Billy I completely disagree that the NVS are earpiercing in the boat. I had the 808s on my X2 (X1/XStar) for 2 years and the thing I enjoyed about them was the fact they projected sound back towards the rider so you could crank them up and still have a normal conversation in the boat.
The only thing to be careful of was making sure they were turned way down or ATT(enuated) when the rider returned to the boat or someone was standing on the swim platform / sundeck. If cranked they would flat out hurt your ears.