Radar mast mount from fiberglass?

szigi · #1 03-01-2013

Is it a weird idea? I'm planning to install an older Raymarine Pathfinder unit, which I got for peanuts as not working and repaired it. Any decent aluminum or stainless steel mast mount would probably cost much more then the whole unit did, but besides that my driving force is that I like DIY challenges.

So I am planning on creating a custom mast mount from fiberglass (probably from glassed plywood ), which would nicely be streamlined around the scanner and the mast. I've seen radar arches and mounts for powerboats from plywood or fiberglass, but never seen such a mast mount. Is there something against it? Has anyone done something like that before?

P35juniper · #2 03-01-2013

I would be thinking it would be easiest to mount it on a spreader, might need to reinforce it a bit depending on design and a bit of a mount plate

Lake Superior Sailor · #3 03-01-2013

Read the manual there is a chapter on how the mount & why!

Faster · #4 03-01-2013

I think the durability would be an issue.. Radars - esp older larger ones are not light. Sailboats' mast mounted radomes are subjected to much higher moments and stresses than powerboat radars. A molded glass mount would be preferred to glassed over ply, IMO.

But by the time you've engineered all that you may find buying a factory mount kit not such a bad deal, esp if you find one used.

szigi · #5 03-01-2013

Quote:

Originally Posted by Faster

I think the durability would be an issue.. Radars - esp older larger ones are not light. Sailboats' mast mounted radomes are subjected to much higher moments and stresses than powerboat radars. A molded glass mount would be preferred to glassed over ply, IMO.

But by the time you've engineered all that you may find buying a factory mount kit not such a bad deal, esp if you find one used.

Yah, that makes sense. It's easy to get a factory mount, I was just thinking about having some "unconventional" stuff on the boat. But right, that might happen to be unreliable on the long run and having the scanner falling on my head is not that fun

Thanks for the responses.

meteuz · #6 03-01-2013

I don't think a cored fiberglass mount is bad idea. You might want to consider balsa core rather than plywood to keep down the weight aloft. If properly designed and sealed where fasteners penetrate the skin, I don't think longevity is an issue. This should not be brain surgery; all you ask of it is to hold a certain amount of weight. If it were me, I would not think twice about eye balling the design.

szigi · #7 03-01-2013

Quote:

Originally Posted by meteuz

I don't think a cored fiberglass mount is bad idea. You might want to consider balsa core rather than plywood to keep down the weight aloft. If properly designed and sealed where fasteners penetrate the skin, I don't think longevity is an issue. This should not be brain surgery; all you ask of it is to hold a certain amount of weight. If it were me, I would not think twice about eye balling the design.

Balsa core. That is a good idea! Or it could even be cut from urethane foam panels.
Sure all holes for fasteners would be oversize, and filled with thickened epoxy, as it should be with other cored stuff. I'll make some calculations on the weight and strength, and see what comes out I've been thinking about the stress caused by movement, and the flexibility of fiberglass may even be an advantage. provided the mounting points are strong enough to not crack.

chef2sail · #8 03-01-2013

Quote:

Originally Posted by szigi

Balsa core. That is a good idea! Or it could even be cut from urethane foam panels.
Sure all holes for fasteners would be oversize, and filled with thickened epoxy, as it should be with other cored stuff. I'll make some calculations on the weight and strength, and see what comes out I've been thinking about the stress caused by movement, and the flexibility of fiberglass may even be an advantage. provided the mounting points are strong enough to not crack.

No sharp edges or burrs or you be sewing your mainsail. Most of these are around $250 new, and Ill bet if you call a place like Bacins in Annapolis, MD they have used ones cheaper.

As Faster mentioned, even the new ones are somewhat heavy and I dont think placing it out on a spreader is neccessarily a good idea for balance or weight. Usually they are on the mast or like ours on a radar pole on the stern of the boat. Or radar pole has a closed hoop over the radar dome that serves as the anttannae mount for the GPS, stern light,TV anatannae and also the attachement for our dinghy engine hoist.