Making a Bimini click here to read or make an observation about this  article
By Gary Blankenship & Helen Snell - Tallahassee, Florida - USA
click to enlarge

Until now, I never seemed to have the right boat to avoid the relentless Florida sun.

(click images to enlarge)

Turning toasty under a relentless Florida sun will engender lots of thoughts about the advantages of sailing with a bimini. But somehow, I never seemed to have the right boat for that luxury. Daysailers were too small. An old 24-foot sloop required ducking under the boom at every tack. The sheet leads on our 30-foot balanced lugger were wrong (well, it has a bimini but it’s only usable under power).

But the boom on our 20-foot boat (also a balanced lugger) is high enough to allow a bimini, and the mainsheet is far enough aft to make it feasible. When Chuck Leinweber at Duckworks provided the mounting and other necessary hardware and a small bit of technical advice, the scales tipped.

Some of the hardware from Duckworks.

click to enlarge

To my surprise, the whole job cost around $40, without any of the makeshift jury rigging I sometimes try to save money, and was remarkably easy.

The part that had always inhibited me from trying this was bending the pipe or tubing for the awning supports. Chuck had the easy answer – get a conduit pipe bender from the local hardware or home improvement store. We were lucky and found one on sale for $10; otherwise, they go for about $30 or so. You might have a friend you can borrow one from (and in which case you can subtract that $10 from our $40 estimate)..

click to enlarge

In my “Man of Aluminum” pose, I use the conduit bender to begin bending the tubing for the bimini supports.

Since the hardware we got from Duckworks required 3/4-inch outside diameter pipe or tubing, “inexpensive” alternatives like PVC pipe were out anyway, since the ½-inch inside diameter PVC pipe proved too big, and would be too flexible anyway.. A local metal shop provided the type 6061 aluminum tubing, recommended for outside use. A 20-foot order, cut into 11 and nine foot pieces, came to $22. For our Jim Michalak-design Frolic2, Oaracle, and its crew of average height, they turned out to be exactly the right size, and I had no more cutting to do.

Calculating the size you need for the awning supports is a bit beyond the reach of this article, and of course will differ from boat to boat. So see the speadsheet Chuck has published on how to figure those lengths. (this is a zipped file containing 'bimini1.exe', a bimini calculator. I don't think it has any malware associated with it, but I can't guarantee it - chuck)

The photos show a rather small bimini, only about three feet long and supporting by two sections of tubing. That’s because Oaracle is fairly light and unballasted and I’m worried about balance under sail and stability if the wind gets gusty. It will be easy to enlarge it, if experience justifies it, by adding a third awning support. The tube mounded to the gunwales will then be vertical, with the other supports being mounted on it and hinging fore and aft.

It’s a bit hard to see the bent part here, but the bending is nearly complete. It took less effort than it looks like in this shot.

click to enlarge

I thought bending the tubing would be the trickiest part. It was the easiest; figuring out out where to bend it was the head scratcher. My conduit bender uses 7 inches of tubing to bend a 90 degree angle. With an approximately 60 inch beam, if you mark a centerline, and then 23 inches out each way (30 inches minus the 7 inches), you’ll wind up several inches too short. The mathematical way to figure this is with this formula: Pi times the diameter of the circle equals the circumference of the circle. If one quarter of the circle is 7 inches, that means the circumference is 28 inches. Divide that by Pi (3.14) and then by 2 to get the radius; the difference between the radius and 7 inches tells you where to start bending. That’s the way I did it and it worked okay. Be aware that any bender you use may have a different radius. And some benders have instructions on the side. In practice, I think just laying the tubing across the cockpit and the sliding the bender back and forth will give you a plenty accurate idea.
Although I wound up not needed it, most builders will probably need a hack saw or tubing cutter to cut the tubing to its final size.

One further thought: I made my supports an inch or so wider than necessary. The slight bending necessary to bring the tubing to the cockpit sides puts a slight curve in the top of the tubing, which helps the binimi shed water.

click to enlarge

The hardware was easy to install with just a screwdriver.

Bending the tubing was, as mentioned before, simple. Even working deliberately, it was a matter of a few seconds for each leg. Small adjustments in angle are easy. If the two legs on one piece wind up slightly splayed (like mine), simply brace one leg and twist the other until they match.

Sewing the bimini top also was easy. A wide variety of materials will do, Sunbrella, marine vinyl, and many types of canvas. I choose a waterproof nylon for it’s lighter weight. It also conveniently came in 60-inch widths, which saved cutting and sewing a seam to match the width of the boat. As mentioned earlier, a three-foot length was selected for the bimini. It was only necessary to cut that width, plus extra for hemming and a 1-1/4-inch wide sleeve on each end for the tubing (the circumference of the 3/4-inch tubing is a bit over two inches.

The finished bimini provides some welcome shade from the Florida sun. It may be enlarged if the boat proves to be able to handle a bigger awning.

click to enlarge

The hallmark of gear sold by Duckworks is its simplicity and functionality. So it is with the bimni hardware. It’s only a matter of sliding it in place and tightening bolts or installing screws – trying to explain it in detail will likely only cloud the issue. (The gear is, in fact, much better than the hardware on the many-times-more-expensive bimini I bought for the 30-footer). Three-sixteenths braided nylon line is used to support the bimini while it is up; Oaracle has an abundance of cleats, eyestraps and other gear to anchor the lines.

One final thought. Give careful planning to the placement of the bimini, not only where the bimini is while it’s up, but where it is when folded down. The location on Oaracle allows the sheet to clear the supports while it is up, and when it is down it still allows access to the hatch over the stern storage area.

Other articles by Gary Blankenship & Helen Snell: