mcmaster has plenty of plastic ones and the lowest pressure rating is 120psi which is way higher than what you'll see on a ski:
These 6 products match your selections
Plastic Type
Color For Tubing Type For Use With Specifications Met Nylon Black Polyurethane, PVC Air, Hydraulic Fluid, Water Not Rated
5463K116
$11.84 per Pack of 10
Nylon Semi-Clear White Polyurethane, PVC Air, Hydraulic Fluid, Water National Sanitation Foundation (NSF)
2974K285
11.84 per Pack of 10
Polyethylene Blue Antimicrobial Polyethylene Beverage, Drinking Water (Potable), Food Food and Drug Administration (FDA), National Sanitation Foundation (NSF)
9675T47
6.86 per Pack of 2
Polyethylene White Polyurethane, PVC, Rubber Air, Beverage, Drinking Water (Potable), Food Food and Drug Administration (FDA), National Sanitation Foundation (NSF)
2808K131
8.55 per Pack of 5
Polypropylene Semi-Clear White Polyurethane, PVC Air, Alcohol, Ethylene Glycol, Mild Bases, Water Not Rated
53415K241
8.55 per Pack of 5
PVDF (Kynar) Semi-Clear White Polyethylene, Polyurethane, PVC Air, Beverage, Chlorine, Drinking Water (Potable) 3-A Sanitary Standard, Food and Drug Administration (FDA), National Sanitation Foundation (NSF), United States Department of Agriculture (USDA)
53055K156 1-9 Each
10 or more
7.00 Each
5.45 Each