Iceboat design questions

[JOBBER]

I read some old threads here on iceboats and have some questions on smaller ones; 3-4 meters. It appears there are two types of design; either front or rear steering and the cross board opposite respectively. How would the performance, maneuverability, and ride comfort differ in each type? The operator would be 220+ lbs.

[paladin]

220 pounds....steer with front, sit on crossmember on rear....depending on where you run it wear heavy protective "road rash" gear.....I never ran one on ice...but have built several to designs in Pop Mechanics and put wheels on them....and they will go faster than you need to go.....

[Capt Nat]

All well built iceboats are fast...no iceboat is comfortable. The DN offers the most performance relative to cost.

http://www.neiya.us/specs/dn60.html

The Four Lakes Ice Yacht Club (Madison, WI) is one of the largest and most active clubs in the USA. If you're seriously interested in iceboating, contacting someone within that club will be well worth your while. Below is a link to the club website...other designs are explained there...

http://www.iceboat.org/faqiceboat.html

[Todd Bradshaw]

My iceboat is actually quite comfortable - aside from the obvious cold weather and wind chill. We sit, side by side, in a carpeted well with a seat cushion/back-rest and the boom is at a height where ducking your head for tacking is about all it takes.

http://webpages.charter.net/tbradshaw/arrow-006.jpg

The Four Lakes club is very active, but also very race-oriented. They race DNs, Renegades, Nites and Skeeters, but have no real interest in touring boats or home-builts, so you're not likely to get much helpful information out of them for your purposes, but there are always some good photos and links on their website.

Unless you want to go big (20' long or better) a bow-steering boat is probably going to be your best bet. They can be built small and light, car-topable with quick assembly. The older DNs were reasonably comfortable, but modern racing DNs have lost much of that because they've lowered the rig so much. They currently sail prone with the boom all the way down on your shoulder and some of these sailors even have bungie cords attached to their helmets to keep their heads up.

I'd start with a book search. "Think Ice" is an old book put out about DNs and worth reading if you can find a copy. The DN class association (The IDNYRA) used to sell it. but I can't get their website to open at the moment (IDNYRA.org). It has a lot of good info and was written before the boats got so extreme. Another good one is a very old book called "Wings on The Ice" that some public libraries can get hold of, especially if they have an inter-library loan system in place.

For a minimalist approach, take a look at the "Skimmer 45" iceboat.
http://www.skimmer45.com/
It's a bunch of welded tubing and a sling seat, but could be duplicated after a fashion in wood. It's so small that it looks silly, but they're quite fun to sail and we used to be able to get ours up to 45 mph or so before the foot-steering got really touchy. The "Ice Opti" is another good one to check out.
http://www.iceboat.org/optis/links.html

For hardware, try:
http://www.sarnshardware.com/About.html

Design-wise, the larger the platform (spread between the three runners) the more stable the boat is and you generally want your runner plank pretty much directly below your sail's center of effort. Then it's a matter of getting your crew weight spread over all three runners so that you have both some grip for steering and you avoid the runners on the plank slipping sideways (which is seriously no fun and pretty scary).

Some designs, like the "Ice Flyer" and a few of the big fancy Skeeters actually have the sail behind the sailor. I've been threatening to build a little one for a while that would be basically a reinforced, thin plywood and bulkheads box with a runner plank and a springboard out front to try this up-front style of seating, but haven't gotten around to building one yet. With nothing out in front of you except the springboard, the view at speed would be pretty interesting.

http://webpages.charter.net/tbradshaw/BB%20ice.jpg

[Capt Nat]

Todd, I thoroughly enjoyed your music samples. In the photo of the band, do names line-up vertically with members?

About the comfort of iceboats...40+ years ago any and all iceboats had some degree of comfort, but now my idea of comfort is...
http://www.kadeykrogen.com/39/gallery/photos/39-1.jpg...somewhere south of 30˚ N latitude between December 1st and May 1st!

