JEM Watercraft

The way that I did it was to clamp the two together (the two E's facing each other), set it up on the drill press and drilled a 1 1/8" dia hole 5/8" deep, followed by a 3/4" dia hole total depth 1 3/8" deep. Unclamped the two halves; and, drilled the holes for the hold down bolts.

I'm not sure if it is necessary; but, I drilled the drum shaft cradles oversized. I later filled in around the drum shaft with thickened epoxy. (I covered the drum shaft with teflon tape to prevent the epoxy from sticking.) I was concerned that if I only drilled a 1/2" dia. hole, coated it with epoxy; and, if the epoxy becomes worn, water may get into the wood.

An alternate method to filling in around the drum shaft, fill in the 3/4" dia hole areas (separated Part Es) with thicked epoxy. After the epoxy cures, reclamp the two halves together, and drill a 1/2" dia hole to a total depth of 1 5/16".

This looks like it should work well. It will probably take a few seconds more to install or remove the drive as compared to Hobie's cam lock knobs; but, it should secure the drive very well..

I am in US Central Standard Time or UTC - 6. It is now 8:56 PM, Friday, Dec. 17, 2010.

I am thinking along the same lines but I dont have a drill press with a vice to hold ever thing in the right spot. I might have to ring a few mates & see what they have. . . . .

I had re-glued my drive well back together the other day into 2 halves. Glued the "wings" on for the hold downs, cleaned up all the parts & tried it around the Drive today.

It looked good & I was thinking of ways to glue it together & then it happened.

I dropped 1/2 of it on to the concrete floor & smashed the thing to bits

I think what I will do is glue that bit back together & make up my hold down washers, sit it around the drive & then tack the well together. Then once its dry I will wrap it with glass to strengthen it all up.

Did a bit more on my drive well today. No epoxy work as my father in law is very allergic & he will be here for Christmas tea tonight.

I set up my drill press & drilled the resess for the hold down washers.



Drilled them & they came out like this



Then set up again with my largest hole saw.



54mm so I ended up with a 50mm washer



I also drilled the ally washers at the same time.



I intend to sand the ally back to "key" it & then epoxy them to the ply ones & cut the slot into the lot to allow the drive to be removed with out having to take the washer right off the bolt.

I started on another drive well, made parts E and E2, and unloaded some pictures.

http://www.picturetrail.com/sfx/album/view/23618332

From the above picture, it appears that you may have cut the base and the hull larger than the plans. The opening in the hull and the base should be a maximum width of 2 1/2". I designed it this way to increase the strength of the drive well / hull, minimize the hull opening, and to provide a stopping point for when the fins are up against the hull. Yours may be ok still; I just don't know.

I just measured the gap again David & Im a bit less that 1/16" wider than the 2 1/2" but that might explain why I had a slight rub on the front pulley as it look I have the whole well a bit narrow.

The drive fits well & now doesnt rub any where so I think it should be OK.

Yes, it should be ok. I didn't notice the hull / base ledge on your picture earlier. I see it now.

For the rub on the front pulley; I have also noticed a slight variance in dimensions of the four Hobie drives that I have / had. One of the drives also had the drum shaft noticeably off center. I adjusted it to be centered; otherwise, I would have had a rubbing problem. Even though yours is no longer rubbing, do you think that I should increase the width of the drive well; or, did you just make it too narrow?