I had one last year when I brought my Scout Troop in to the BWCA.. I had this
TACKLE BOX under my seat... I sat in the stren so I couldn't tell you 100% about the bow, but I'm guessing it would have fit there also.. I pulled the two tackle tray's that came with the box out and replaced them with four of
THESE .. They are half as thick as what came in the tackle box... In other words I got 4 trays in the same space that 2 took up..
To be sure on seat specs, call/e-mail the factory and ask..
My run down on the SR Quetico 18.5:
3 people and gear, it tracked and handled great, nice and stable, we had 2 people paddling and pulled away from everyone in aluminum canoes. However, with my 250# self & fishing gear in the stern, and 110# person in the bow, the water line started someplace behind the bow seat.. Toss in a good cross wind with all that freeboard, stuff gets fun..