[Daniel Noyes]

here's the third type, no steering runner it steers with the sails.
http://www.youtube.com/watch?v=afXlrW-T61Q&feature=channel_page
and here is a ride where the camera man (me) gets thrown off
http://www.youtube.com/watch?v=urWxjjeNwCU&feature=channel_page
Dan
http://dansdories.googlepages.com

[JOBBER]

I tried the Google search this time, and found enough information to keep me busy for awhile. Mr Bradshaw thank you for ALL your previous posts on iceboats. I hope I am not causing any offense or breaking any rules by "copying" most of your past comments and placing them in a Word document. I just wanted to organize them by topic to make reading easier.
Again - thank you.

[Dan McCosh]

I read some old threads here on iceboats and have some questions on smaller ones; 3-4 meters. It appears there are two types of design; either front or rear steering and the cross board opposite respectively. How would the performance, maneuverability, and ride comfort differ in each type? The operator would be 220+ lbs.

Older designs (1930s or so) had a long timber down the center, a runner plank up front and steered with a tiller and a single runner at the rear. They were prone to ground-looping when the rear runner broke loose. The front steering provided a better balance under the high lateral loads you get. One drawback is you get higher in the air when flipping over. The flexibility of the runner plank can affect the ride, but mainly it is as rough as the ice you are on. The DN (Detroit News) is the most popular class today--once was a popular homemade design, and now comes in high-tech materials.

[Todd Bradshaw]

Between Google and all the YouTube iceboat videos, you can keep busy for a long time. I thought this was a neat illustration.
http://image18.webshots.com/19/4/76/12/211447612QhAaTf_ph.jpg

Captain, yes. the names line up pretty much with that first photo. Most of the other photos on the site and those in the bios are also labeled.

[JOBBER]

Question on runner plank spring and runners.
Picture below is normal bow-steer iceboat.
http://i283.photobucket.com/albums/kk313/JOBBER48/SPRING.jpg?t=1245025503
When constructed and no load the runners are perpendicular to ice. When occupied the runner plank bows and the tops of runners are pulled in. Sketches below show both conditions.
http://i283.photobucket.com/albums/kk313/JOBBER48/blade.jpg?t=1245025804
My question is would the chisel shape work better for the rear runners? It would appear the 45 degree shape (when dug into the ice) is running more on "flat" than edge.

[Todd Bradshaw]

Actually, it's a competition DN, which is normal for racing, but a bit on the extreme side for recreational sailing. Most touring boats have planks that are a bit stiffer. Over the years, everything possible seems to have been tried, from stiff trussed planks that didn't bend (the old Madison-style) to some of the super springy planks currently used for racing (some of them nearly touch the ice at times when hard-pressed). Most of the folks I know build their planks with some crown and reinforce or thin them so that when they're sitting in their boat, the plank is more or less straight. There is a lot of down-force on the plank while sailing and that seems to be the best general compromise, offering good shock absorbancy and keeping the runners on the ice.

I'm pretty sure that just about everybody around here sharpens their runners to a 45 degree angle. Some of these guys build incredible custom runners that are worth $1,500 or more per set of three, and I don't remember seeing any unusual angles. They are, however, extremely picky about how they sharpen them and the quality of the final edge. They also go to great lengths to make sure that their plank runners are straight with perfectly parallel edges. If they aren't straight, you can actually hear and feel the difference. They will make a little "skitching" sound every few yards as one of them strays slightly from a straight course and is forced back into alignment by the plank and chocks. That costs you speed every time it happens.

The 45 degree V-shape also allows you to sharpen all six sides of your runner edges on the same jig and get the proper angle on all of them. From what I can tell, that method seems to be all that's needed to go much faster that you would ever want to crash at. What more could you ask for........?

[JOBBER]

I ordered and received my iceboat plans. They fit my abilities and budget - both minimal. The iceboat seems a variation of the Frostfish or Isabella. I have included the website, because of a large amount of free (basically defines the valve) information.
http://www.cherrywoodmedia.com/Plans/IceBoat/iceboat.htm (http://www.cherrywoodmedia.com/Plans/IceBoat/iceboat.htm)
The main reason I chose them was their recommendation for the sail for the craft. Their FAQ section even has a vendor for replacement a Snark lanteen rig. You can purchase a mast, spars, and nylon sail very reasonably. For a modest fee an upgrade to Dacron (unspecified weight) is available. I would think you would want 1/4"?

