bending under high loads and compressing the deck underneath them.  Most fender washers aren't thick enough to spread out the strain of a highly loaded piece of hardware by themselves. I generally back all hardware I install with a 1/2" marine plywood backer block and use fender washers under the nuts to prevent really high loads from pulling the nuts into the plywood and loosening the bolts by doing so.   Recently, I started using composite deck lumber for backing boards... I believe this will be about as resistant to compression as the plywood but lower maintenance.  I do use fender washers with this stuff as well.

[CapnK]

I also think that epoxy/fiberglass is better than polyester/fiberglass since the epoxy is the stronger of the two resins.

Just a quick 'techanical' note for future reference: The reason why epoxy is highly touted as the 'better' resin for boat repairs is that it has a stronger secondary bond than polyester (or vinylester, tho' by a smaller factor than the poly- ), making repairs/additions 'stick' better to older FRP. It is not necessarily the "best" resin to use in every scenario.

By that, I mean that in a strictly compressive use like this one for a simple backing plate, polyester resin should serve just as well as either epoxy or vinylester resins, be considerably cheaper, and likely easier to use, than either of the others when laying up the slab.

John, as an addendum - if you can get some styrene, you can use *just a little bit* to thin the polyester resin, making it easier to wet out multiple layers of cloth. Acetone can also be used in the same way, and you'll probably have some of that around for cleanup. Styrene is preferred because it won't evaporate as quickly. Either way - Just don't get too generous with the amount you add, it won't take much to make a difference. :)

[AdriftAtSea]

Capn K-

My understanding was that the resin itself had a higher tensile strength in a composite than did the polyester or vinylester resins.  Not that tensile strength is all the huge a deal in a purely compressive load situation like a backing plate.

[s/v Faith]

Couple thoughts;

On the one hand, I realize "the larger the better" but on the other, it is close to the deck-edge so cannot be very large in that direction. 

 
  I agree 2 -3 x the area of the item being backed is probably right.  I like to bed my backing plates, in areas where they are mating to something less then flat the 'bedding' distributes the forces better.  For instance, on the backing plate for my bow roller, there was a large area with one rounded off side that tapered to the deck edge.  I built up polyester filler to make a flat shelf to mount the plate to.  If I had not all of the compressive force would have been applied along a 'ridge' of the radius of the bend.

Also, I was thinking about replacing them with aluminum backing plates (just a thought at this point, not a decision).  Anyone have any pros-cons of al vs wood backing plates?

  Aluminum is used by many boat builders, and should be fine.  My stern cleats have Aluminum (3/8" much thicker then needed) plates, but still have epoxy coated plywood plates under them...  Why? you might ask.  My thinking is that the wood has some give (not much) to resist shock loads from pulling the cleats from the deck.

How about stainless steel fender washers, say about 3 inches in diameter (possibly cut flat for clearance)? Pros/cons?  Or, should I use a wooden block backing plate AND fender washers on that (this seems the best to me)?

  Wooden backing plates with fender washers would be strong, and certainly much stronger then what most boats are specked with.

Also, something I have done aboard Faith is to lay up fiberglass and cut mounting pads that I epoxy to the deck where an item mounts.

  This serves two purposes.  First it makes the bedding compound's job easier by raising the seal off of the deck level.  That way water does not stand at the joint and is less likely to leak.

  Secondly, it distributes the downward compressive forces across a larger area of the deck.  Something like the bit I have on the foredeck.  It's footprint is something like 3 /34 x 4 3/4 and with the raised mount the area is more like 4.5" by 5.5".

  The bases of my new stern pulpit are 1" tube with small plates welded to the ends with 3/8" bolts sticking out.

  I laid up some fiberglass and used a 3" hole saw to cut discs out;



These are epoxied to the deck, and here is the finished product;



_{Edit to fix quote tags}

[s/v Faith]

One other thing about stanchion bases, while the plate can more easily extend inward then outboard (because of the toe rail), that is where you want more surface area anywhere.  There it can better resist the person leaning against the life lines (not that force is never pushing them in). 

