Is this the one you purchased yobuck???
Quick Release Bracket / MKA-21[/QUOTE]
No, that's not it either, mine is white in color like the motor.
The larger top part is attached to the motor and is 19" long, and the whole thing is some type of acrylic.
I cant see the part on the boat without removing the motor, but it is about 12" and the connecting pin is 9 1/4" long.
It is also heavier gauge with the hole large enough for a standard size padlock, not a small lynch pin like the one you show. As I recall it cost about $90 as a separate item when I bought the motor, which I bought online at a place called the Minn Kota factory store, or maybe Minn Kota factory direct. Anyway I found out later they aren't affiliated with Minn Kota.
I would call the Minn Kota factory directly, and talk with a tech rep. For sure they can set you straight on any issue you have involving their products.
Well as for the acrylics, there are different types being used in many applications needing more strength than these things. Although the salt aspect might be involved here also.
I don't see why having just one wouldn't do, with just the boat part made for the second boat. That could easily be fabricated from aluminum, as its nothing but a plate with a couple holes for the connecting pin, and a couple others for screwing it to the boat.