Hey guys, I've had 'special' GPSes before for my motorcycles before pretty much going to RAM mounted phone, but am a bit lost when it comes to marine options for our new (to us - 1998) 270 SDA.. it has a depth finder currently with a PO replaced (1998-era) transducer, single gauge in the dash with depth which does work, but I'd prefer to at least have some depth maps in combination with GPS... I'd be OK if there were a GPS option that used decent charts including depth as the base, and glancing at the existing depthfinder for confirmation or to use as an offset vs that data. The lake we're slipped in has a fair amount of depth variance and some sections that get fairly shallow. We don't fish currently, so the main use is really simply navigation and depth. I'm fine with adding a RAM mount or other mount to the dash, also fine if there's an option of accurate charts not involving a new through-hull transducer, although I have questions on how accurate they are. Not a huge fan of 'special' GPS units due to the never-ending behavior of paying for 'good' maps, or 'updated maps,' and am aware some units seem to come with more useful to not-at-all-useful base maps... could really use some help sorting out options here. I think there are basically two options here: 1. phone (IOS/iPhone) or iPad based - would provide nav but I'm assuming limited to whatever random depth charts can be used.. ? 2. Some kind of GPS/chartplotter with way too many options to sort - would prefer not adding a new through-hull at the moment as she's likely in the slip until coming out off-season and I'd need to borrow a truck to pull her out (sorting this for future..). I think I've read that some transducers can be used inside the hull although have no idea to accuracy or how/where they'd mount, have seen the 'transom tails' which don't seem a great idea for an SDA to me... If I wind up with another specialty GPS unit with through-hull required, do they start with basic depth maps and I could use until I install the through-hull transducer in the future? I see options in the $400 - > $3000 range at this point, strongly prefer < $1K on this one or a phone or tablet option if a viable one exists.