[Captain Smollett]

These are epoxied to the deck, and here is the finished product;

Very nice work.  I like that idea.

I realize now that I have about 1000 questions (on various maintenance/repair topics).  The first, though, is how thick are you making those pads, in glass layers?  One layer, two?

Also, I was thinking about doing the same thing for the backing plate (a la CapnK's suggestions), but again am wondering about thickness.  Preferably, I'd like to be able to make both top pad and backing plate from the same 'batch' of glass just to keep things simple.  I like simple.  :)  (But I also want "right" and "strong")

As a follow-up question, I found some delamination of the deck glass from the core yesterday under one of those leaking stanchions.   >:(  There probably would have been less of a problem if someone at some time had used real sealant instead of silicone, but I digress.

Anyway, I'm pondering the best method to fix this.  The top layer of glass is cracked and very brittle, so I was thinking about replacing the whole section - say about one ft square.  I was thinking about chopping out the core material, filling the whole enchilada with thickened epoxy (or polyester better?), then covering with a layer of glass.

Or, as an alternative, I was thinking about treating this as a hole in the hull I wanted to fill, and doing up multiple layers of glass to build it up.  I'd grind the hole to about 12:1, as in filling a thru hull.

Which of those two plans is better for a largish deck repair?

I have a suspicion this won't be the first such repair on stanchion bases.  It would have been nice if a PO had fixed the leaks, instead of performing a placebo repair that only LOOKED like it was sealed.

An last but not least, for now, a PO epoxied the coaming board into place and I now need to remove it.  I'm thinking heat gun and a chisel.  I really don't want to destroy the board, or the deck for that matter, so I guess the key word here will be "go slow."  Any thoughts?

Thanks.  Questions 4-1000 to follow at a later date.   ;D

[Bill NH]

An last but not least, for now, a PO epoxied the coaming board into place and I now need to remove it.  I'm thinking heat gun and a chisel.  I really don't want to destroy the board, or the deck for that matter, so I guess the key word here will be "go slow."  Any thoughts?

Go easy with the chisel...  you don't want to damage or remove pieces of the deck that are well bonded to the coaming.  The board can be replaced, the deck is a bit more difficult   ;)  If you choose to sacrifice the board, a small grinder with a 50ish grit abraisive disk is a good tool for fiberglass & epoxy "modification" work.  Cut the board back, and then you can remove the remaining material with the grinder in a controlled manner, rather than having it separate at the weakest point... 

[AdriftAtSea]

Capn Smolllett-

For the delaminated area, I would replace the core with more core...rather than going solid epoxy or solid laminate.  Both will be much heavier than the surrounding or original cored section would be.  Obviously, for directly under the stanchion itself, I would go with solid laminate, as I think it will be stronger than thickened epoxy. 

Regards and good luck with the coaming.. the board is far more expendable than the surrounding deck. ;)

[s/v Faith]

These are epoxied to the deck, and here is the finished product;

Very nice work.  I like that idea.

I realize now that I have about 1000 questions (on various maintenance/repair topics).  The first, though, is how thick are you making those pads, in glass layers?  One layer, two?

  The pads you see in the picture are about 1/16, there are 2 discks stacked for about 1/8".  I wouldnot recommend trying to make the backing plates out of the same material.  I would go much thicker with the backing plates under the deck (your epoxy coated plywood, with fernder washers sounds good).

As a follow-up question, I found some delamination of the deck glass from the core yesterday under one of those leaking stanchions.   >:(  There probably would have been less of a problem if someone at some time had used real sealant instead of silicone, but I digress.

Anyway, I'm pondering the best method to fix this.  The top layer of glass is cracked and very brittle, so I was thinking about replacing the whole section - say about one ft square.  I was thinking about chopping out the core material, filling the whole enchilada with thickened epoxy (or polyester better?), then covering with a layer of glass.

