Thread: Sponson placement
10-04-2010, 12:51 PM #1
Now that I have decided to add sponsons (28" SLX sponsons) to my SL project I have been searching for information on where to drill the holes and put the inserts. I have found the instructions for the Polaris 28" sponson kit which describes how to measure the placement of the rear mounting hole then says to line up the sponson parallel to the bottom of the hull. I have noticed that the bottom of the hull is NOT parallel to the side rub rail. Are these instructions the proper ones for my '94 Sl hull? They don't specifically state which years these measurements are for and I don't want to put them in the wrong spot. Weren't there changes in the SL hulls in later years? Are the rear ends of the SLX's different from the SL's? I also found a set of instructions for Beach House sponsons for SL hulls that show a different method for finding the placement.
10-07-2010, 10:31 PM #2
10-07-2010, 10:58 PM #3
This MIGHT help. Check out the sponson placement on the SL that Slick PWC has for sale.......
10-08-2010, 04:25 PM #4
That pic is great! Looks like he has a pair of skis in his living room!!! Looks like the sponsons are almost up against the rub rail...
If ANYONE has sponsons on an SL, a closeup pic with some measurements would be appreciated...still trying to figure this one out. Not sure why there seems to be so many variations.
10-08-2010, 10:19 PM #5
- Join Date
- Jul 2007
- near Toronto, Canada
When the hull turns it not only leans over, but the rear of the hull also slides sideways (since the jet pump thrust is pushing at an angle). Without sponsons the front of the hull slides some, but the rear slides more, and you make the turn (eventually).
With sponsons as the hull leans and the rear tries to slide, the inner sponsor digs down into the water. The farther forward the sponson the more aggressively the hull will turn (the bow doesn't slide, it turns).
The lower the sponson the sooner it will grab the water when you begin turning.
The more vertical the sponson 'blade' the more it will grab the water.
Set the sponson forward and low with a big vertical blade, and the hull will turn right now and can toss you off easily.
As you move the sponsons up, back, and with a less aggressive blade, the turning gets less aggressive. The sponsons effectively allow you to move the hull's center of rotation rearward and tighten the 'turning circle'.
When traveling straight, the horizontal width of the sponsons can effectively widen the rear of the hull, creating more lift at the rear. This can improve stability at speed and also provide a quicker launch from idle (gets the rear up and the hull onto plane).
The stock sponson locations were selected by Polaris to be a reasonable compromise for recreational riding.
If you want different handling than 'stock', then you have lots of tuning choices
10-09-2010, 04:08 AM #6
- Join Date
- Oct 2006
- Cleveland OH
J, sit tight. I'll get you the dimensions from my SLX hull.
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