What to use for transom board on sneakbox

[Jim Mandas]

Hey fellas,

Title says it all. Can I get away with a 2x6 or should I laminate ply for the transom board/ jack plate? My motor’s gotta go up about 6” give or take.

Thank you!
-Jim

 

[Steve Sanford]

Jim~

A bit of clarification: Is this question relative to your Herter's Duck and Goose Boat? If so, I have presumed you would be using the existing transom - most likely with a well in a new stern deck.

I have built many "add-on" motor boards for duckboats - especially South Bay Duckboats - which came from the factory with an external motor board. I have replaced/upgraded them as they aged.

In any event, I use treated 2x10. (I usually have some on hand so it's nice and dry.) I add "stand-offs" to minimize the moisture trapping surface area against the hull. Many of the failed factory boards - usually laminated marine plywood - had rotted against their hulls.

The finished board gets 3 coats of epoxy for a good seal. t is held on with 4 s/s bolts (5/16 or 3/8) - bedded in 3M 5200.



The rounded bottom serves as a handhold - for lifting AND it gives access to the transom drain.



No motor well. Height above the stern deck is critical for motor height on hull. Anti-cavitation plate should be at the bottom of the hull BUT motors vary....



Similarly, the exact spacing of the clamp pads varies - so I make a "keeper" out of 1/8-inch 'glass for the specific motor to be used. It keeps the motor from twisting off (I hope!).



Having said all that - I am wondering why the motor needs to be ~6 inches higher? Is your motor a short shaft? I have no experience with jack plates - so I will defer to others.

Hope this helps!

SJS

 

[Jim Mandas]

Perfect thank you Steve!
Yes, for the Herters. Treated 2x10 with the standoffs, I’ll order one in. I ran a Johnson seahorse 5.5hp which is what I’d like to run with that boat, my water and exhaust discharge port are a good bit underwater, anti cavitation plate is way under the line. I have a 3hp evinrude duck twin that I used with the boat before and it too needed to be raised I think but not quite as much as the Johnson.

Standby, I will send some pics. Thank you!

-Jim

 

[roy brewington]

Sounds like your using a long shaft motor on a short shaft hull. Might want to convert motor to proper length if that's the case. Theres 15" shafts and 20" shafts on small motors.

 

[Jim Mandas]

Hey fellas,

I’m about positive it’s a short shaft motor, Johnson CD-10. Good news is I don’t need to lift it as high as I thought- I think 4” should get the anti cavitation plate level with the bottom of the hull/ transom.

Thank you!
-Jim