SAVO sledge – easy surfing on ice and snow

Surfing in winter is easy, in fact easier than summer windsurfing upon water. You can use same old rig (although 8.5 m2 is largest sensible sail size). The only thing missing below the rig is a sledge. SAVO is a “Copy-Cat”, very close by its dimensions and idea to legendary Black Cat sledge developed by Arto Ravander in Finland. SAVO is not fastest (Black Cats seem to be faster, although in WISSA 2008 all track courses were won on SAVO sledges) and there are also easier sledge constructions – but nevertheless, it is a very efficient compromise, sort of SUV. Skate sledges are faster on ice, wider and larger sledge can be easier for the

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beginners and all adjustments are not always necessary, but why? This sledge can go almost anywhere – ice, hard packed snow, powder; lake, sea, field or coastline… It is easy to build and you can always transport one

deck, two pairs of skis and two sails on the roof of you car to any place you like.

I put some instructions down below. You don’t have to follow everything literally, but it has worked well for me.

1. Skis

Unless you are willing to make your own skis you should find somewhere one pair of speed skis (about 240 cm of length) and one or two pairs of ski jumping skis (250-260 cm). If you are a beginner any old steel edged skis would do – the longer, the better and preferably as straight as possible. However with short skis the sledge will start skidding sideways, wobble at higher speeds and more than 5 cm of soft snow will be an obstacle.

Speed skis shall be used always when it is slippery – on dark steel ice or white ice patches upon hard snow. Steel edged skis have to be turned more on their edges and that makes them to drawn in the snow easier. Besides they are quite stiff and will bite right into the snow pile instead of gliding on it. There is also a problem of bottom plastic “boiling off” on dry uneven ice.

Ski jumping skis are light, wide and very, very flexible -almost optimal for this sport, but lack of steel edges prevents driving on icy surface. Medal has always two sides; snow dunes are very funny with them! One can add “spoilers” to the rear part of the skis, vertical surfaces preventing rear edges from biting into soft snow and skidding sideways.

Any skis should be waxed properly, otherwise their will not be sliding and upwind sailing will become difficult. If plastic at the bottom is badly scratched it should be grinded at a ski shop. Different grinding is used for different temperatures and moisture conditions. After the grinding the skis shall be waxed with soft paraffin base, thereafter with graphite wax. After the waxing all excessive wax shall be scratched away and surface brushed. Graphite is a good protection, but thereafter wax suited for given temperature and moisture shall be applied. There is no need to remove old wax by any liquids, good brushing is enough. Expensive Fluor-based waxes and powders shall be used only if you are seeking for maximum speeds at wet snow.

2.jpgGuessing snow conditions in advance can be difficult, especially if sailing location is remote and whether can change. Therefore it makes sense to prepare three pairs of skis. Use steel edges if surface is icy (for instance water froze after the cold night), on soft snow you may want to use two different pairs with different waxes (cold vs. warm and dry vs. wet). Changing other pair of skis to you SAVO will take only few minutes.

2. Deck

Deck is easy to make from few pieces of plywood, although glass fibre or aluminium are also OK. Do not make it too heavy or rigid. It is good enough it takes normal driving and first ten crashes. If deck is stiffer that the skis all forces will be bending the skis and vice versa. If both skis and deck are stiff you will end up riding “break your teeth” stone mobile.

If you are laminating plywood you should make a mould – solid wood is better, but few 2×4’’ planks cut into shape would do as well.3.jpg

Put 40×135 cm plywood pieces, softened by steam or hot water, on top of mould with enough of white polyvenylascetate-glue in between. Try to get “aeroplane-plywood”, very flexible, 1.5-2.0 mm thick pieces. If not available, use normal 3-4 mm birch plywood. Unfortunately less than 10 mm laminate will not last the crashes, go for 12 mm. Thicker than that will be too stiff in my opinion. Plywood pieces with glue shall be tightened to the mould either by press or by screws (screw holes will look ugly, but have no effect on driveability, it is much more important that there is no air in between and deck is evenly glued). Hinge area can be strengthened by some glass fibre textile with epoxy glue – this will be the weakest spot of your sledge. 2 mm aluminium plate can be glued under the mast blade in order to keep mast joint attached even in bad jumps or crashes.

After one day of drying take the deck out from press, draw a centre line and shape of edges and cut it with electrical jigsaw. This is also good time to make holes for the hinges, pay attention that distance is exact (400 mm and dimension cross check). Holes for the mast blade shall be done with 30-50 mm interval. Picture below does not show proper cut of rear hinge holes – they shall be large enough for you to operate adjustment keys.

4.jpgNext step is to glue anti-slip rubber pieces (black grooved rubber for instance) – picture above gives an indication of proper places. Once glued, rubber patches shall be protected by tape/paper.
If you do not want your deck to absorb moisture it shall be painted with a spray coat. First there is a base (approximately one can), then main colour, for instance harder steel rim colour and a contrast colour. If you want you SAVO to look right, use heraldic black and gold scheme. After the painting apply couple of layers of lacquer.

