Sits higher than my previous mount which was mounted under the rear crossbar. The mount under the crossbar caused a lot of splashing, both onto the motor and onto the main tramp, not to mention slowing me down. Total cost was about $100.
Made from 80/20 extruded aluminum.
https://www.8020.net/Top plate is bolted straight through the rear crossbar. (2 5/16"x3" SS bolts)
Bottom plate is smaller and at 1/4" thick, is easily wedged into the slot on the back of the crossbar. SS small set screw to ensure is doesn't pop out if there is some unforeseen upward force on the motor.
Main support leg is 24" long. (bolted through the top and bottom plate by 2 5/16"x 2.5" SS bolts)
Plates bolted to the side of the support leg are only cosmetic to hide the gap between rear crossbar and end of main support leg for the motor. (carriage bolt head slide into the t-slot of the support leg and everything is capped with SS acorn nuts)
Since the anchor point for the main sheet is now buried under the motor mount, I added an eye bolt to anchor the main sheet and also to anchor a safety wire for the motor.
Safety wire is an old forestay bridle.
Wooden mounting plate is bolted using SS carriage bolts and SS acorn nuts.
Three L brackets at the motor end of the main support leg are bolted using SS carriage bolt head slid into the t-slot with SS acorn nuts.
Click on the link below to see photos and video. As you can see, it sits high in the water when stationary but when the prop is engaged, it bears down and digs into the water a little more. Of course this was with only myself on board so a few more passengers and it would be lower in the water also.
https://photos.app.goo.gl/bLCpYZXYTjFqfxRN9Invoice with part numbers are in my photos in the above link. I did place a second order to replace 2 of the 3 four hole L brackets with 3 hole L brackets. 3 Hole L brackets are part number 4376-Black. On the site,
https://www.8020.net/ goto Shop, Fastening Methods, External Fasteners. Then refine the search by 15 series and color black. I also ordered a 28" main support leg as I was not sure exactly how long I needed it. I ended up cutting off 4" to make it an even 24" leg.
So in the end I used:
(1) 4301 4 hole L bracket (used as top bracket at the motor end)
(2) 4376 3 hole L bracket (used as side brackets at the motor end)
(1) 4312 7 hole plate (used on top of rear cross bar)
(1) 4341 4 hole plate (used on bottom of rear cross bar)
(2) 4305 3 hole rectangular plate (used on sides of main support leg for cosmetic purposes and needs to be cut to match the curve of the rear crossbar)
(1) 1515-S main support leg. Only 24" needed. My order was for 28" which I had to cut down.
(2) 2110 t-slot cover 72" (ordered on a separate invoice) to give a more finished look to the main support leg.
All bolts, nuts, and washers are 5/16 inch diameter by 18 threads per inch and are stainless steel. Dimensions listed below are length, except for the set screw.
3" hex head bolts (2) for attaching top plate to crossbar
2 1/2" hex head bolts (2) to hold top plate, main support, and bottom plate together
3/4" carriage bolts (4) to hold the side covers to the main support (2 each)*
3/4" carriage bolts (3) to hold the L-shaped parts to the main support (1 each)*
1" carriage bolts (4) to hold the wood motor bracket to the L-shaped parts (2 to the vertical L and 1 each to the horizontal Ls)
Acorn nuts (15)
Flat washers (30)
Split lock washers (15) - I used Loctite blue threadlocker but you could also use lock washers.
1/4" diameter X 1/2" long set screw to hold the bottom plate in the crossbar