Adding a seat to a Jon boat or replacing worn mounting hardware? Attwood offers different ways to secure, adjust or remove a marine seat. A bench rail kit, a clamp-on swivel and a quick-disconnect fitting solve different problems; none should be selected by appearance alone.

Which type of seat mounting hardware do you need?

Slide along a benchChoose the SP-15900 seat-plate-and-rail kit when the bench installation calls for its included 15-inch rails. SP-15100 is the separate aluminum seat plate when suitable rails are already in place.
Clamp or remove a seat15700-3 is a clamp-on swivel with a specified 7½–18-inch adjustment range. For easy seat removal, 11602D1 is a separate quick-disconnect fitting sized for 6¼-inch swivels and plates.
Adjust position or rotation815000 provides 4½ inches of fore/aft movement, 7062-3 supplies a 6-inch offset, and 17720/17721 are different-size seat swivels. Match each to its installation.

Attwood Jon-boat seat mounting parts comparison

Attwood MPN Mounting method Key specification Check first
SP-15900 Bench rail kit Seat plate plus 15-inch rails Match the bench and rail installation; a swivel is not specified in the kit contents
SP-15100 Bench seat plate Plate only; rails not included Use when the existing compatible rails can be retained
15700-3 Clamp-on swivel Adjusts from 7½ to 18 inches Compare bench dimensions and seat mounting pattern
11602D1 Quick-disconnect mount For 6¼-inch swivels and plates Confirm the exact plate size and mounting layout
815000 Deck-mounted slide 4½-inch fore/aft travel; 1⅝-inch overall height Check deck attachment, clearance and seat-side fasteners
7062-3 Seat swivel offset 6-inch offset for added clearance Verify the assembly and seat position before using an offset
17720 Flat seat swivel 6¼-inch plate; 0° tilt Match the original plate and bolt-hole pattern
17721 Tilted seat swivel 7-inch plate; 3° tilt Check both tilt requirement and plate dimensions
What's included matters: SP-15900 supplies an aluminum seat plate and 15-inch rails; SP-15100 is the plate only. Neither listing specifies an included seat swivel. If a swivel is required, identify its plate dimensions and mounting pattern separately.

Before mounting a new boat seat

  1. Identify the support: check whether the existing seat mounts to a bench, pedestal, deck or rail system. Do not treat a bench clamp as a universal deck fitting.
  2. Measure the actual contact area: compare the bench width and clamp range, rail length or existing plate size with the listed manufacturer specifications.
  3. Check the mounting pattern: 17720 uses a 6¼-inch swivel plate with 0° tilt; 17721 uses a 7-inch plate with 3° tilt. Similar appearance does not make them direct replacements.
  4. Keep quick-release size separate: 11602D1 is specified for 6¼-inch swivels and plates; matching this nominal size is not by itself proof of identical fastener locations or complete assembly compatibility.
  5. Plan for movement: leave enough clearance for rotation, the 815000 slide's travel, or the 7062-3 offset without interfering with the gunwale, controls or other equipment.
  6. Confirm the complete installation: verify appropriate fastening, support structure, manufacturer instructions and any required seating classification before using a new mounting configuration.

Shop the matching Attwood components

These cards open the exact manufacturer numbers in the NewRVParts catalog. Products ship from supplier warehouses; in-person warehouse pickup or viewing is not offered.

Attwood SP-15900 bench rail kit for marine seating
Attwood SP-15900

Bench rail kit · Seat plate plus 15-inch rails

Match the bench and rail installation; a swivel is not specified in the kit contents

See exact product
Attwood 815000 deck-mounted slide for marine seating
Attwood 815000

Deck-mounted slide · 4½-inch fore/aft travel; 1⅝-inch overall height

Check deck attachment, clearance and seat-side fasteners

See exact product

More marine seat hardware references

Need a pedestal rather than a bench mount? See our Attwood Lock'N-Pin post selection guide, Snap-Lock pedestal reference and 238 Series pedestal-kit comparison.

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