Quad Rail bases: length added to the rail

The bases add 3" to total length when installed at the very ends — 1.5" on each end. Example: a 44" rail measures 47" with the bases at the outermost edge.

The bases add 3" to the total length when installed at the very ends — that's 1.5" on each end, give or take. So a 44" rail measures 47" with the bases at the outermost edge.

The math for every rail length

Rail length	Max total install width (bases at ends)
12"	~15"
26"	~29" (often quoted at 28" since the bases don't always sit fully at the end)
32"	~35" (often quoted at 34")
44"	~47"

The "max install width" number assumes the bases are at the outermost position. If you slide them inward, your install width is whatever the rail's length is at the new base position.

Why this matters

Two scenarios where it matters:

Scenario 1 — You're matching the rail to a known gunwale span

If you measured 30" gunwale-to-gunwale and you're trying to figure out which rail fits:

A 26" rail maxes out at 28–29". Too small.
A 32" rail maxes out at 34–35". Fits cleanly with the bases at the end.
A 44" rail also fits, but you'd need to slide the bases inward by about 6–7" total.

Scenario 2 — You're rigging a captain's bridge

Captain's bridges typically need the bases right at the rail ends to clear the gunwales and give you maximum mountable rail in the middle.

For a 26" install width, the 26" rail works because 26" + 3" = 29" effective end-to-end including bases.
For a 32" install width, the 32" rail works (32 + 3 = 35" end-to-end).

On the older Cajo blog post

Some early Cajo content quoted "2" extension" rather than "3" total." The current spec is 3" total (1.5" on each end) measured at the very outermost position of the bases. Use 3" total in your planning math.