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I am assuming that these items are Zincs but not sure. They look used up and probably be replaced, but are they grounding plates??

Joseph,

Looks to be a zinc to me. Is it tied into your bonding system? Looks to be in good condition, and If it's over 6 months old then I suspect you have a bad connection to the bonding system.

I think ones is a zinc the the captain said the one to port looks like a dyna(sp) plate ...Russ

Both have wires connected to them. Port has 2 wires and Starboard has one. Both look to have been there for years. The starboard one is in much worse shape than the port.

Would grounding plates be on the transom on the B25? There are no plates on the bottom.

Joe, Where do the wires go? Agree with Russ at this point.

Joe,
The port side looks like a Dyna Plate and the starboard is a transom zinc with extra screws, the rudder tab zinc is also shot. I would have someone who knows about bonding systems look at your boat. Check out all of your thru hull fittings on the inside if they have a red or orange tint you got a bonding problem or stray current corrosion. If the thru hulls are green and heavely corroded your bonding system isn't working. Either way have someone check your bonding system, it can sink your boat if not taken care of.
Pete Fallon

If one of them has a bronze color to her it is a Dynaplate.

Pete,

The rudder zincs along with the shaft and trim tab zincs were replaced before launching and showed minimal wear over the season before hurricane Sandy. She has been on the hard since, but will be launched again in a couple of weeks. This was an older picture taken before I bought her. The previous owner never replaced these items in the 7 years that he owned her, he just said don't paint them. Well, I knew that. But I want to replace them before launching this year and want to buy the right products for the job. The through hulls look ok.

So I guess I'll be buying a dynaplate and a transom zinc, along with all new zincs on the rudders, shafts and trim tabs. And in the heat exchangers on the engines.

I'll look at the bonding as soon as I get a chance, maybe later today after client meetings.

Tony, there is no gold color on the Dynaplate. probably wore off as they seem to have been on the boat a long time.

Joe you may not have to replace the dyna plate . give it a swipe with some sand paper if it comes up bronze you should be good to go.I don't have one on my current boat, but other ones I did. It is used to ground the electronics, and is usually found in the bottom of the hull..Russ

Thanks Russ. I'll try that this weekend.

Curious ,we used dynaplates as ground for the old ship to shore radios and single side bands, these do not appear to have any sacrificial value as a zink anode unless it's not hooked up to anything currently, never thought the metallurgy was sacrificial,those look new

Joe/Marlin,
The DynaPlates were made of a gold/bronze beading surface material, They were used for earth grounds for the older LORAN A's, LORAN' C's and SSB radios. They were not cheap when I was installing electronics back in the early 80's, over $100.00 back then. I have installed 100's of them, they had 2-1/4-20 bronze screws that were drilled thru the hull bottom and the electronic components were attached via a mesh copper or stainless steel flat braided cable. I have one on my boat that has been on the bottom for over 35 years and still looks almost like new. You can clean them up using a stiff wire brush, but do it very gently you don't want to remove hardly any material. I have mine hooked up to my old NorthStar 951x GPS and my ICOM 504 VHF radio, I have no problems picking up satellites on the GPS. Joe I would really have someone that knows electronics look at you bonding system, look for any missing or loose drops off of the main bonding connector, wether it's a copper strap or a #8AWG green wire, you can loose you thru hull fittings real quick if they are not protected properly. Marlin, did you get the survey of your 3' Bertram I sent it a few weeks ago as a PDF file?
Pete Fallon

Peter, thx for The update, i also installed many when I was in the boat sales business, but only for the old radios, couldn't spell gps then, interesting that u can pick up data from using the plate, no other gps antenna, got the survey, changing all my boats to a single agent that is savye on marine liabilities, I have 4in the south and 5in the north,actually just in procees of buying a 1954 18' chris craft cobra, all original , concerned about the bottom, I generally flip them over and install a cold molded bottom , this boat is so rare as it's totally original ,dilemma , adding to my wooden fleet, put the 29' hinkley up in Stuart , river forest marine , running the wahoo up when the ocean lays down and the rybo will go there after she goes to the various boat doctors, she has been in the Bahamas all winter, for the summer,air conditioned ,hurricane proof building that complies with the hurricane plan required on higher valve boats down hear,l
Keep us posted on your knee ,thx again for your professional assistance,