When I first got my CM-21 I didn’t know sailing from flying. However, I quickly figured out that the main sheet was located in a very inconvenient location; mounted just outside the cabin in the front of the cockpit.
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| Old Main Sheet Mount |
On the many sailing outings I went on, it became apparent that the original design was cumbersome and limited the overall utility of the boat. The system consisted of a rail, and a block mounted directly aft of the main hatch. The rail allowed the block to slide from port to starboard, giving optimal adjustment to the boom. The main sheet effectively restricted entry to the cabin and limited the sitting space available in the cockpit.
More then once the mainsheet would lock a passenger or myself into a front corner of the cockpit; or when tacking make it difficult for a passenger or myself to switch sides while turning. It was an inconvenient and unacceptable set-up and needed to be addressed. I’m sure other CM-21 owners can appreciate my concerns and have experienced the same.
During my initial period of sailing I had the good fortune to experience other boats and observed how their main sheets were rigged. It seemed to me that there was a wide array of options as to rigging a main sheet. This, I’m sure helped me realize that the CM-21 design could use some improvement.
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| New Main Sheet Mount |
In the spring of 2011, prior to launching the boat for the season, I decided to do the modifications. I had had all winter to contemplate my many options, and decided to go with a simple yet efficient design. I would mount the main sheet off of the aft stay.
I had seen this configuration on another boat and thought that it would lend itself well to my CM-21. It was just a matter of fabricating and mounting the necessary hardware. All I needed to accomplish my modifications were a couple pieces of aluminum and a new block system.
First, I needed a thin rectangular piece of aluminum to make into both an aft stay mount and a connection point for the block. This I found at a local fabrication shop and acquired for free. It was too small a piece of aluminum to have any marketable value, so they just let me have it. Cool. The aluminum piece was 3/8 inch thick, 8 inches long by 3 inches wide. I would have preferred a ¼ inch thick piece, but there were none available.
It took me a couple hours to fabricate the aluminum shank into the shape I had designed. This consisted of cutting, grinding, sanding, and drilling three holes into the piece of metal. When it was all said and done, I was very happy with the end result.
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| Wooden Block |
To make the new fitting attach properly I had to shorten the aft stay by about the same length. I actually shortened it a tad more then the aluminum shank in order to maximize the adjustment potential of the aft stay and to account for the shackles I would need to attach the fitting to the boat.
I also added to the adjustment potential of the aft stay by placing a wooded block or wedge onto the boat. This I fabricated and painted. The wedge is placed between the hull and the aft stay mount; making it possible to adjust the aft stay by a couple inches either way. It also moved the aft stay out another inch and a half making sure that the boom can swing freely. On my boat, I only had a couple inches between the boom and the aft stay in the first place. I wanted to make sure the new modifications would work properly and adding more space seemed to be the answer.
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| New Boom Mount |
Next, I needed to add an attachment point to the end of my boom. This I accomplished by using a long thin piece of aluminum. The only issue was how to attach the new fitting without compromising the existing configuration. The new fitting could not restrict the line used to tighten the foot of the main sail; which pulled through a groove at the end of the boom and is attached to a cleat on the under side.
My solution was to bend the aluminum in half and rivet it to both sides of the boom. I left enough space in the curvature of the bend as not to restrict the tension line of the main sail. In the middle of the bend I drilled a single hole where the main sheet could attach via a shackle.
So far so good, the modifications seemed like they would work. It was at this point in the project I actually spent money. I decided I wanted marine quality hardware to complete the refit of my boat.
I purchased two blocks (one with an attached cleat), a new main sheet, and several stainless steel shackles. I took my new toys home and assembled my new main sheet.
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| Kicking Strap |
It worked just as I had envisioned, opening up the cock pit and eliminating the restriction to the cabin. Soon, I tried it on the water and it proved to be as effective in actual use as it was in my driveway.
Because I had moved the main sheet from the original position, I now needed a kicking strap. In the old configuration this was not necessary, as the main sheet eliminated the boom from lifting. Boom lift was the only consequence of moving the main sheet to the aft of the cock pit. It was an easy fix.
I used my old main sheet and blocks for the kicking strap and attached them to the mast using a climbing wedge. The wedge fit perfectly into the bottom of the mast and eliminated the need to add an attachment point to it.
With the new fittings in place and the addition of a kicking strap my CM-21, the Flying Fish, is ready for action. The cock pit is now more comfortable then ever and the cabin is easily accessed. I am very happy with my most recent modifications. Happy sailing.
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