Stainless Steel Door roller for my boat

Your roller is very similar to the 81-158. The major difference is that the wheel is 1-1/4". Plus, it's not stainless steel. 

Take a look at the 81-173 roller instead. It has a 1-1/4" wheel and is stainless steel to boot, but it has a different design. Most importantly, it doesn't have that notch in the middle. Take a look at the 81-173 and see if you door needs that notch for the roller to fit. You may be able to get it to work, but I cannot guarantee it.