Dock Roof Post Mount:
1. Your boat MUST be in the water and next to your dock. Measure the distance that your boat rub rail is from the top of your dock. You will need to measure both the bow and the stern. Let's say your bow rub rail is 22" inches from the top of the dock and your stern is 12" from the top of the dock. Subtract 12 from 22". This leaves you with 10". This is distance that your boat could potentiallly rub against the rollers not including choppy waves. See picture below.
2. Next add 12" to 10" = 22". The 12" is to give you 6" of clearance on both the top and bottom during choppy waves. So in this scenario 22" is your "Rolleaz number." It's the shortest distance of rollers you would need in your application. Since our rollers come in 12" increments, you would need to purchase 24" rollers to protect your boat properly. You always want to go up to the next size from your Rolleaz number. It's always better to have too many rollers for protection rather than not enough.
3. Some houseboats have a roofline that sticks out as far as the bumper rail. In this case, you will either need to purchase 6' rollers or two sets of 2' rollers. One set for low and one set for high.
12" to Dock
22" to Dock
Dock Mount (No Roof Posts):
1. Dock Mounting usually requires only 2' - 3' rollers per set because there is less for the boat to bump against. Here you will see Dock Corners and our Dock Waterline rollers. If you're still unsure what size rollers you need, call or email us, we'd love to help!