End boom vs. mid-boom sheeting

Posted by Ralph Naranjo at 06:39PM - Comments: (13)

End-boom sheeting on this Herrshoff "Rozinante" offers more sail-shaping options.

For centuries, a battle between simplicity and sail-trimming efficiency has been waged. Racers love double-ended sheeting that leads to the outboard end of the boom, runs forward internally and exits the boom near the gooseneck, returning aft along the cabin coamings or through a sub deck alleyway. Many bimini-bedecked cruisers appreciate mid-boom sheeting with bails so far forward that the sheet behaves more like a vang/sheet combo.

The right mainsheet solution depends upon your own sailing preference, but a few general principles reign true. The farther forward on the boom the mainsheet is attached, the more of a downward effect (vang-like) sheeting elicits. The resulting elimination of twist may or may not be desirable, but itís part and parcel of the trimming process. Itís no surprise that almost every performance-oriented sailboat is designed with end-boom sheeting.

Another fait accompli of mid-boom sheeting is the increased bending moment this tackle arrangement delivers. Relatively thin-walled tube sectionsósuch as a mast, boom, or spinnaker poleócan handle impressive compression loads, but when it comes to the fulcrum-like bending load linked to the mid-boom attachment of a mainsheet, such tube sections perform poorly. Even with multiple blocks spreading the load over several feet, those converting to mid-boom sheeting will want a boom with a bit more cross-section or wall thickness.

Mid-boom sheeting clears the lines from the cockpit.

Attaching a mid-boom preventer has a similar downside for those sailing coastally in an ocean swell. All it takes is a rolling swell and an inadvertent dip of the outboard end of the boom into green water. With a preventer rigged in the middle of the boom, the unsupported load caused by the contact with the sea can break the boom. This is why many seasoned voyagers have the mainsailís clew-end reef point sewn in higher than the tack, resulting in the elevation of the outboard end of the boom, and making it less likely to submerge; some also lead a preventer to the outboard end of the boom. But if ocean sailing is not in the picture, such encounters are much less likely.

The bottom line is that end-boom sheeting delivers more mainsail control but places the tackle in the cockpit. So if you are satisfied with the sheeting afforded by a mid-boom setup, with its short traveler, at least the cockpit will be free of flying tackle during a jibe, and thereís room to rig a permanent bimini. But if you are about to tackle a mainsheet makeover, itís worth considering whether or not end-boom sheeting might be more up your alley. Thinking about replacing mainsheet tackle, see our mainsheet-tackle test featuring the biggest brands in sailing hardware including Garhauer, Schaefer, Harken, Selden, Antal, and Nautos.†

Comments (13)

Great topic. I sail a 38' Beneteau with a mid-boom sheet attached to the [now ubiquitous] Beneteau white arch. In order to reduce the chance of the boom breaking [I sail her in coastal ocean San Francisco area swells/strong winds that have cracked/destroyed some of the OEM provided main sheet blocks], I use a Walder boom-brake that is attached to a bridle that I've run under the boom, which is itself attached closer to both boom ends. This bridle configuration effectively distributes the load point to the two ends of the boom rather than concentrating it mid-boom.

Posted by: CA Dude | February 28, 2018 8:17 PM    Report this comment

Last year completed ASA101/103 and this is the first discussion I have seen of boom sheeting and the vang. And now that I'm looking for a vessel to buy I now have to factor in these notions that I don't fully understand. I'm hoping this is not the case for the Gemini 105Mc.

Posted by: calicojack | January 23, 2018 1:23 PM    Report this comment

Great article! Regarding the comments about single-handing a mid-boom traveler... that would be me on my ol' 30-footer. A simple vertical flick of the sheet or traveler line takes it out of its cam cleat, and a downward tug locks it back in. The lines rest within reach beside the companionway. (A tiller is pretty much mandatory to get helm position forward.) The only minor annoyance is sheeting in close-hauled, when I have to get up and put a foot above the companionway for leverage. Regarding vang/sheet hybrid action... true only when the boom is too high or traveler too low, and I seldom see sailors taking full advantage of their traveler, which would be when the car is at its windward limit and the boom is over the lee quarter or beyond.

