We have a Hydralign 17". Previous owners got it in NZ during their circumnav. They raved about it. We have had Holding Pattern for 18 months now and we have mixed reviews
First the good: Hydralign comes apart as one piece. I understand Max props don't, that the blades disassemble underwater. Hydralign is easy to disassemble, re-pitch, grease, whatever.
Now the bad: we have had to "mess with" it twice in less than a year. Both times the blades have frozen in place, in a "off" position. We were struggling for 3kts. First time is still a mystery why, this time the grease point cap was missing and a bit of "gunk" had gotten in there and I assume this is why it siezed.
It is now sitting here apart waiting for me to re-pitch and assemble today.