Tower base

I am adding a tower to my boat and have a small issue. The base of the tower I have isn't completely flat, it has and arc to it. Also, my boats gunnel is flat then begins to round. I need to make a sort of base plate for the two to have full contact I was thinking of using an epoxy putty and form the sides once squished into place. Any suggestions or experience with something like this out there?

Derek

The points on the tower that contract the boat where bolts would be running through the fiberglass, is there a good surface/contact there?

Without seeing the tower / boat connection point, its hard to say. Someone smarter than I may know, but could that arc be there on purpose to help absorb shock in the tower and not transfer it to the fiberglass / bolts? Is that arc supposed to be off the fiberglass? Again, without a photos its hard to say.

Can you take a pic of were your talking about?

I didn't have the time to take pictures last night since my boat is all covered up and still sorrounded by snow so I sketched it out this morning. The tower is a factory tower for a newer boat that I narrowed in order to fit my boat. Even the factory tower as a plate where I plan to make one. See pictures.

Sorry for the rotated picture. Here is the picture of factory.

If you get no other inputs, and if this were my own job, I'd be doing what you're thinking.

Looking at your colored drawing, I would think that the blue "filler" would be pretty necessary for good distribution of the load between the base of the tower and the top of the gunwhale. But how would I contour the profile of the upper surface. I have a lot of machinists at my disposal. Without them, I do it by hand. I'd pick a soft aluminum plate, a belt sander machine, and a lot of emery cloth (or the like) with an adhesive back. I'd rough shape the upper surface profile on the belt sander. I'd finish by tacking the adhesive backed emery cloth in the channel of the base of the tower, and sand it off by hand to match the channel of the base of the tower.

I'd also do this. Between the base of the filler and top of the gunwhale, I'd put a thin sheet of (tough) elastomeric material. Silicone rubber? SBR? I'd have to think about that after some research.

More importantly, between the undersurface of the gunwhale and your washers and nuts, I'd build an elongated plate to elongate the distribution of stress introduced by the washers, to over a much greater contact area across the underside of the gunwhale.

I'm pondering what I'd do at the interface between the filler's upper 'profiled' surface and the tower base's channel. I'd like to lock them solid somehow. Fasteners?

Anyway, there's some food for thought.

Regarding adhesive-backed anything and then the desire to get rid of the adhesive gum afterwords ... think that through before hand.

One sure way to get rid of left-over adhesive gum on aluminum is to sand it. The other is to use solvents. Every tough adhesive has a powerful solvent to liquify it ... which solvent you shouldn't touch, you shouldn't breathe ... and ... you shouldn't even look at (inasmuch as you don't want the vapors in contact with your eyes anymore than the linings of your breathing passageways).

Again, I agree with your inclination that you should make a filler.

Doing so by 3D printing? I'm a generation too old to give that any thought.

But soft aluminum? The forces your filler is being asked to handle seem to me ... thinking about it as long a I have for this short while ... are predominantly compressive forces. An aluminum grade that sands down readily to make your filler should ... I would think ... be fine.

When selecting stainless for various properties, I always refer to McMaster-Carr. I think I recall there is a similar comparison page for aluminum, but it's just not as clear ... or ... the distinctions between aluminum grades are not as clearly delineated or as clearly understood ... as for stainless. (As an aside, a lot of stainless rusts ... and terribly ... the definition is based -- iirc -- on Chromium content.)

Thanks for the input guys.

So this is what I was thinking of using. Has a compressive strength of over 13k psi and as a putty I can squish it between the two surfaces for perfect coverage then trim away the excess and even sand and paint after if needed for ascetics.

http://www.devcon.com/products/produ...m?familyid=124

Titanium putty? That's some cool stuff. Way to do your research! Would love to hear how it goes w/ the putty, very curious to hear a first hand account of how it is to work with and how it holds up. Good luck with the project!

Thanks. I will keep this thread updated.

Here isa pic of my boat with the tower on it. Still need to complete the "base". Unfortunately I didn't take any close up pictures of the two.

Grind the arc out of the base to make it flat

FWIW - I would move the tower back slightly from where you have it positioned now. I would want to make sure there is enough room for the driver / passenger to be able to reach down to the water between the windshield and the tower. Just my $.02