brakemeister

ok .. your main concern is ride quality ... Nobody can do everything perfect.... some fold smaller some ride better ...
what you need is reasonable small fold with good ride .... go with a Dahon MU P8 .... best performance bike for the bucks and it folds nice ...
Now .. That Mariner stuff... The Mariner is an overpriced Boardwalk ..Or a Boardwalk with SpeedD7 components and a fancy name ... really way way way back the mariner was a little different than the other offereings.. today all is stainless and alloy anyhow.. no more need to spent extra bucks for the name ... you already know that you need to wash EVERYTHING from the saltwater on a boat anyhow ..

therefore go with a MU P8 .... put some stelvios on it if you want to go fast ( or think you going fast, as the regular thicker Schwalbes will be almost as fast as the skinny ones ..... but its a head thing )

Thor

p.s. what boat ?