On a boat, I think that it would be better to have speakers from Bose's weather-resistant line, the best of which are the 802 Series III.

Bose had a problem with premature foam rot on the 901 Series III, IV, and early V, so they had a generous trade-in policy. I exchanged my 901 Series IV with EQ for the Series VI, at a modest price. I don't know if they still do that.

The biggest change in 901's was between Series II and Series III. I owned the IV and the VI for 19 years. I've never heard the originals or the Series II. Alan, how do you think the sound of the II compares to the III and IV? I know that the II could go deeper in the bass, with a powerful enough amp and the bass filter disabled.