If you're replacing a missing or damaged marine seat post, the original Attwood part number is the best place to start. Snap-Lock 1.77-inch pedestal hardware includes short fixed posts and adjustable pedestal assemblies that look similar but may have different supplied components. This chart helps identify the correct family before ordering.

Recognize the Snap-Lock 1.77-inch components

Attwood MPN Part type Height or plate size What to check
29130 Fixed post 13 in Separate mating seat mount
SP-29130 Fixed post 13 in Match exact post and mount
39004 Adjustable pedestal 16–20 in Seat mount included in listed assembly
SP-39004 Adjustable pedestal 16–20 in Integral seat mount
SP-39204 Adjustable pedestal 24–30 in Integral seat mount
SP-69773 Deck base 7 × 7 in plate Non-threaded stainless steel base

Part numbers 29130 and SP-29130 are listed as fixed-height posts. The 39004 and SP-39004 pedestals adjust from 16 to 20 inches; SP-39204 adjusts from 24 to 30 inches. The adjustable assemblies listed here include a seat mount, unlike the separate fixed posts. The SP-69773 is a 7 × 7-inch stainless deck base, not another pedestal post.

Identification and safety: The featured post assemblies carry Attwood's Type B classification, so they are not for a helm or driver seat or for use above 5 mph. The SP-69773 base has an AO component classification, but that does not make a Type B pedestal assembly suitable for operator use.

What to inspect on your existing seat

  1. Find the full stamped number. Keep the SP prefix when searching: 29130 and SP-29130, for example, are separate catalog identifiers.
  2. Measure the post. Snap-Lock uses a 1.77-inch post diameter. Do not confuse it with Attwood's ¾-inch Lock'N-Pin pin system or 2⅜-inch 238 Series.
  3. Check whether the height adjusts. The fixed posts have one specified installed height; adjustable pedestals have defined ranges and include their specified seat mounts.
  4. Examine the mating socket and clip. Make sure the Snap-Lock locking hardware fully engages the original base. Never force an unfamiliar post into a socket.
  5. Compare deck details. The SP-69773 plate is 7 × 7 inches and is listed with a 2¾-inch required mounting hole; that measurement does not describe the screw pattern.
  6. Confirm listing condition and supplied components. These specific UsedRVParts listings are marked Brand New. Check the individual listing for current availability and what is included.

Find the matching Attwood listings

Compare the exact manufacturer numbers and product photos below, then open the listing for current product information. Eligible local viewing and pickup in Kelowna are by appointment.

Other seat pedestal identification references

For different systems, use our Lock'N-Pin seat-post guide, Lock'N-Pin deck-base chart or Attwood 238 Series mounting guide. These parts are not confirmed as interchangeable with Snap-Lock.

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