if i was doing what you want it for then a furuno fcv 295 for about 4.5 k ( not sure if it is splash proof thou ) or if yu can afford it a fcv 1150 for about 7 K or maybe a fcv 588 at about 2.5 k plus a decent separate chart plotter as well - do use lowrance 2 x HDS units for in the bay etc and that does the job - but imho furuno leaves them all for dead when off shore
cheers