Upgrade Your Main Sheet to Double Ends

“Double your pleasure, double your fun” used to be the Doublemint gum slogan because of its double strength mint flavoring. You can double the utility of your main sheet by upgrading it to double ends. What you already have, a working end at the fiddle block that attaches to the traveler stays as it is and you can continue to use it from the rear of the cockpit. But instead of the opposite end of the sheet terminating at a becket at the boom block, it continues forward along the boom to a swivel block with a cam cleat over the front of the cockpit. This allows you or another crew member to also trim the main sheet from a forward seating position.

The  main sheet tackle and traveler of the Catalina 22 (and similar sailboats) are simple and strong. Their location at the stern of the sailboat leaves the cockpit clear for comfortable cruising, just what it was designed for.

DSCN5789 (Custom)
Original main sheet (left, green), traveler bar, and adjustable backstay (right, white)

This easy upgrade opens up new possibilities without sacrificing that cruising comfort and convenience.
A double-ended main sheet gives you several benefits for cruising or racing:

  • Performance — The C-22 in particular performs best with its weight evenly distributed fore and aft. If you load heavy gear in the lazarettes, add an outboard motor and fuel tank, and sit the skipper in the stern where he can command the tiller and the main sheet, the transom will sit too low in the water with the bow raised. A double-ended main sheet lets the helmsman sit forward in the cockpit and shifts some weight forward, which improves handling.
  • Crew functionality — With a double-ended main sheet, a crew member in the forward cockpit can just as easily trim the main sheet as the helmsman, which allows them to concentrate on the helm and the course.
  • Training — Teaching somebody to trim the main sheet is much easier if they can sit forward in the cockpit  and not crowd the skipper around the tiller. It allows them to focus on the main sheet while the skipper attends to the tiller without another set of knees in the way.

A double-ended main sheet setup simply lets it be trimmed from two locations: the original location at the traveler block or from the front of the cockpit. When you adjust one end of the main sheet, the opposite end remains cleated. Both ends adjust the sheet by the same amount and have the same effect. The only difference besides location is that the traveler end of the main sheet is horizontal and the new end is vertical.

Double-ended mainsheet kit installed on the boom.

To upgrade a single-ended main sheet to be double-ended:

1. Replace the block at the upper end of the main sheet tackle (single sheave with becket) with a double sheave block.

P1020313 (Large)
A double sheave block replaces the original single sheave block with becket

2. Install a swivel block with a cam cleat on the bottom of the boom approximately over the companionway bridge.

P1020315 (Large)
Swivel block with cam cleat installed on the bottom of the boom

3. (Optional) Replace the main sheet with a longer length to provide enough slack for a broad reach from both ends of the main sheet. If you do not replace the sheet with a longer one, you will only be able to use one end of the main sheet at a time. You’ll have to pull all of the slack through the opposite cam cleat to use it from that end.

4. Lead the upper end of the main sheet through the second sheave of the new double sheave block, forward along the boom, through the swivel block and cam cleat, and pull additional working slack.

There’s only one downside to this upgrade. It inconveniently places the swivel block where it is easy to hit your head on it when climbing into or out of the cabin if you aren’t paying attention, earning it the nickname of “head knocker.” However, the dangling end of the main sheet is a good reminder to duck under the swivel block.

A double-ended main sheet is easy to get accustomed to. You can work the wind puffs just like before and cleat the line off for steady sailing. It affords the same mechanical advantage as the original main sheet tackle (3:1). The forward seating position that it enables means that if you sit forward as the helmsman, you’ll need a tiller extension to steer. See Make a Tiller Extension For Better Cockpit Mobility for a DIY project.

When a double-ended main sheet and tiller extension are used together, you can sit all the way at the front of the cockpit, which places your weight over the keel instead of over the rudder. It also puts you in a better position to handle the primary winches and the other sail controls if you have them led aft to the cockpit like I describe in Lead All Lines to the Cockpit for Safer Sailing. Its the best position for single-handed sailing; everything is within arm’s reach.

To make this upgrade as easy as possible, I’ve assembled a kit that includes everything you need. Installation only takes about an hour and you retain your main sheet’s original functionality. For details and to place your order, click this button.

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9 Comments Add yours

  1. Ed in Gig Harbor says:

    Another great modification description! My Venture 21 doesn’t employ a traveler: it is a trianglar arrangement with sheaves that let the main sheet route from the end of the boom to each corner of the transom with a camcleat on the port side just forward of the stern (if that makes any sense for you). Have you seen a double sheet setup for that type of rig?

    1. Hi, Ed

      Your main sheet is already double-ended, sort of. But instead of the ends being fore and aft, yours are port and starboard. About all you could do to improve it would be to move the cam cleats forward to, say, a mid cockpit location and maybe add turning blocks so that you pull the main sheet athwartship instead of forward.

      1. Ed in Gig Harbor says:

        Here is what the ‘owners manual’ (for a later 1980′ version sent by Blue Water Yatchs) says about the mainsheet:

        Attach the double block to the boom end tang with the small shackle. Run the
        mainsheet through the swivel cam cleat block (I’d add:on the port rail), through the forward pulley in the
        double block on the boom, through the pulley on the starboard rail, back through
        the aft pulley on the boom, and tie the end to the deck eye just aft of the swivel
        cam cleat.”

        So, to do something similar to your mod, I could just not return the fixed end back to the deck eye (switch out that double block for two single ones?) and run it forward on the underside of the boom to another swivel block w/camcleat (as you did). Interesting idea…just have to set it up so it plays cleanly…maybe keep that double block, but use the aft pully first, then have the segment returning from the starboard pully use the rear pully and turn off down the boom.


      2. I understand what you mean now and I found a couple different variations for a Crosby rig:

  2. Dan N says:

    Thanks for the write up! I’ve been looking for the “headknocker” block you show, but I haven’t been able to find anything. Can you share the part/source? Thanks!

    1. Hi, Dan

      Harken used to make it under the name 140 Pivoting Big Bullet Exit Block with 150 Cam-Matic but they stopped manufacturing them. However, you can purchase almost the exact same thing as the Viadana Single Ball Bearing Swivel Block w/Cam Cleat 28mm. That is the block that I include in the kit described in $tingy Sailor Double-Ended Main Sheet Upgrade Kit.

      Give double ends a try. I think you’ll like it.

      1. Dan N says:

        I completely missed that you were selling this as a kit! I already have everything I’d need except the headknocker or I’d happily bought it from you. Thanks for the info, I’m keeping it stingy and found the harken part on eBay 😉

  3. dan says:

    This site has some good ideas, but diagrams would really help. When hearing a bout a new concept, or new arrangement of lines or rigging, it’s much easier if there is a nice little diagram. You have a fair amount of detailed photos, which is great, but hard to see big picture.

    1. Point well taken, Dan. In fact, there are many diagrams in my ebook Do It Yourself Small Sailboat Rigging (https://stingysailor.com/ebooks-2/#SmallSailboatRigging) like this one:

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