Sure, why not? However, I’m curious why you think that a Sit-In that’s only 4" shorter than your Tarpon is going to do a different job in freshwater. Were it me, I’d try your Tarpon 140 a few times in the fresh-water to see how if it works for you.
As far as general comments on the Loon 138, it’s a big, heavy, boat with loads and loads and loads of initial stability. I wouldn’t be afraid to discharge a birding gun from one, if that’s what concerns you. However, when it comes to turning, I’ll bet your Tarpon 140 is more agile. The Loon 138 is like a little plastic aircraft carrier in that regard.
Now, I’m not familiar with your environment, but if you’re freshwater rivers are like mine, then I’d think about a shorter boat. Maybe an OT Otter or similar. The rivers here have a lot of ledges and boulders to maneuver around. Having a short, agile boat is really useful. Don’t worry, you’d fit a 9’ boat. I’m 6’3" and 230ish and have had no problem with fitting the shorter recreational kayaks (OT Otter, Perception Swifty, etc.).
If your mind is set on an OT Loon 138, they’re a good boat sure enough. I’m just not convinced that they’d do any jobs you need doing so differently from your current boat that it merits the cost. It’s your money, though, so what I think doesn’t really matter much.
Loon 138 is great The Loon138 is what I bought to get back into kayaking and I couldn’t be happier with it. Stable, fun, useful, loads of gear space and its easy to get into and out of. I’m 6’6" 270 with a 15 shoe and I have no problem with it. Great boat. BTW, LL Bean says 4 to 5 weeks shipping. It took them 5 days to get me mine.
I like mine, too. No, it doesn’t turn as fast as my OK Scrambler, but I don’t expect it to behave outside of it’s design. The only thing I consistently recommend to people wanting to buy one is buy some float bags, too. They don’t take up that much usable space. If you ever swamp the 138 you will find that it is a booger to deal with. It hangs out with the combing just at surface level and has absolutely NO stability while trying to bail, re-board, and finish bailing. What ever sit in you get take it to a warm safe place to dump it and play around with getting back in. Tight lines.
I’ve had my Loon 138 about 2 weeks. Love it. Tracks as true as I could ask. Only problem is its a bit heavy getting up on the racks above my camper cover, but once up or down, love it, especially the room.
I too like my Loon 138 even though I have only had it for about 2 months. I have a full nylon spray skirt made specifically for the Loon. It sure helps in cool or wet weather. An alternative to LL Bean is www.ozarkcanoe.com. Bill sells OT canoes and kayaks at reasonable prices and ships all over the US. Might be worth checking him out and also his Ebay sales.
Still loving my Loon 138. Its a delight to fish from. I generally carry three or four rods, plenty of room. Still haven’t rigged my rod holders yet, need to get a Scotty flush mount for my spin/baitcaster rod holders. Want the rectangural kind, not hot the round ones, but will probably have to mail order as no one around here carries thme. Just haven’t been able to get on the water enough. Went Easter weekend, but with gusts up to 30mph, fishing was difficult. But the kayak was great in the wind…no water in the boat and tracked true.