Frame Basics

ArticleJune 04, 2011
Frames on the Middle Fork

Besides the boat itself, the frame is obviously the most essential piece of equipment for a cataraft and for a raft hauling a lot of gear. As with boats, there are many frame options in terms of style, function, quality, and performance. Here are a few points to consider no matter which frame you choose:

Q: How do I know if a frame will fit my boat?

A: There are two key frame measurements: “center-to-center” and “flat length”. Calculate the “center-to-center” measurement by taking the width (outer dimension) of your raft (this is not necessary for a cataraft) and subtracting the diameter of one tube. For “flat length”, measure longwise along the relatively flat surface of a tube or pontoon; this measurement will indicate how long your frame can be.

See our Inflatable Boat Frame Sizing Guide for sizing for specific frames.

Q: Custom vs. ready-made?

A: Some frame manufactures design frames to accommodate a specific arrangement of gear. In these designs, cross bars and oar mounts are in a fixed location. While these frames may come apart in sections, their basic dimensions cannot be changed. Modular frames, like the ones NRS builds, allow you to move your seat bars, cross bars, and oar mounts. This allows you to adapt the frame setup from play boat to gear boat with very little effort. Modular frames are also easily broken down for transporting or storing.

Q: “Fixed” vs. “modular” frame?

A: Custom fabricators can take your boat’s measurements and other specifications and construct a frame to meet your exact needs. Ready made frames are available through some boat manufactures. NRS specializes in a “combination frame” which, because of its modular design, functions like a ready-made with customizable options. These options include extra seat bars, special fishing components, and breakdown side rails. NRS can supply frames to fit nearly every boat on the market today.

Q: What additional components can I add to my frame?

A: Raft frames generally can be outfitted for special activities. For example, some designs incorporate features for fishing, like thigh bars, swivel seats, stern-mount seats, and anchor systems (for catarafts and rafts). You can even get walking or running boards along the sides of the frame; these are typically aluminium, diamond-plated steel, or marine-grade plywood. These boards make it easier to step on and off the boat when loading and unloading. Aluminum, mesh, or marine-grade plywood can also be used for different flooring set-ups in catarafts or rafts.