I am going to make one with glass - how many layers (6 oz) of cloth do you think I would need?

as many as you can afford

no need to make it light, just make it sturdy.

How do you propose to make one from fiberglass? Are you going to make a mold first? It would be cheaper to glass over the mold (plywood box?) and use it as your sailbox. The top, bottom and sides of my sailbox are glassed with two layers over plywood. These overlap at the corners and edges giving 4 layers of strength. It was a messy job but will be worth it in the long run. Just be prepared to burn up a couple of sanders

You really only need one layer of glass if you're going over external grade ply. But if you're not just wanting to practice your glass skills, consider these options:

- the good old 'PVC pipe'. Durable, relatively cheap if you know how to look for it. There has been a hurricane or two, and there well might be stuff lying about.

- Connected with a fabrication shop? Have a box made if you can get next to a metal brake... actually, if you have a friend who would also like a box, by the time you buy the material for one, it's prolly about the same price to do two and you can share the cost.

- Consider finding a used back-of-truck tool box and refabbing it to your needs. Dividers can be easily cut out with an angle grinder.

http://tinyurl.com/9tsd4

If this link worx, this is a pic of a metal box fabbed for me years ago. Only the ends, hinges and catches are welded. It would be just as easy to do a rectangular version

If you guys are interested, I've got a line on some 10' aluminum boxes and have a few being made this spring. PM me if you want more detail.

I am going to use cardboard tubes (the ones you put into the ground to provide a mold for concrete) as a mold. They are really cheap and the right size. I will wrap them in plastic so i can take the tube out - the cardboard just would become nasty if I left it in.

I assume you're talking about easing the cardboard out of a fiberglass shell? That's probably going to be difficult even with a plastic barrier. I did, however, see a Discovery special on rocket building where some guys used a cardboard tube as a mold for a carbon tube. After the carbon cured, they put the whole thing in a pool and left if for quite some time, then came back and peeled out the cardboard.

Too bad I couldn't just dip the whole thing in epoxy!
I guess the fiberglass does shrink a little when curing so it could be a problem getting the tube out.

This was on TheBeachcats.

http://www.thebeachcats.com/modules...&mode=thread&order=0&thold=0

Make it then, glass over it.

Doug

Consider this as an option.
You could run a cut down the mould. Just one side top to bottom. Insert a narrow piece of timber say 1/2 inch wide and full length of the cardboard mould. Put props in from the 1/2 timber it to the other side of the mould to hold the 1/2 timber in place.
Cover the outside of the join with packing tape.
(Now you have a collapsable mandrel.)
Do your glassing. Once cured pull out the props and then the 1/2 inch timber. Now your moud is 1/2 inch smaller than the
layup and comes out easy.

Hope this helps.
Regards,
Phill

Beautiful.

Jake,

I intend to experiment making a snuffer tube this way over plastic pipe but using 1/8 inch aluminium instead of the 1/2 timber.
I have some very thin closed cell foam that will bend around the tube. So It could be made very light without going to carbon. Just sandwich layup using glass. That way it would still be F18 legal.
I'll pull the sandwich layup down with a vacuum to ensure the structure does not delaminate with time.

Another couple of options (assuming you are not going to get it wet).

1, Use circular tube Aircon ducting (can be bought in a number of sizes up to about 2 foot Dia I think) - I'm planning to investigate this for my next "box" as it is light and fairly strong (being round) and you can buy standard end caps.

2, Use large scale Aircon ducting (rectangle) - hiever than the circular, but will fit the trailer better.

scoob... that is actually a really good call with the ducting. I will investigate...
thanks

When I wanted a trailer box, I talked to my boat's manufacturer. It turns out he already had a mold for one. He had given it to one of the sailors to make his own box. I talked over some modifications with the guy who had it and agreed to pay for materials in exchange for the prototype. The changes included a split top and a drain plug - and I'm happy with both. I moved the box to a double-stack trailer when I bought a second boat and it has room enough for boards, booms, tackle, and sails for both boats.

Regards,
Eric

A good trailer should be able to handle immersion as long as you take reasonable care of it. All the failures I've seen stem from neglect, not immersion. Before launching, you should:

1) Disconnect the trailer lights. Boat trailers are made with submersible lights, but they are not meant to be illuminated underwater. If a hot bulb contacts cold water, it will crack and burn out. You also don't want the water to short out your vehicle lighting and blow a fuse.

2) Always let your trailer sit for at least 15 minutes after towing before launching. It is critically important to let your hubs cool. As you drive down the road, they get warm, and if you dunk them in cold water, the warm air and molten grease inside the hub will contract. That in turn will draw water through the seal into the hub. Once inside, the water will never come out (short of repacking). The bearings will then corrode and fail prematurely.

If you launch in salt water, you need to thoroughly rinse (or better dunk) your trailer in fresh water at the first opportunity. Dried on salt attracts moisture from the air and greatly accelerates corrosion. Your trailer should also have sufficient drainage so as not to trap water.

And, of course, don't neglect basic trailer maintenance, such as regular inspection, checking lights and tire pressure, and annually repacking the bearings.

Regards,
Eric

Eric,
IMHO there is NO good reason to put a beach cat trailer in the water...none, nada, zilch. Even if you go through the proper steps and maintainence. I learned the hard way when I was a newbie back in the day (1975). I had a bearing seize on the 405 freeway in Los Angeles at 10:00 PM on the way to a regatta. Not fun. It was a brand new trailer that I put in the water to launch and retrieve. Never again and I haven't had any problems since (knock on wood) for a quarter of a million miles. Take good care of your equipment and it will take good care of you. Lesson learned.

if you're launching off a concrete ramp, then there's not an easier way to put the boat in the water than dunking the trailer.

Like Eric said, just take care of your stuff and you'll be a-ok.

Afterall, who DOESN'T replace their bearings at least once every two years?

Patrick, If you are not already commited to a design, do a search at www.thebeachcats.com There is a lot of info on the subject, and some great boxes/tubes. I purchased the large glass box from Hobie, and found it more time consuming, and way more expensive than building a plywood box from scratch. The boat I have now came with a nicely built wooden box. Only troubles were it was on the trailer backwards, and too high to get the boat on and off without lifting! I hacked it up a lot modifying it,but now it works great. Tad, after rebuilding the trailer for my first 17, it seems like more work to dunk than not to dunk. I'm with John on that one. Love my Cat Trax!