There are at least two ways of making the footstraps. Old school uses permanently fixed pieces of transmission belt or similar. Rear strap is single long one – you can slide you foot along it either to front or to rear end. My own approach is to use standard summer board footstraps placed as in the picture. Sure enough the rubber patches shall be near the foot straps. Front straps affect steering quite a loot – if they are too much behind turning downwind will be difficult, excessive front position makes the sledge insensitive and bad on upwind angles.

You will have to think about proper “breaking order” for your deck. Footstraps are the first ones to tear off if you crash badly, then you can break hinge and mastfoot area and only after that your own ankles and other body parts.

3. Hinges

Simple way to attach skis to a deck is using of bended aluminium or steel pieces or plastic pieces cut into shape. Suitable tilting angle for snow is 20-30º and 30-45º for the ice. Fixed connection is very good for the beginning, but when your skills improve and speeds grow up skidding or biting into the snow will start to irritate – you will want to go 10 km/h faster instead.

This hinge is an easy way of angle adjustments, I will put exact dimension drawings separately.5.jpg

It consists of two plates, lower one of them has two loops welded to it. One of the loops holds a fixed rod (pointing forward, so that even in case of breakage the ski will not fall off and one can sail to the starting point where all the tools are). Second loop holds Allen screw tightening another screw pointing upwards and adjusting the tilting angle. Adjustment screw is fixed to the upper plate by nuts and washers. If using M10 screws it is enough to sail with 19 mm key and one L-shaped Allen key in your pocket.

Tilting adjustment is done at the rear hinges, front ones remain free. It is a good idea to carry one spare set of screws in a pocket. If there’s a break down one can fix temporary adjustment to the front hinge too.

Stainless steel (AISI304/316) is perhaps best material, but normal carbon steel is OK if painted afterwards.
When making the hinges one should make one set of upper parts and as many lower part sets as there are skis available. When each ski has its own lower part change operation will take only few minutes.

Steel edged skis tend to have metal upper surface as well, but modern jumping skis have thin layer of plastic with honeycomb structure under it. Hinge screws will not stay there unless you’ll glue 2 mm aluminium plates between them and the skis with epoxy or similar glue. Aluminium plate is an excellent holder for 4-5 mm screws, even short ones.

4. Adjustment

When all bits and pieces are ready one should put them together properly.

6.jpgDistance between the hinges is 400 mm. Deck’s rear edge comes 250-400 mm from the rear edge of the skis, more at the rear if using jumping skis on snow and a bit further if there are steel skis for the ice (deck at the rear => front part of the skis is loose and comes easier on snow dunes; deck at front => rear end has better side grip and one can go for higher speeds).

Mast shall be adjustable few centimetres backwards and forwards for different wind speeds and sail sizes (unlike in Summer, bigger sails require mast at the back for better upwind performance) – it is enough to have 3-4 8 mm holes with interval of 3-5 cm.

The skis shall open forward ca 20 mm (outer edges measured at front ca 20 mm wider than at the rear) without load at the deck – in practice it means that skis are in parallel when there’s sailor’s full weight at the deck. Wider opening allows easier handling, parallel skis are faster, negative opening acts as a brake. Correct setting is between 10 and 40 mm. SAVO does not have adjustment for the opening, therefore the skis must be properly set when fixed. Easy way to do it is fix the rear hinges first and then position front hinges with double sided glue tape and marker. Once the opening is correct, disassemble rear hinges from the deck and fix the front hinges to the skis. Thereafter have a check – did you do it right? 

Footstraps shall be adjusted to fit the winter shoes. In the dune jumps your foot will not stay in a loose strap, but if you crash down, you should be able to get yourself out easily…

5. Sailing Technique

Having built everything you could start sailing. Temperature shall be between -10 and +10ºC. Minimum wind speed is 3 m/s, anything above 10 m/s can be dangerous. Sure enough ice should be thick enough. Mind stones and standing ice blocks – you may not see them because of the snow! One should have a compass or GPS if sailing in blizzard, even on familiar waters (very easy to get disoriented!) and somebody should know where did you go sailing and did you come back safely

For safety’s sake one should always wear a helmet and strongly recommend to use back, knee, elbow and shoulder protectors as well. Textile made motorbike suit with inbuilt protectors works really fine. Do not put too warm underwear – it will be hot! Take some large sized gear you can put on top of your suit instead – you may want to use it if staying in one place for longer time.

Starting direction is perpendicular to the wind, back towards it, boom pointing same way as the wind blows. At first rear end of the sail is hauled closer, as soon as sledge starts moving front arm is extended straight preventing sledge from turning against the wind. Steering is done by tilting the sail back and forth, at higher speed also the sledge shall be tilted – same side as the turn goes. It is possible to make downwind turn (slow jibe) with radius of 10-20 meters on soft snow, more on ice. Turning against the wind requires full stop of the sledge – nose upwind, feet down, sledge up, turn the sledge and start in opposite direction (when done properly, turn against the wind takes only few seconds and is in fact faster than any jibe).

In comparison with summer surfing sailing position is more upwards, feet are close to each others. Upwind angle exceeds best of the daggerboards. Top speed comes at bywind, with sail pointing backwards (since headwind is faster than main wind). During the upwind rear foot is in the front strap, at the downwind it moves back, when jibing even behind the footstraps. Once basic things are in order, sky is the only limit!

Feodor Gurvits

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