The Pontoon Chassis
A “riser bracket” is welded to the top of the pontoon tube.
These brackets support the pontoon deck. Most are on 16” or 24” centers.
Few people pay much attention to the chassis or undercarriage of the pontoon boat. Manufacturers sometimes have cut out pontoon tubes on display at boat shows but most customers assume that one chassis is as strong as another. That’s probably a reasonable assumption on modern boats. But if you are putting a larger horsepower engine on an older boat or buying a boat for use in rough water, its something to keep in mind.
There are various styles of cross channels. Most are the C style (left) Crest uses a box channel with an opening on the top. There are differences in thickness from one brand to another. Thicker always seems better but I know of no failures from weak cross members. The important consideration is probably how many cross members and on 16” or 24” centers. This is probably more important to people that boat in big or rough water. I’ve never heard of a failure on a quiet inland lake.
High performance pontoons like the Manitou, above, have a strong reinforced chassis. The transom and gas tank are in the center pontoon. Elsewhere I talk about how pontoons can twist and flex. Compare this chassis to the one at the top of the page. A pontoon like this may take up to a 300 HP engine.