Sunfish ‘Snow’boat?

Thread starter #1
The bay I sail on freezes in the winter. The surface however never completely clears of snow. The lake that feeds the bay also changes levels - developing layers of ice. Simply, we don’t get good ice. I wanted to create ‘snowboat’ (not sure if thats a word :confused:) that uses runners that ride on top of the snow, instead of blade-like runners that cut through the ice. The boat is based around my Sunfish rig.

The steering runner is misleading in the picture. This ski will be a lot shorter to decrease the torque required to turn. Other things that aren’t in CAD are the fore and side stay, and the main sheet path.

The steering mechanism is reversed in the drawing, but I think I can fix that easily by changing the push-rods to cables, and cross them.

Has anybody built a snowboat before? Have any ideas what the runners should be made of?
 

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Thread starter #2
Oh, a few other things:

In working out the geometry, I found that tilting the mast back slightly allows a more evenly distributed stay orientation. The tilted mast also causes the boom to swing up when running downwind, allowing more room between the side stay. Also, the side stats will not be rigid, they will have some slack to let the sail and mast fall leeward - this again plays in favor of running downwind.

Take in account that I don’t expect the first try to be perfect, and in no way am I setting the sunfish rigged speed record :D.

Thanks for any input or advice!
 

thieuster

Active Member
#3
The second half of the 16th and first part of the 17th Century were very cold in Europe. Some speak about a 'small ice-age'. On Jan 27, 1600 (!) Dutch merchant and inventor Adriaen Terrier (pronounced like the word 'Venier' in 'Venier Caliper') filed a patent request at the 'Staten' (something like the US Senate nowadays) for a 'ship on irons with a jib and mainsail for the transport of people and goods over frozen lakes'. He soon found out that the ships were able to reach unbelievable speeds! Something he hadn't thought of... Later, Dutch settlers took their small ice sailing vessels to the new world, mainly the NE part of the USA, Michigan and Canada. It was the Detroit News in 1937 who came up with a competition for a new model: the DN. When you search the internet, you must be able to find a lot of blue prints and ideas for the perfect ice sailer.

Ice sailing was very very popular here in the Netherlands up until the second World War. After the war, industrial activities and changed the temp of the water during the winter; it has been a while since all lakes were frozen up for serious ice sailing competition. (1997). Dutch sailors tend to travel to the Baltic countries, Finland and Sweden for ice sailing races.

Here's a nice pic of a replica of Terrier's design and a DN on the Kaagerplassen (Lake Kaag), about 15mins from Schiphol/Amsterdam

 
Thread starter #5
I’ll post some updated pictures of the CAD soon. Until then, does anybody have dimensions, or at least the location relative to the lower boom of the ‘swivel boom blocks’? I can’t seem to find that information.
 
Thread starter #9
Ah yes :D ‘Cheapskate’. Very curious if that same rig sails well in snow (which I heard is the equivalent of sailing a yacht with the keel turned 90 degrees :confused:).

064D61FA-1C4E-47DC-8FE4-AAFF676BE539.jpeg
 
Thread starter #10
Why are iceboat runners VERY heavy? (At least the old ones). I’ve seen them made of cast iron, 1/2 inch thick :confused:. Is this the equivalent of a weighted keel?
 
Thread starter #11
I’m guessing the runners I saw came from a stern-steering design — where the cantilevered runner would act as a ballast.

Any ideas on a cheap runner? I’ve seen angle iron (even bedframe :eek:), steel sheet (which I suppose is the best method, at a thick enough gauge and given a “V” edge), I’ve also seen “T” stock used.

Season is almost over for us, but I would like to finish a descent set of runners before I pack it up.

(Picture for looks, not practicality just yet :cool:... yes, I know the sail is too high and the ski in the front was only a temporary experiment)
 

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