Is a skid ramp cheaper than a jetty and pontoon?
Considerably, and that is usually why people choose one. You get practical access to the water without the cost of a full jetty, hinged ramp and floating pontoon. If your frontage cannot support a pontoon anyway, because you do not have 600mm of water at a zero tide, a skid ramp is often the most sensible structure you can put in.
How far the ramp has to reach comes down to your tide. Deep water close in needs a short ramp. A shallow, gently sloping bank needs a much longer one to reach usable water at low tide, and that drives both the design and the cost.







