Are you wanting it to look like an architects drawing or the architect drawing image is the boat you want on the shirt?

You mention wanting a hand drawn look but don't want many details. In order to have the feel of being hand drawn there need to be those small details that look like pen/pencil/etc strokes.

Thanks so much for asking for clarity. I would like the it to look like an architects drawing. The boat picture that is head on with two people is the perspective and the tunnel hull cat that has a full canopy is the actual boat shape we are looking for

My apologies... hand sketch or architect type line drawing.