That Tent
If, when you are making your boat tent, you want a “Quicky-Cheapy” one, look under "Covers" in Practical Boat Owner for the name Fawcetts. We did. A 9' by 12' is about £6 in lightweight plasticy material; totally waterproof. An eyelet kit from any camping shop, scissors and a co-operative seamstress (Crew) and you are in business.
It is a relatively easy job to drape said cover over your boom on its centre line and tailor as you want it, cutting off any gash material to make your ends, etc. The covers come in blue, green and transparent material.
Treble up your material where you eyelet, to give a meaty grip. One small fault in a wind is that the material crackles a bit ... but in the rain, really waterproof. It rolls up very small and is cheap, and gives good experience for when you make your posh canvas one.
Having made your tent to fit your boat, assuming an overboom type using the gooseneck one end and crutches the other, comes the problem of how best to seal the joint between boat and canvas in the gunwale area to keep out the draughts. After some experiments we decided to use ¼" diameter Aero Elastic. Holt Allen (HA 148) plastic lacing hooks were screwed under the gunwale at 12" intervals, including the deck in front of the washboards.
The tent was offered up to the boat and carefully marked at the hook points. Eyelets were punched 12" either side of these points in pairs. The Aero Elastic was then threaded through, creating a series of small loops to hook onto the lacing hooks. The two ends can finish at the transom to be tensioned to give a really tight seal around the boat. The elastic is not bulky and stays on the tent all the while. It can be knotted, or use a pair of "Ingle Clips" ... for quickness.
Should one use battens, "covered wagon" style...? What to use? We found ¾" wide electrical plastic Ovalo conduit a fair solution. Used with the joiners of the same material, the tent needs no modifications other than inside ties to hold the plastic in place. Two things here - 3 x 10' lengths in a dinghy are a bit uncontrollable when not in use, so we cut them in half, glued one joiner to one end, and fix together under the boom; no bother. An added bonus - if you bust or lose a sail batten, cut the conduit to length, tape each end, and you have an excellent batten.