Chessie flyer centerboard pin

Dinghies, day sailers, world cruisers. Many small sailboats make ideal rowboats or low-speed power boats.

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Alf B
Posts: 5
Joined: Sat Jun 30, 2018 9:28 pm
Location: West coast Canada's Gulf Islands

Chessie flyer centerboard pin

Post by Alf B » Fri Jul 06, 2018 9:26 pm

Hello,

I started building the Chessie Flyer last month. Frames are mounted on the building frame, stem & sternpost with breast hooks made, and now working on the centerboard trunk and keel. Never having had a centerboarder before, I am curious about the plan specifying a "standard steel" pin. I know some old-timers that claim black iron will outlast galvanized, as well as stainless, in a continuously submerged salt water situation. With the board being sheet steel, I can see that a bronze pin might be a galvanic problem. I would love to hear from anyone that has direct experience with this, and how it worked out over time.
Thanks,
-Alf

GL3z
Posts: 7
Joined: Sun Sep 16, 2018 8:48 am

Re: Chessie flyer centerboard pin

Post by GL3z » Tue Sep 18, 2018 12:00 am

any updates?

Alf B
Posts: 5
Joined: Sat Jun 30, 2018 9:28 pm
Location: West coast Canada's Gulf Islands

Re: Chessie flyer centerboard pin

Post by Alf B » Wed Sep 19, 2018 8:29 pm

Hi GL3z,

The Chessie Flyer is well under way. I have pictures that I will upload to a new blog as soon as I can get around to it.

mrfixit
Posts: 2
Joined: Fri Oct 05, 2018 7:40 pm

Re: Chessie flyer centerboard pin

Post by mrfixit » Mon Oct 08, 2018 9:22 am

Hi,

I spent some time thinking about this... I am interested in building the Chessie Flyer and have the study prints (have not yet bought the full set).

If you are really concerned about galvanic corrosion, you might use a bronze pin and a sleeve of nylon or other durable polymer to electrically isolate the pin and the steel centerboard. That seems practical if the hole in the centerboard can be made a bit oversize. Like so many ideas it is easier to suggest than to execute.

Otherwise a steel pin is probably the best bet in my mind. The steel pin specified should have a significant corrosion allowance. If it was stainless, the stainless will either be in a passive state (has a very thin coating of oxide) or it will be active (unable to create a coating of oxide, often the case when oxygen is excluded). If it is passive, it will be more noble and tend to cause galvanic corrosion. If is is active, galvanic corrosion is less of an issue but it corrodes like regular steel.

Let us know what you decide!

Bob

Alf B
Posts: 5
Joined: Sat Jun 30, 2018 9:28 pm
Location: West coast Canada's Gulf Islands

Re: Chessie flyer centerboard pin

Post by Alf B » Sun Jan 27, 2019 9:17 pm

Having a rethink about this. The steel centerboard just seems like a maintenance nightmare in a most inaccessible space. Also, there is the danger of the lifting cable and/or fittings failing at some point...that 480 lb. plate swinging freely downward would continue to the sea bed, most likely leaving a big hole in the bottom of the boat. Another consideration is that the stability calculations were almost certainly done with the board down, meaning with the board up the boat may not have positive righting from a 90 degree knockdown.

I'm thinking of having all the ballast internal, well secured, and the centerboard laminated of 4 layers 9mm ply with just enough lead built in at the tip to keep the board down. The pivot hole would be a cast epoxy/glass bushing, with a silicone bronze pin going through. No corrosion, no heavy lifting gear, and I can do it all easily at home. The catch is figuring out how much ballast would be needed with all of it internal, to maintain the positive righting from 90 degrees. There could be a negative performance factor if it takes much more total ballast, than as designed.

My problem is being somewhat mathematically challenged...is there anyone on this forum that can do stability calculations?

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