Brass Plate on Keel

wiltsan · Post by **wiltsan** » Mar 26th, '07, 06:26

What exactly is the brass plate mid way on the starboard side of the CD 30 keel?

Thanks

barfwinkle · Post by **barfwinkle** » Mar 26th, '07, 07:20

Hello Wilstan

If it is external it should be the splinter plate to which all of your rigging is attached to in the deep bilge.

In case the boat is hit by lightening, then then energy is transferred to this plate and it then explodes into thousands of little BBs, hopefully taking the brunt of the strike and saving the rig.

For the life of me, at the moment, I cannot think of the correct name for the plate, but someone will respond that does.

Fair winds, oh and don't paint over it.

Bill

ricks · Post by **ricks** » Mar 26th, '07, 07:28

I think I have seen this referred to as the Dynaplate in the archives?

I have a recently posted thread asking whether anyone has ever had to re-bed this plate and if so, how was it done? Don't mean to hijack your thread but was wondering if anyone has any experience?

Rick

Jerry Hammernik · Post by **Jerry Hammernik** » Mar 26th, '07, 08:33

When I redid all my thru hulls, I also did the grounding plate. It was held in with two bolts. Removed the nuts in the bilge area, pried the plate off, cleaned, (wire brush in a drill to get old bottom paint off) and rebedded. No big problem. As a previous poster said, don't paint.

s-dupuis · Post by **s-dupuis** » Mar 26th, '07, 12:11

I was also curious about a roughly 2" diameter, round plate with an approx. 3/4" hole in the center, located on the keel on the strbd. side. I've never seen this on other boats and wondered what it is. It looks a bit elaborate to be a grounding plate so I'm guessin it is the 'Dynaplate' mentioned above.
I'll take a closer look at it this evening for a better description or even a photo. If it is indeed for lightning protection, I should be able to connect a multimeter to it and one of the shroud bases to see if it makes a circuit.
Thanks for posting the question. I forgot about it among the long list of stuff I'm upgrading and improving.

Steve

Bill Goldsmith · Post by **Bill Goldsmith** » Mar 26th, '07, 12:49

s-dupuis wrote:I was also curious about a roughly 2" diameter, round plate with an approx. 3/4" hole in the center, located on the keel on the strbd. side.

Steve,

What you describe sounds like a Garboard Drain, which is designed to keep the hull from filling with water during layup. Just remove the plug upon layup, and REMEMBER TO PUT THE PLUG BACK IN when launching. Here is a pic:

[img]http://images.westmarine.com/full/garborddp_f.jpg[/img]

A Dynaplate is larger and rectangular, and has no fitting to be opened:
[img]http://images.westmarine.com/full/05872_f.jpg[/img]

s-dupuis · Post by **s-dupuis** » Mar 26th, '07, 14:24

Thanks Bill.

Yes, that is very similar to what is attached to my keel. Funny thing though, there did not appear to be a square plug in mine although I did not look that closely. Something is in there though, or else the boat would have sunk long ago. Fortunately, there is no water in the bilge to drain. I assume you meant " to keep rainwater from filling the hull during layup". That would be a big leak above the topsides and a lot of rain but I can imagine a few scenarios (I have a vivid imagination) that if combined would cause the hull to fill to disasterous proportions (no tarp, clogged cockpit drains, Oswego type snowfall, etc.)

Thanks for solving the mini mystery.

Steve

Bill Goldsmith · Post by **Bill Goldsmith** » Mar 26th, '07, 16:48

s-dupuis wrote:I assume you meant " to keep rainwater from filling the hull during layup"

Yes, I meant rainwater while on the hard. A few storms can accumulate a lot of water if the boat is not well covered and water finds its way in. My old 27 had a garboard drain, but I never touched it--did not need to. My 32 does not have one. Removing the speed impeller actually serves the same purpose.

Sea Hunt · Post by **Sea Hunt** » Mar 26th, '07, 17:02

Yet another dumb question from the boatless guy in Miami.

If the CD 22 (or any other CD) is on the hard, does not opening the two seacocks port and starboard aft of the battery box (I seem to recall that is where they are on a CD 22), allow drainage of any rainwater from the cockpit

marilou · Post by **marilou** » Mar 26th, '07, 17:22

Yes, those drains will drain the cockpit. What "the above" refers to is the "Garboard Drain", which allows you to drain the inside of the hull or keel when you are on "the hard". The "Dnnaplate" is for electrical grounding. I think you have grown pass the tadpole stage, even without your flippers (boat).

wiltsan · Post by **wiltsan** » Mar 26th, '07, 20:49

Thanks for the responses, I thought that it was a splinter plate.

When I hauled the boat this season the plate was heavily corroded. I keep the boat at a slip, should I assume that there are some stray electricity flowing through the marina?

I am assuming that I need to take a steel brush to the plate?

Thanks Again!

Wayne Brown · Post by **Wayne Brown** » Mar 26th, '07, 21:00

At the suggestion of Indian town Marina in Florida I installed a garboard drain in my CD-27 WHISPER this year. Their thought was if the wind and rain from a hurricane or other wet windy storm hit the boat in just the right direction a normally dry boat could accumulate enough water to make the boat unstable on the jack stands. My knot meter transducer is located just high enough in the hull that the cabin sole would get wet before draining the bilge.
Wayne Brown

Oswego John · Post by **Oswego John** » Mar 26th, '07, 21:49

Although several companies manufacture a grounding plate for boat hulls, the Guest Corp. seems to have the vast majority of the market cornered with their version of a plate, which their trade name is called Dynaplate.

The plate comes in four sizes and is made of sintered bronze. It has several functions. It is mostly considered a discharge terminal for grounding for lightning strikes. For a properly grounded vessel, it also serves as a ground for electronic equipment. Because of it's proximity to zinc on the noble metals chart, it provides additional protection from electrolytic corrosion.

Prices quoted for a Dynaplate are all over the checkerboard from one dealer to another. I find that Performance Yacht has some of the lowest prices for grounding shoes. For interesting information and prices, go to:

www.pyacht.net

At the upper right of the home page, at Search, enter Dynaplate, hit Go

I'm having some problems with the regular url.

Yes, you can clean the shoe with a wire brush.

Good luck,
O J

Mike Thompson · Post by **Mike Thompson** » Mar 27th, '07, 20:07

When I was searching for a used boat to buy, I came across two boats
which were full of water above to the cabin sole. In one case the fuel
tank had leaked into this...

In my CD28, I have installed a plug which I remove in the fall. It doesn't have a
square nut (as shown in a posted photo) but a handle several inches long.
I don't visit my boat even once during the winter and this drain gives me
some piece of mind over rainwater entry.

The Cape Dory Board

Brass Plate on Keel

Brass Plate on Keel

Dynaplate?

Rebedding

Coincidence

Re: Coincidence

Garboard Drain

Re: Garboard Drain

You are correct - Sea Hunt

Thanks - Next Question

garboard drain

DYNAPLATE

garboard drain