Any experience of using a traditional futon on a boat?

[NPMR]

We are considering changing the large stern cabin mattresses and when made to size the cost seems to be coming out at over £600.

A suggestion was made , to use a futon just laid on top of the old foam, thereby saving some £300 odd.

I've used one at home, but never at sea? Ventilation issues? But very comfortable.

Any views?

 

[ithet]

We use a good thickness mattress topper (memory foam) on top of the cabin cushions.