Small Boats with Full-batten Mainsails Have Few Options for Reducing Luff-slide Friction

Posted by Darrell Nicholson at 10:31AM - Comments: (2)

A small wire retains the bearings on the Harken luff slides. Boatbuilders say the wire bends easily allowing bearings to escape.

One of the key improvements made to the mainsail featured in the August 2011 article on choosing a mainsail was the addition of the Tides Marine Sail Track, a slippery track made of ultra-high molecular weight plastic that can be installed onto an existing mast track.

Another option is to install one of the various rolling, low-friction batten slides on the market. Harken, Rutgerson, Selden, and others make slides designed to handle the high loads imposed by a roachy, full-batten mainsail on the mast, but these are generally more expensive than the Tides Marine option.

One of the difficult challenges faced by these slides are the side loads imposed when the sail is not feathered into the wind. In the event that the sail needs to be dropped (or raised) off the wind, the unequal loading on the batten cars can cause friction on one side or the other of the cars.

Harkenís bearing slides pictured here are one approach to solving the friction problem. While some boat manufacturers have had good results with these slides on larger models, the trend toward trailerable, user-friendly boats presents a problem for these types of bearing slides. As we found in our recent boat tests of the Presto 30 and the Norseboat 21.5, the Harken slides are problematic for smaller boats that remove their sails for trailering.

According to the makers of the Norseboat 21.5 and the Presto 30, the retaining wire that keeps the bearings in place is thin and tends to bend, and once bent, they are nearly impossible to get back into shape. On the Presto 30 we tested, the owner had given up chasing bearings around his deck and was using the slides without the bearings, making raising the sail a bearóso to speak.

We spoke with Harken about this, and they said they were aware of the problem with the retaining wire, but that because of the small size of the slides, there is no easy solution. Harken says there is very little demand for bearing slides in this size. The problem does not exist in the bigger sizes, according to Harken. If you donít remove your sail for trailering, you may never run into the problem. The Presto and the Norseboat, both of which tout their relative ease of trailering, are opting for Strong Tracks in their future boats.

Comments (2)

This begs the question of why the full batten sail in the first place? Our contention is that for the most part fully battened sails are grossly over-hyped and inappropriately recommended. Most conventionally rigged boats cannot take advantage of the additional roach that can be provided by a fully battened main. For that, you need a boat without a backstay or be prepared to deal with a lot of chafe along the leech.

For most boats with a backstay we generally recommend the top one (sometimes two) battens full, and rest partial. When I say partial, I'm not referring to a short leech battens like the old days. Our partial battens are a little longer than 50% of chord to preclude what I refer to as "hinge effect" wear.

With a fully battened sail you actually give up some of the control over sail shaping to the battens. This means you can't easily change the shape of the sail to suit the conditions.

If you are overpowered with too large a headsail you can't depower a fully battened main the way you can one with conventional battens.

Cruisers suffer from a lot more chafe with fully battened mains than one with partial battens as described above. We've seen the results when people make the crossing from the west coast of North America to the Marquesas time and time again.

I keep hearing stories about how fully battened sails work better with lazy jacks than partial batten sails. However I've never really seen it for myself if the lazy jacks were properly designed and installed.

Full batten mains add lots of weight and friction. All that translates into the need for a track system. Voila, we have a solution in search of a problem.

Full batten sails are great for sailmakers and the manufacturers of track systems and battens. I get requests for full batten mains from people with boats as small as 20'. We send everyone an article to read about the pros and cons of fully battened sails. I think about 70% change their mind and go with a partial full batten main.

We are happy to build full batten mains and sell track systems. It just puts us that much closer to retirement and full time cruising so don't let me discourage you too much!

Our philosophy is we should always recommend what we would put on the boat if it was our money. I think our customers appreciate that.

Dave Benjamin

Island Planet Sails

Posted by: DAVID B | August 7, 2011 8:40 PM    Report this comment

The friction problem with many small boat mainsails is greatly aggravated by the track style on the mast. Tracks that take a barrel shaped slide are the worst for jamming. These tracks are actually designed to take a bolt rope and not slides but have become ubiquitous on smaller spars. I find that the best, and least expensive solution is to use all plastic slides and plenty of dry teflon lubricant. Bainbridge sells a very strong, slippery slide called an Allslip slide, #A118 for 1/2" groove. We use these at the front of the full battens. Between the battens, on mainsails about 150sqft or less, we will use the Bainbridge #A018 slides. In any case, plenty of dry teflon lube will help.
Aaron Jasper, Jasper & Bailey Sailmakers

Posted by: Aaron J | August 6, 2011 10:59 AM    Report this comment

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