Alum. pipe size for radar.

sailboy21 · #1 (**permalink**) 09-16-2008

Well... my $40 galvanized fence post radar mast is starting to get ugly after 3 years. Not that it isn't doing its job, but I am getting tired of cleaning rust stains off my gel coat. I still want to go on the cheap, but with something that will be a little more appetizing to the eye and the market value of the boat

. Locally, aluminum pipe (not tube) is about the only choice for me. Anything else in 8' length would cost a fortune and a half to ship up here. I can get a 20' section of sced 40 2" pipe for just over $50 so the price is right in the ballpark. My feeling however is that aluminum will be easier to bend to failure, even though its wall thickness is significantly thicker than that 2.5" steel post. Has anyone had any experience with this type of material?

The base is about 1' of pipe/post U-bolted to the back of my cockpit. About 2 feet from the bottom I tied it in with a small strut to the pushpit. There are no other struts supporting the mast. The fence post has survived 3 years of abuse up to 55 knot winds and associated seas, although it does seem a little flimsy at times. I guess I did a good enough job backing the fiberglass behind the cockpit since no stress cracks have materialized since I put it in. Regards.

Faster · #2 (**permalink**) 09-16-2008

I bought 8 feet of 2" SS heavy wall tube, (cost $60) and used that for our small JRC unit. It is bolted to the toe rail and braced to the top of the stern rail. So far (2 yrs) it is standing up well, does have a bit of flex in a seaway but nothing that has caused concern. The unit only weights 7 lbs or so, so there's as much weight in the tube as up top.

My only regret is it's 304 which in our area needs a lot of attention to keep looking nice.

I suspect aluminium may be stiffer. I also did not want the "vertical" strut look so cut and rewelded it at about a 5 degree aft rake.

ckgreenman · #3 (**permalink**) 09-16-2008

Is it possible to mount to the mast? It looks like you can get a radar mast mount for about $120 or so. I know it's not as cheap as an aluminum pole but i think it would be more permanent.

Faster · #4 (**permalink**) 09-17-2008

I've actually got a mast mount he can have....free. I wanted the display unit at the helm and there wasn't enough cable to go the distance... hence the stern mount.

sailboy21 · #5 (**permalink**) 09-17-2008

There is something about drilling a 1" hole and a series of 1/4" holes in a spar just doesn't feel right.... then trying to figure out how to route the cable through mast steps, bulkheads, settees etc... and 1/2" cable banging around inside the extrusion at anchor. No, quite happy with the radar mast. Plus it gives the GPS antenna and boathook a nice place to perch.

jrd22 · #6 (**permalink**) 09-17-2008

Sailboy- 2" seems a little shy to me, I would think 2.5-3" would be better, although the cost will go up. Alaska Copper and Brass in Seattle sometimes has shorter lengths of aluminum pipe, you might give them a call and ask what they have, also Pacific Industrial Supply (Seattle/Kent?)has a lot of used alum. pipe.

John

ckgreenman · #7 (**permalink**) 09-17-2008

Quote:

Originally Posted by sailboy21

There is something about drilling a 1" hole and a series of 1/4" holes in a spar just doesn't feel right.... then trying to figure out how to route the cable through mast steps, bulkheads, settees etc... and 1/2" cable banging around inside the extrusion at anchor. No, quite happy with the radar mast. Plus it gives the GPS antenna and boathook a nice place to perch.

There's probably tons more holes your mast already with the various cleats, spreaders etc. already attached so I wouldn't think a few more would be an issue, however, the cable routing?? I can see your point. It was just a thought

. As for the Aluminum pipe, I think if it were me I'd either step up to 2.5" schedule 40 or schedule 80. Another option (if you can route the lines) is to find some way to stay the pipe to eliminate some of the flexing.