For a lower cost alternative, you can make a sailbox out of wood for under $100. Now making two, one for trailer, other for storage at Sail Sand Point. Boxes will be 11.5 ft by 2ft, 10in deep. Lid, 3/8in plywood, with 1 by 2 in edge. Sides and bottom 1/2 plywood. 1 by 2in framing with 2 by 4 ends. Paint inside and out with white semigloss exterior paint. Had the last one for over 20years, and sold with H-17 and trailer.
Caleb

Thanks Caleb. What grade of plywood do you use? I wonder about the weight though. Ed

All plywood, exterior grade. Standard construction grade on 1/2, sanded finish on 3/8 lid. Total weight about 150lbs, based on material list. Will weigh after completion.

Caleb

He, he, you said "elegant"...

It's a short length that he attached to the front of the box, pole goes in box and into the protuberance.

I made mine out of 1/4 inch birch ply Framed with 1X2 fir. Wrapped the outside in glass then gel coated it. Two coats of resin on the interior no glass. I put a 2 inch curve in the top for strength. I go 250 and no problems standing on it. Still Strong after 15 years. I backed the trailer into a tree without the boat on it and the 1 1/2 in galvanized support bar bent around the box. More than strong enough. I prefer and lipped slide on lid. You can get the lid out of the way. Get into the box then the boat is on the trailer and water tight.
About $150 in material and 20 hours of labor.

+1

I made mine out of "door skin" laid on a 1" x 1" wood skeleton and "painted" with polyester resin. Sat out in the weather for a few years with no problems. I had hinged doors on each end which rotted on the ends after about 2 years, but those were easily replaceable.

I think the whole shebang cost about $75 a few years back

There are disadvantages to a box thats just too big.

Ever drop a drain plug in there and it rolled to the exact middle of the box? Pain in the butt to get it out!

You can also make a nice, cheap "box" from PVC/plastic pipe- either just a section of pipe w/ wooden ends/plastic end caps (use bunji to keep on or latches) or split pipe and use plywood for "floor"- join in middle to reduce cost and can cut a "hatch" (or two!) and/or wooden ''door" on end.

Kirt

Not sure if I had that happen, but I can see your point. I had the doors on each end so I could open them with the boat on top... Maybe some sort of opening on the top would really facilitate access... But for $75 all in, it was a good temporary solution (this was way before you started making boxes, by the way) for a few years.

Couldn't you just tip the trailer up to help the drain plug roll to the low side?

If you build your own, be mindful of ample clearance for the dolphin striker, at all angles.

Don't ask. . .

Offsetting the box to one side can help with dolphin striker clearance depending on the box- Don't ask me how I know--

Kirt

Correct, put the sailbox to one side. On the other side I put 2 pieces of metal conduit about 16" apart. The cat trax go there. Easy to slide in and out under the boat from the front or back. Tie the trax to the trailer frame, lock with a bike lock.

I've built two different boxes out of wood. (Two different boats and trailers). The first was bascially 3/4 inch marine plywood. Treated 2x4's, SS screws, etc.

Trailer shapes are basically a rectangle with a triangle, or trapezoid on the front end of it.

I always built using all available space, as in the rectangle 4' x 8', by 12" high, with an additional 4' base, by 4' sides, by ~ 2ft front trapezoid. You can keep 2 set of sails, several poles, extra everything, etc. in a bos with this much Sq. Ft.

By second box was built much lighter, out of of 2x2's frame 12' long, x 4' wide (fender to fender), by 12" tall, A series of two doors, that always stayed relatively water tight. I used T=111 treated siding sheets, lasted for years, never rotted. It had a spine in the middle, so you could easily stand on it, dance on it, etc. The guy I sold it to took it off, not really sure why, it was very functional.
It was the the 'table' at many a regatta on the Tx Gulf coast for skippers meetings, award ceremonies, and many an after regatta dinner table, etc.

I always strapped the cat wheels to the bows, underneath in front of the box, lock to the trailer, an never had a problem with it.

You have had some great suggestions, go for it!

I used 1/4" construction grade ply, and aluminum channels for edges and corners. It required some internal bracing. I wanted access when the boat is on the trailer, so there are doors at both ends and a sliding hatch on top at one end. This has not proved entirely satisfactory, due to leakage, but a cheap tarp from Lowe's has solved that.

So check this one out,did it for fun as I do this for a living. It's 1/2" marine ply which is Duglas fir with a better adhisive, ext. is the same but has voids marine has none. It has 1'x1' ribs to make it stronger they are oak and about every 16" the conners are Mahogany as is the door at the rear. The lid opens with a hydrolic piston so it will stay up. The bottom has cedar 1x4 planed down to 1/2' across the 1x1's so as create an air space to keep the sails out of any mositure on the bottom, lets the air circulates around the sails or what ever is inside and is lite as it is heavy enough, also helps keep the bugs out, not that they can get in but you know bugs, a little over built but it will last a life time. The thing was coated with west system epoxy and the 207 or 205 hardener can'y remember it's there best hardener with the UV protecter about 4 coats sanded between each and buffed after but be warned it must still be covered or the sun will eat it up as it did the first time I could paint it but wouldn't be as pretty I'll try a clear allgrip next time and see what happens.

sweet~ and you can be buried in it when your "all done"

Here are a few more pic of the interior as it is trick. And I didn't mention but the 1"x1" ribs are only on the top and bottom and yes you can not only stand on it but do an Irish jig if you so desire.the interior is coated with 2 coats of Helmsman polyurethaine/spar varnish for protection against the moisture. good luck and have fun building yours..
Alex/ Blindmonkey: cause even a blindmonkey can find a banana in the wood every now and again

Well at 12' long and 32" wide it would make a rather large "coffin"!!!!! but it would work LOL. ALex

I don't know if I would ever want to have a sail box that was prettier than my boat.