Mount Pads

[mbd]

There was a thread going around on the Triton List recently about mounting the deck hardware on pads to raise the mount point (and water intrusion point) above the deck level and any standing water on the deck:

I have mounted numerous additions to Head over Heels on mount pads....not the stanchions or pulpits(!), but just about everything else.
I feel that sharp inside corners are places where dirt can accumulate, so I made pads, some as thick as 2 inches for anchor rollers, to raise attachments off the deck. The bases are teak, cut and contoured to match the part I was attaching.
Each base was designed to extend about a half an inch from the base of the piece I was attaching. I route the upper edge for a smooth round over. I would then remove the nonskid a half an inch out from that. The pads were saturated with epoxy and let to cure. I used epoxy with filler to glue the teak in place. When cured, I would use epoxy and sandable filler to run a fillet around the deck/pad joint to create a smooth transition from the horizontal to the vertical. I usually use a West System stir stick for the radius of the fillet, but in larger fillets... Each pad was then painted, white in my case.
The result is a pad which has a smooth, rounded transition from the deck to the top of the pad. The appliance I attached was then centered and through bolted for a clean and hopefully "factory-like" finish.

Here are the pictures Rob Squire sent out. Thanks Rob!

Anyone else done this? As I'm gearing up for my recore, this is something I'm certainly going to consider! Simple and elegant - great idea!

[epiphany]

Personally, instead of painting the blocks, I'd go ahead and glass them in, perhaps with pigment. (...Or maybe not - might use polyester resin (for UV resistance) in a clear glossy finish to show off that teak. ) Seems like painting those blocks would just cause more work down the road, though, when they need repainting in a year or so.

Good idea, though, and good pics of the implementation. I like using the router set shallow to remove the non-skid - very clever. Thx for the post, Mike.

[mbd]

I was thinking once Tony G. perfects his molding techniques and lets us all know how to do it, that making solid blocks would be the way to go. That way there's nothing to rot. Or even building up the area with foam core material and glassing it in and sanding it.

Would that work?

[mbd]

With the arrival of the stern rail and after cutting out some more deck with rotted core underneath where the stanchions had been mounted, I've been thinking about this topic again.

How about a plaster or clay or even playdough mold? The stanchion bases or other hardware could be pressed into the material to make an exact match, let the mold harden (or not), then epoxy with thickener and/or high density filler could be poured into it and let it set. You'd only need the final product to be 3/8" or so. I'd make it thicker initially so it could be sanded to fit the camber of the deck, etc., then epoxied in place once it was fit.

What would/could/should I use as a mold release in this scenario?

[ebb]

Commadore Bill uses fat varnished teak pads on some of Maitai's fittings.
Not sure why you have to have an impression of the stanchion foot in a pad to which it will be mounted? My first caution on this is that saltwater shouldn't have an opportunity to soak the base. Even if you put the rail on with rubber. Water will puddle anywhere. Especially in little cracks.

If we are talking about mounting hardware on composite:
Believe the foredeck should be recored befor mounting hardware, and the stanchion base mounted on rubber gasket with a backing plate inside. But you could holesaw a round hole just thru the TOP skin of the deck into questionable balsa where the pulpit bases mount and dig it out. The holesaw is an easy way to get a decent shape. If you are close to the toerail, it's not all balsa. Then fill the hole in flush with the deck with epoxy/mat. Could even glue back on the piece of deck you made with the saw.

This will get the pulpit mounted and later you can do the bigdeal deck recore. Inside, I would glue on a larger backing plate than the hole you've filled.
There's no balsa core in the aft deck, ofcourse, and putting in backing plates will be a real chore. Might have to hire a little people to get in there.

It is interesting idea to beef up the mounting area of a fitting with an exterior pad, but I believe you still have to have a backup pad inside to spread the load over the skin. The cabin top is a real problem with its floating interior liner.

Disassembling 338 produced a collection of fiberglass squares that Pearson used as backing for track and stanchions, etc. Backing is essential to mount anything anywhere on the decks. Hope I understood yor concern?

[commanderpete]

Maybe you dont want to make a very rigid mounting for the pulpits.

I've bumped my bow pulpit into a piling and seen the deck flex beneath it. Something has to give. Bending and kinking the pulpit would be bad.

