Jack Plate metal thickness

[dayton525]

I am mounting a long shaft motor on a short shaft transom. Is 1/8" 3x3 aluminum angle with 3- 3/4" pieces of plywood strong enough for a Mercury 25hp ob? I plan on building it like this http://www.catfish1.com/forums/f184/how-i-built-jack-plate-my-catfish-boat-38827.html
Any input would be appreciated.

 

[JustJason]

Re: Jack Plate metal thickness

A standard transom is 2 to 2 1/2 thick, so your okay by sandwiching/glueing up 3 pieces of 3/4. But aluminum isn't as strong as you think it is, especially at 1/8th. That could be a concern.
Personally i'd do iron instead and just give it a couple coats of primer and paint to protect it.

 

[Bob_VT]

Re: Jack Plate metal thickness

I work with allot of aluminum........ if you use 1/8" you may have a catastrophic failure ......... you need steel or 1/4" x 3 x 4 angle aluminum

 

[5150abf]

Re: Jack Plate metal thickness

Concur, 1/8 is way to thin to hold a motor, that is good design in the link but the angle he is using looks like 3/16 or better.

If there is a MSC locally they may have thicker angle you can use or contact a local weld shop, they can usually get whatever metal you need.

What ever you come up with it should be able to hold your weight standing on the cav plate.

 

[crablegs]

Re: Jack Plate metal thickness

Wouldnt the stainless bolts react with the aluminum too?