an ice boat sail question

[Jim Budde]

I have a little Skimmer; a great little toy made of tubular steel, three runners, a canvas sling seat and an old un-battened sail of questionable origin. . For those of you who have never sailed hard water you don't know what you are missing. (But I digress). I also have some relatively new sail material in the shop and my friend has ability to duplicate and sew a new sail.

Here's the question: would I gain any significant speed by flattening the current sail's design and adding full battens like the DN Class? Not interested in philosphical discussion of sail making .. just quick and dirty suggestions because iceboat season in Nebraska doesn't last very long.

Thanks in advance
Jim

[Dan McCosh]

Might pick up a little speed, but realistically, the Skimmer doesn't have the compliance or the width to get up to a serious speed. Iceboat sales are virtually flat, and a slight shape is sometimes created with tensioned battens. The mast usually is rotating, and it's flat shape creates part of the aerodynamic curve of the sail. I don't remember the Skimmer as having a rotating mast. Bottom line is that a flat sail would probably work just fine.

[Todd Bradshaw]

Having done just that to my old Skimmer, I would say that you can certainly pick up some general performance, as well as some speed, but speed on a Skimmer is limited by the hull, not the sail. At around 40-45 m.p.h. the foot steering on a Skimmer gets REALLY touchy. The lack of any sort of suspension just makes this worse if you have any rough ice to cross, as it's difficult to steer smoothly with your feet when they are rapidly getting bounced around.

The mast on a Skimmer has a bump on its bottom end which sits in a dent formed in the steel plate mast step. The shrouds and headstay connect to one point on the upper mast's front, so the mast is free to rotate pretty well. What I did was to add some roach up high on the new sail (maybe an additional 5 sq. ft. or so) and I switched the top two battens to full battens to support the roach. Battens were ash, about 1/4" thick by 1.5" and tapered in thickness to about 1/8" up front. At the luff, the sail had heavy leather pockets sewn over the Dacron batten pocket sleeves to keep the battens from punching through. The aft ends of the batten sleeves had small grommets for the batten ties. On a sleeved luff which slides over the mast, trying to pre-tension full battens doesn't work very well. It tends to force the batten forward against (or beyond) the mast. For this reason, you are better off to maintain your airfoil shape by adjusting batten thickness and the bending characteristics of the battens than by trying to use compression and pre-bend them. Tie them in tight enough to stay in place, but there is usually little to gain with that type of luff by trying to pre-tension them. You could use a full batten in the lower position as well as the upper two, but since you aren't adding roach down there, it really isn't needed.

I cut the sail with about 3/4" of luff curve, no significant luff broadseaming and a couple of very slight (1/8") leech broadseams, just to help keep the leech tight and flutter-free. Batten pockets were formed by making upper panel overlaps about 2.5" wide with open centers to slide the battens in.

Is it worth the extra work to make a new sail? Probably, as long as you enjoy the project, and a little more area up high seemed to improve light air performance. Is it going to be a night and day difference? Not likely.

The first thing I would do on a Skimmer is to have somebody weld a small extension plate about 3"-4" square to the back of the mast step plate. Then you drill a few holes in the new plate and mount a small swivel rachet block (no cleat, just the rachet) there for the mainsheet. Mainsheet tension is no longer trying to lift you out of the seat, it's pushing you down into it and the rachet reduces the amount of tension you're hand-holding. The boat doesn't go any faster due to this change, but it's a lot more pleasant to sail and it's well worth the cost of the modification.

Have fun! Despite its simplicity and limitations, the Skimmer really is a great little iceboat and a blast to sail. I sold mine for $500 when we got our Arrow about seven years ago and I'm still kicking myself for not hanging-on to it.

[Jim Budde]

Thanks, guys. I will go ahead with sail modifications and , since my shop s equipted w/ welding capabilities, I will do modifications as suggested.

Todd .. I bought my Skimmer for $150 two springs ago. Last winter we had 20 - 24 inches of ice and limited snow, so a great first season. GPS gave me a 28 max speed, but more important was hours on the ice .... what a rush! Ice toady is anywhere from 8" to 11" with a few snow drifts, but certainly enough for fun.

Thanks again. Will post pictures if someone is around to take them next weekend

Jim

[Todd Bradshaw]

One thing I considered on mine and never got around to was building a reduced-size storm sail for days when it was really blowing and control was getting a little squirrelly. In some places, it might be a more valuable addition than a bigger, battened sail. I did sew another panel of fabric to the underside of the seat and stuck a hunk of closed-cell foam (cut from an ensolite backpacker's sleeping pad) in there, which provided some insulation to make the seat warmer - which was nice.

We have a lot of world-class iceboats in our area and it was a little bit intimidating at first to show up at the ramp with the Skimmer and be surrounded by all these incredible racing machines, but in may ways, it's a nearly perfect little recreational boat. You can be assembled and out sailing in less time than it takes the big guys to even get their trailers rolled out on the ice, storage space is minimal during the off season and you don't have much money tied up in the project. Since the current DNs have pretty much evolved into all-out racing boats, it might be worth trying to design a simple, small, Skimmer-like boat as a wooden home-built.