Posted by: Jack Schmidt | January 19, 2018 12:11 AM    Report this comment

As long as you have the boom height clearance, the addition of an arch over the cockpit will give you boom-end sheeting and allow you to add a traveller, with a slight sail re-cut to raise the boom if needed. The arch needs to be substantial to take the loads. Added benefits include giving attachment points for a bimini, solar panels, etc. I see many off-shore boats that have added an arch for power and protection and stop short of moving the mid-boom sheeting, which I find strange given the articles points. See any Hunter to get the idea.

Posted by: DaddyO | January 15, 2018 8:46 AM    Report this comment

In regards to jibing the Chinese Junk... To the extent possible, sheet the main in to the boat's center before the jibe. I do this as standard practice on any/all sailboats - prevents the sail from slamming over and potentially breaking something. No loud BANG either

Posted by: PJ | January 15, 2018 8:35 AM    Report this comment

I too like the end-boom sheeting on our old 1972 Irwin 32 with tiller steering I can easily single hand this boat except when using the chute. Yes I might have to go to the mast to adjust my boomvang which is seldom done and if I want to I hook on the auto pilot for a couple of minutes. My traveler sits on the rear deck in front of the lazerette and I can adjust my foot and leech by standing up and reaching the end of the boom.
Bottom line all are easily reachable and without any effort from my 7' cockpit without big steering wheels to get around.

Posted by: EJO | January 15, 2018 7:00 AM    Report this comment

My first boat was a Catalina 30. My current boat is a Beneteau 321. Both have mid-boom sheeting. I do much much more racing than I contemplated when I bought these boats. End-boom sheeting will be high on my list of desirable features in my next boat, for all of the reasons in this article. Useful article.

Posted by: mark2 | January 12, 2018 12:50 PM    Report this comment

smerrick, I have a tiller steered Pearson 28 with the main sheet traveler over the companion way hatch. I single hand all of the time. Cleating and uncleating the mainsheet is not a problem. I just ensure the main sheet itself is always within my reach. But like I say, the actual cleating and uncleating is quite simple even from the aft portion of the cockpit.

Posted by: Captain Bob | January 12, 2018 7:58 AM    Report this comment

I have been looking at a Catalina Capri 26 which has a 9' cockpit and the traveler above the hatch for mid boom sheeting. Been trying to visualize how you singlehand this boat, seems you would be too far away to get the mainsheet to release or catch. Also with passengers it would seem you could catch someone around the neck if they tried to switch sides at the wrong moment. Anybody got experience with a setup like this? Maybe im missing something.

Posted by: smerrick | January 11, 2018 8:28 PM    Report this comment

I have end boom sheeting in the cockpit on a Morgan 382 and I would not have it otherwise, even though it restricts bimini size. (1) The sheet is easily available when single handing. (2) The leverage is improved so I can bring in the mainsail without a winch. (3). The sail control is better and I can shape the sail more with a vang. (4) The stress on the boom is less. the only improvement I have seen from this traditional approach are the modern boats that have end boom sheeting attached to an arch, so the sheet does not get in the way of relaxing in the cockpit.

Posted by: terrythatcher | January 11, 2018 6:31 PM    Report this comment

I wish it were that simple on my 1900 HoSang Chinese Junk. I've racked my brain for years trying to solve this problem. Since a jibe is a standard maneuver on a junk, my mainsheet leads to the aft arch over the large gong at the stern. Unfortunately, when you jibe, you really need someone taking up the sheet as fast as possible so it doesn't behead anyone in the cockpit when it drags across. I would love a suggestion to solve this problem.

Posted by: Mandarin Star | January 11, 2018 6:06 PM    Report this comment

Good article. I learned why there are multiple blocks mid-boom leading back to the mainsheet traveler on my Beneteau 393. They are to spread "fulcrum-like bending load linked to the mid-boom attachment of a mainsheet".

Posted by: Dan C | January 11, 2018 3:49 PM    Report this comment

Very interesting article. Minor typo, it is "...farther forward" not further when it comes to distance on the boom. We have Beneteau First 22's and we moved the mainsheet block from the cockpit sole to the transom to get the mainsheet out of most of the cockpit. If it was placed on the cabin, the skipper on the tiller would be too far away to adjust the mainsheet. Obviously not a solution on every boat, but another option.

Posted by: Parker | January 11, 2018 9:48 AM    Report this comment

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