If the worst should happen, the bigger the backing plate, the bigger the hole ripped in your deck

I wonder

This is Commander 105 after being attacked by another boat during Hurricane Isabel

http://www.pearsonariel.org/discussi...achmentid=1691

[mbd]

Ouch! Strange, it looks like the fiberglass showing on the ripped deck in the picture has not even been wetted out??

On the mount pads: my goal is to move the "seam" where the hardware is attached to the deck to a level higher than the normal deck level. i.e. If the fitting where at a low spot, the water would pool around the base of the mount pad rather than the seam where the piece of hardware is attached to the deck. (Now I need to hunt around for a picture to show this - I think Cape Dory decks are made with this feature...)

[ebb]

Mike, this is fundamental stuff.
Hope Mike Goodwin comes in on this.

105's damage is extensive. It looks like it was caused by more than a bump or a single attack. It looks like it took some time to cause it - a lot of banging and pulling and pushing.

The old polyester laminate in 338, as an example, is amazing hard and strong. It is possible, like with tabbing as an example, to 'peel' it back with a sharp chisel. This has happenened on 338 a couple times. It is most disconcerting to suddenly get bare fiberglass out of what looks like 'saturated' translucent green. The peeling stops and doesn't seem to continue - it seems to be an example of what happens to frp in SHEAR. Or, what to call it: sideways stress. I think frp can be prone to this, tho I've never run across this in words, nor trained as an engineer.

This maybe is what we're seeing in C'pete's photo. It took a lot of work for Isabel to do that, and it took time, doncherthink? We're looking at huge force being applied to the EDGES of the deck and hull, once the joint was breached by the piling.

I'm for wider backing plates every time. It is in the nature of fiberglass skin construction. I'm for the tube to bend befor a hole is pushed into the deck. A hole from a stanchion being ripped out? THAT is hard to take! I believe I would want the deck, whatever, beefy enough so THAT wouldn't be possible! I would want the tube to break befor it caused a hole thru the deck.

Flatter (rather than taller) and wider backing plates with chamfered edges is the way to go imco. And creating a sandwich with a top plate coupled with the inside one - nothing wrong with that.

But no hard edges, if you do it to 'code'. A hard edge creates a break point, like maybe a crease in a sheet of paper. Kinda gives the deck or hull an idea of where it can break. All transitions smooth and gradual is the theme with fiberglass.

[bill@ariel231]

MBD - "On the mount pads: my goal is to move the "seam" where the hardware is attached to the deck to a level higher than the normal deck level. i.e. ... I think Cape Dory decks are made with this feature...)"


Mike you are correct, I replicated CD's feature on my stern rail install by wrapping the stern rail bases in a release fabric (e.g. saran-wrap) and bedding the stern rail in place (temporarily) in thickend epoxy (a 1/16th to 1/18th inch lift from the deck was all it took). once the epoxy was hard, a little sculpting with a dremel tool was all it tool to finish the pad.

[mbd]

You wouldn't happen to have any pictures of the process and/or finished product, would you?

Maybe it would clarify what I'm evidently not explaining very clearly...

[bill@ariel231]

I can post an "in-progress" picture tonight. I took some close up pictures of the process after the rails were bolted in place but before painting that will make this clearer...

[Al Lorman]

A number of people do believe that raising deck intrusions is a good way to prevent leaks. I've been watching, via the Internet, as a very skilled guy rebuilds a C&C 38. He used premade fiberglass sheet stcok to raise things like his deck fill. Here's the link to his diesel deck fill raiser: http://www.wbryant.com/StellaBoat/Pr...esel/index.htm
He made a similar pad for his steering pedestal.


Al Lorman

[bill@ariel231]

Mike

I bedded my stanchion bases in thickened epoxy to make up for the small mismatch between the deck and the stanchion bases. It also picked the bases up 1/8th of an inch (like the Cape Dory 33 etc.). no leaks 10 years later. Here's the method I used: (1) the stanchion was wrapped in plastic wrap to protect it from the epoxy goo; (2) a thickend epoxy circle was troweled on deck where the stanchion base was to meet the deck; (3) the stanchion was bedded in the epoxy (all 6 legs at once); (4) once the stanchion pad had hardened, the pad was trimed with a dremel fitted with a small sanding drum. Of cource, the final install needs a backing plate below decks. here's is a drawing:

[bill@ariel231]

here's what the stanchion bases looked like before the paint:

[bill@ariel231]

I couldn't resist. while the epoxy was out, I took the liberty of changing the handles on the cockpit lockers...(off topic but you may have a bucket of epoxy mixed up for the bases)...