If you are mounting it at the helm
, you won't need an antenna as the 740/720 has an internal one. This is also likely to work through most fiberglass cabin
tops. GPS receivers
acquire and hold fixes more reliably than in the past.
It's not going to tell you your coordinates any better than the 182 but I think you'll find the larger screen
and color display will make navigation
easier and safer.
Garmin just announced a raft of new products to ship in February. Pricing on the old models may get very attractive.