I actually have this one in an XL yellow that I am returning because I found one I like better. It is made for kayaking and won't interfere with high-back seats. Might work well with a pontoon boat. Never used, just tried on. Still has the tags. I'd ship it to you for $65.
You can take a look at what else backcountryoutlet.com offers. I've had a lot of success with them - love their customer service and they ship stuff fast.