1. Yes it is perfectly usable for HAM bands.
It can be opened up for extension of transmission
frequencies to also cover transmission
on the marine SSB
frequencies, but even with a HAM license
transmission ont those marine SSB
frequencies is illegal. Only for emergencies.
2. It also covers VHF
and UHF frequencies until 430 Mhz, so it can also act as an emergency
double for your marine VHF
where it will even give you 50 watts (again: illegal, but just in case of emergency
I wouldn't bother).
3. It gives 100 Watts SSB PEP power in a very compact housing; actually it is nearly 100% the same as the Yaesu FT-897 but due to being even more compact even more functions have to be addressed via menus. Like the Yaesu FT-897 the receiver is quite noisy but when away from marinas
4. Does it need a tuner? There is 1 answer to that: it depends on which antenna
(system) you want to use.
If you want to use it "allband" with an isolated backstay antenna or other end-fed sloping wire antenna, you will definitely need an atenna tuner.
You can also use it with frequency "dedicated antennas, not needing a tuner. The easiest and cheapest solution are vertical wire dipoles, cut for 1 frequency, hoisted from the mast
and fixed below on the toerail or lifelines
. Check this topics, from Bill Trayfors.
There disadvantage is that you will need one for every frequency band you want to work
on, and you will be limited by your mast
height to define the lowest frequency on which you can use a vertical dipole (typically 12 Mhz for a 13m high mast.