After reading the large amount of related material here on the WB Forum, I came to discover:
"...People have had plenty of fun sailing home-made iceboatswith old Sunfish rigs on them, but an afternoon's sailing can pretty much trash such a light sail. The more normal starting point for iceboat sailcloth would be 8-9 oz. fabric or heavier..." Todd Bradshaw

Finally after reading my plans, I discovered the most of the fasteners were 5/16" bolts, with the ones for the runners grade 8. This struck me as strange, because the "metal" hardware components were fabricated from 1/8" thick plate or angle stock. This included the runners, 10ga SS with angle stiffeners.

Until I resolve the sail issue things are on hold. Thanks again for all the historical and current replies.

[Jim Budde]

For what it's worth , I bought the plans (from a friend who did not build the boat) and built the ice boat you intend to build ... the following winter I bought a used Skimmer for $150 bucks and never looked back. Unlike soft water sailing, the joy of hard water adventure is not in the building .. it's being on the ice. I strongly recommend you find a used Skimmer and give it a try before spending the time and money building your own ... and by the way, the sling you will sit in is quite comfortable and when you flip her over at 40mph you will not have very far to fall : ).

Only modification I made to the old girl was an aluminum mast .. much easier to step in a blow than the heavy steel mast that comes with the Skimmer. I just keep her in the van and whenever wind and ice are a go ... I go. My DN friends go faster, but they also take longer to set up than I do ... and they must plan ahead. It takes about 15 minutes from the time I back the van up to the ice till I am off and sailing .. the boat you plan to build takes a lot longer to set up, is a lot heavier (does not fit in the back of a mini van) and will not go nearly as fast

[Todd Bradshaw]

I still kick myself for selling my Skimmer when we got the Arrow. I let it go for something like $450, which was really dumb. Granted, the Arrow is much more sophisticated, a lot faster and holds two comfortably (although my wife and I did sail the Skimmer a couple of times together and it was cozy, but worked decently), but the Skimmer is in the category of "nearly instant fun" and we could always put in two or three runs while everybody else was still back at the ramp, putting their boats together. I'm surprised your Skimmer has a steel mast. Mine was an old one with a two-piece aluminum mast. Maybe a previous owner upgraded it, but it looked original in terms of how everything fit together.

Jobber, whatever the upgrade price is for a Dacron sail, it's worth it. Nylon is too stretchy to make a decent iceboat sail. The Dacron will likely be in the 3.8 oz.-4.2 oz. range, depending on who they buy fabric from. It's still awfully light for the loads that iceboat sails get, but should be much better than nylon. The cut will also be a bit too full, but the yard and boom should bend enough under the high mainsheet loads of an iceboat to eat up nearly all of the luff-and-foot-curve-induced draft and it should flatten out reasonably well at speed. The first sign of fatigue will likely be a lot of leech flutter. If that happens, you can always have somebody re-cut the leech to a curve with a deeper hollow, which should help and is pretty simple to do.

For what its worth, these are the changes I would make if I was building an Ice Tender. I would upgrade the thickness of the runners to something closer to 3/16"-1/4". In use they are under tremendous strain and they need to stay straight to be efficient. It just doesn't make sense to use 1/8" plate for runners. I would also consider using thicker angle for the chocks on the runner plank and the steering runner chocks. It's important that these are strong and keep the runners straight. Runners or chocks deforming in use is not an option if you want your boat to work well and be safe. My Skimmer had 1/8" plate for the chocks and I used to have to go out every once in a while and bend them back to the proper straight configuration.

I would also REALLY like to see a little bit of a floor of some sort right under the foot pedals (maybe a plank, a bit of stretched netting, etc.). The reason is that when you hit a rough patch of ice at speed, it's sometimes possible for one foot to slide off the pedals. The boat immediately makes a very sharp, full-speed turn and the heel of your loose foot hits the ice. The unplanned turn is somwhat dangerous and if your heel hits a bump in the rough ice at speed, it could easily break your leg. It would be very nice to have some small addition there that would prevent this from happening and stop your foot before it can contact the ice. You will find that like all little foot-steerers, the faster the boat goes, the more touchy the steering gets. At high speeds, you have more important things to worry about than dropping a foot off of a pedal.

Finally, make sure your sailing pants seal well along the bottom. Exposed as they are on boats like these, open cuffs make for a whole new definition of "wind chill". :)