Yacht Size Bed Dimensions are one of the mattress sizes which are quite impossible to pin down. There are NO generic sizes. Often a yacht mattress may also be used as a sitting cushion so many yacht mattresses are between four inches and six inches thick.
Yacht mattresses are almost always custom made. Yacht manufacturers try to use every nook and cranny of a Yacht which means that the Yacht mattress often winds up being cut with curves and odd shapes.
Many people these days purchase a memory foam Yacht mattress product because it lends itself to be cut into odd shapes. This is almost impossible with an innerspring mattress. Memory foam works through your temperature to mold to your body and eliminate pressure points for a better nights rest. You may want to consider a memory foam overlay over your existing boat mattress to save a ton of money and add comfort.