This is a good plan.  replacing core in such a small area is pretty pointless.

Or, as an alternative, I was thinking about treating this as a hole in the hull I wanted to fill, and doing up multiple layers of glass to build it up.  I'd grind the hole to about 12:1, as in filling a thru hull.

Probably not necessary, but would be acceptable also.

[s/v Faith]

Capn Smolllett-

For the delaminated area, I would replace the core with more core...rather than going solid epoxy or solid laminate.  Both will be much heavier than the surrounding or original cored section would be. 

  I have read this online also.  I believe it is absolutely bogus.

  If you removed the entire core from the deck and replaced it fiberglass you might add 75# total to the weight of the boat (probably more like #50).  The Alberg 30 barely knows when a 200# man is on the rail.

  I removed my #25 anchor and #60 of chain from the anchor locker on my Ariel today.  Much to my surprise I noticed no change in how she was riding on her lines.... But then again what is 85# to a nearly 4 ton boat?

  The foot or so of core replaced with much stronger (and more expensive) fiberglass or a sandwich of thickened epoxy will add a couple pounds to the boat.....

[Sandy]

Alright heres another " got any ideas" question.
My CD27 didn't come with any type of anchor storage on the bow.  I hang my Danforth from the pulpit,which works great. Problem is I cant store any other type of anchor up there. I would like to store a Delta there as well.

So any of you folk solve a similar problem? Any ideas?  I'm not looking so much for a roller to launch and retrieve as much as a place to securely stow the anchor.   Thanks

-Sandy

[Captain Smollett]

Store-bought rollers are one solution, but I am chosing to go with a home-built roller.  I am shamelessly stealing my 'design' from CharlieJ, so hopefully he will post a pic here of his roller to see what he did.   ;D

[Tim]

Sandy, What I did, because I also have a Danforth on the pulpit, is put a pulpit anchor to one side with a carabiner holding on the Delta. I then bungee the shackle end to the pulpit. It has worked fine for the last two years, as easy to deploy as the Danforth.

[AdriftAtSea]

I went with a store-bought pivoting bow roller.  It just made a lot more sense, especially with the primary anchor I've got to do that.  The Rocna 15kg doesn't really store well anywhere on a boat but on a bow roller of some sort. :)

Here's a photo of the ground tackle setup I put in last spring.

[CharlieJ]

ask and ye shall receive ( sometimes) ;D

All done with 5/4 mahogany. The roller runs on a 5/8 stainless shaft. Had to move the pulpit aft to where it is. Also had to cut toe rail and move bow chocks aft, since none of this existed when we started.

Boat originally had a single 6 inch cleat forward. Now has a pair of 10 inch Bronze Herreshoff style. I HATE undersized cleats and most on todays boats definitely are undersized. If you can't easily get two anchor lines onto the cleat, it's too small.

Anchor is a 22 pound Claw, with 75 feet of 1/4 inch G4 chain and 200 feet of 1/2 nylon

[Sandy]

Man you guys are fast!!(and apparently I'm a bit slow)
By the time I typed my reply I had TWO new replies...WITH PICTURES!!  Grog all around!!

The picture I had in my head was kinda a cross between Charley's & Adrifts.  I thought of building a platform and pointing it out at an angle. My anchor chocks are part of my stem plate. I like it!!  Thanks a ton guys.  Always helps to get others ideas. The pictures are great.
Thanks again
-Sandy

[AdriftAtSea]

Charlie-

I'm surprised you don't have a bail on your roller, to prevent the rode from jumping off the roller.

BTW, the primary anchor on my boat is a 15 kg Rocna, with 75' 5/16" G4 chain and 150' 5/8" rope.  The secondary, which is will be kept in the cockpit is a 14 lb. Danforth, with 15' 5/16" G4 chain and 150' 1/2 rope.

[Tim]

I would actually love to put a roller on, but that would necessitate moving my bi-color and keeping my secondary anchor below. As I have rode on both and very little room on my small boat I will probably keep the setup I have.