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Making a Sail my Puddle Duck Racer

Here are links to other steps of the Puddle Duck Build

My Chosen Rig is a Leg O' Mutton Sprit Sail


There is no agreement about what to call this sail. It gets all kinds of names including Sprit, Leg of Mutton, Sprit Boom Rig and Sprit Boom Sail.

What is generally well agreed on is that the sail is a simple effective one. It is well behaved and the boom is out of the way, too high to clunk its crew. The foot of the sail acts as a vang and prevents the boom/sprit from lifting.

By tightening or loosening the sprit, the sail can be shaped easily as required.

Its main fault is in the difficulty in reefing. Either the sailor has to lower the sail and tie reefs along the luff and then raise the sail again, or roll the luff on the mast and tie it. OR the sail can be reduced by reducing from the foot and attaching the sprit higher up for new tack and clew positions.

Another fault of the sail is that there is a good and a bad tack. In the bad tack the sail is forced onto the sprit and the shape is not as good as when the sprit does not interfere with the sail shape.

My 4 sided Skerry sprit sail has the same problem but in when in use the difference is allmost not noticeable and in some points of sail the "bad" tack is better. I don't know why.

The sail performs well going upwind but is not as good as a square sail going downwind.

leg o mutton sail

This yellow sail is a handsome sail (photo courtesy of Shorty Rooth) which has proved one of the fastest rig ever to be put on a Puddle duck. It is shown with the sprit on the bad tack. This sail slips on top of the mast in a sewn sleeve rather than beeing laced on.


mast on grass

It took a bit of time to figure out the size and shape of the sail. I used the mast and sprit and tied them in various spots to see what would work best. I knew that the mast partner was just over a foot above the bottom of the boat so I added a couple of inches and called this the bottom of the sail. The TACK.

Since I wanted to use the whole of the height of the mast the HEAD was easy, it was just below the hole I had made in the mast top.

I next decided where I wanted the sprit to cross the mast. This should be a comfortable height to access the sprit. I went for about 4.5 feet from the bottom of the boat.


marking the tarp

The sprit is generally parallel to the water and at right angle to the mast.

I tied everything up. The mast bent a little as it would in use. It was an easy matter to trace this on my polytarp. I used dry erasable markers to write on the sail and the marks can be rubbed off mostly.


sail is marked

I added enough to roll the edges and reinforce the sail. I'm hoping I don't have to add any extra strip of material to the edges. In particular the foot of the sail can be pulled quite tight as it stops the sprit from lifting. I've added 3 inches extra all around. I also have extra material for the corner patches.


cat on sail sail is marked

After a surprise visit from the quality control inspector, I was able to cut the sail and put away the rest of the tarp. I have enough material for another sail if this one needs tweaking.


dandelion dust on sail

When I lifted the tarp/sail from the grass I found that the dandelions had stained the white tarp. Hopefully when everything dries off I'll be able to brush the yellow off.

I'm not going after the dandelions because the honey bees love them so much.


corners of the sail

First step was to cut and sew in the corner reinforcement. It's quite thin nasty poly and I put 4 layers in the corners. Without a bit of thickness there the grommets just pull out as the fabric stretches.


edges have been sewn

The next step is to finish the edges. I had left 3 inches of fabric all around and this was folded and sewn with a zig-zag stitch. I'm using heavy duty polyester thread I bought from Sailrite. The edge is 4 layers thick.

After sewing all around I cut the points off the corners and rounded these. I then zig-zagged over the corner a couple of times.

I decided where I wanted grommets and made small marks.


making holes with soldering irongrommet

I've found that polytarps are really easy to melt and a soldering iron makes a nice hole for the grommets and sort of re-enforces the edges. I stick the grommet while the hole is still melted and quickly hammer the grommet back. It sets it very nicely.

I had cut little squares from the edge of the leftover tarp where the original tarp grommets were set. It's a bit thicker there. These were sewn in the edge where the mast lacing grommets are located.

I'll use the sail before deciding where to put the reefing spots.

I was very annoyed to find that grommets being sold in Canadian Tire are now plated steel rather than brass. I had to go to an upholstery guy to get brass ones. Not so many boat shops in Ridgeway.


sail is up

I took the Puddle Duck out and tried the sail on. I laced it and roughly tied the sprit on. The sail sets very nicely. The mast is quite bendy. I expected it to be stiffer. I don't think that's a problem. The sail is just over 54 square feet.

The knot I made to hold the sprit on the mast slipped and the sprit dropped a few inches. I will make a more permanent attachment when I rig it for real.

The sprit and mast are long enough that if I want to make a slightly larger sail that would be no problem.

Speed is really a non issue for me particularly in a Puddle Duck. I don't suppose it will ever be raced.

All I have left to do now is put a finish on the rudder and daggerboard, make a tiller and rig her. I could be in the water next week.

Sail revew after testing

I've now tested this rig in very light and quite windy conditions and found it to be very nice to sail. The boat ghosted quite well in almost no wind and the sail was wonderfully easy to control in nasty gusty conditions. It sailed upwind surprisingly well, better than my Skerry when I'm not using the jib. It was so windy that my also experimental mast broke at the partner. I was able to rig the remaining mast and get to shore with no trouble whatsoever. This boat is very trustworthy!


I've now made quite a number of experimental sails here is a link to My Sails.


emails: Christine

This web site reflects my personal ideas and doesn't represent anyone else's point of view.