Step 1
Size and engagement type
Measure the clear opening and confirm screw-in vs quarter-turn vs pop-out.
Identify Your Inspection Port / Deck Plate
Step 2
Brand diagnostics
Look for names and logos in the usual locations.
Step 3
Confirm the details
Confirm by looking at the pictures and detail notes in the sections below.
What to Measure
Measure the clear opening or inside thread area to determine the size family.
Quick checks
- Measure the clear opening or inside thread area first, not the outside rim.
- Use cutout and flange dimensions only as secondary confirmation.
- If dimensions conflict, trust opening size plus thread/seal diagnostics.
Identification Table
Here is a summary table. For more detail, see the guide sections below. Still can't find a match? Send us some photos.
Showing 10 rows.
| Photo |
Brand / Type
|
Diameter
|
Engagement type
|
Hull Dryer Fitment
|
Adapter |
Guide section
|
|---|---|---|---|---|---|---|
 | Beckson & West Marine / Screw-in | 4 in | Screw-in | Optional: Mini | None | Jump |
 | Beckson & West Marine / Screw-in | 6 in | Screw-in | Optional: Standard | None | Jump |
 | Beckson & West Marine / Screw-in | 8 in | Screw-in | Optional: Standard | 8 in Beckson / West Marine adapter | Jump |
 | RWO & Allen / Screw-in | 4 in | Screw-in | Optional: Mini | 4 in RWO adapter or 4 in Allen adapter | Jump |
 | RWO & Allen / Screw-in | 5 in | Screw-in | Optional: Mini | 5 in RWO adapter or 5 in Allen adapter | Jump |
 | RWO & Allen / Screw-in | 6 in | Screw-in | Optional: Standard | 6 in RWO adapter or 6 in Allen adapter | Jump |
 | Sea-Dog Line / Screw-in | 6 in | Screw-in | Optional: Standard | 6 in Sea-Dog adapter | Jump |
 | Seaflo / Screw-in | 6 in | Screw-in | Optional: Standard | 6 in Seaflo adapter | Jump |
 | Sea-Dog Line / Quarter-turn | 6 in | Quarter-turn | Not for Hull Dryer | None | Jump |
Optional Hull Dryer note: Standard = 6 in/8 in. Mini = 4 in/5 in.
Beckson & West Marine / 4-Inch Screw-In
4-inch Beckson / West Marine family; Beckson and West Marine use the same thread profile, and the Hull Dryer fits these directly.
Diagnostic Checks
- Name/logo: West Marine logo is usually on top of the plate, and Beckson name is usually on the underside of the plate.
- Thread profile: Asymmetric thread profile.
- Seal location: O-ring seal on the plate.
- Measurements: 4-inch nominal opening; about 4-1/2-inch cutout.
Beckson & West Marine / 6-Inch Screw-In
Most common direct-fit 6-inch match. Beckson and West Marine use the same thread profile, with West Marine top-logo cue and a plate-mounted O-ring.
Diagnostic Checks
- Name/logo: West Marine logo is usually on top of the plate, and Beckson name is usually on the underside of the plate.
- Thread profile: Asymmetric thread profile.
- Seal location: O-ring seal on the plate.
- Measurements: 6-inch nominal opening in the Beckson / West Marine screw-in family.
Beckson & West Marine / 8-Inch Screw-In
Same Beckson / West Marine family as 4-inch and 6-inch in the larger 8-inch size class; Beckson and West Marine use the same thread profile.
Diagnostic Checks
- Name/logo: West Marine logo is usually on top of the plate, and Beckson name is usually on the underside of the plate.
- Thread profile: Asymmetric thread profile.
- Seal location: O-ring seal on the plate.
- Measurements: 8-inch Beckson / West Marine screw-in family.
RWO & Allen / 4-Inch Screw-In
4-inch version of the RWO / Allen metric-pattern family.
Diagnostic Checks
- Name/logo: RWO logo is typically in the finger depression on top of the plate.
- Thread profile: Segmented threads in the installed ring (metric-family screw-in pattern).
- Seal location: O-ring seal on the plate.
- Measurements: 4-inch nominal class in the RWO / Allen metric-pattern family.
RWO & Allen / 5-Inch Screw-In
5-inch version of the RWO / Allen metric-pattern family.
Diagnostic Checks
- Name/logo: RWO logo is typically in the finger depression on top of the plate.
- Thread profile: Segmented threads in the installed ring (metric-family screw-in pattern).
- Seal location: O-ring seal on the plate.
- Measurements: 5-inch nominal class in the RWO / Allen metric-pattern family.
RWO & Allen / 6-Inch Screw-In
6-inch RWO / Allen metric-pattern family. Use logo placement, segmented ring thread, and plate O-ring to confirm.
Diagnostic Checks
- Name/logo: RWO logo is typically in the finger depression on top of the plate.
- Thread profile: Segmented threads in the installed ring (metric-family screw-in pattern).
- Seal location: O-ring seal on the plate.
- Measurements: 6-inch nominal class in the RWO / Allen metric-pattern family.
Sea-Dog Line / 6-Inch Screw-In
Sea-Dog screw-in family with logo typically on underside of lid and seal on ring.
Diagnostic Checks
- Name/logo: Logo is typically on the underside of the top plate.
- Thread profile: Full screw-in engagement (not quarter-turn tabs).
- Seal location: Seal is on the ring.
- Measurements: 6-inch Sea-Dog Line screw-in family.
Sea-Dog Line / 6-Inch Quarter-Turn
Sea-Dog quarter-turn version uses cam-lock engagement instead of a full screw thread, so it falls outside the supported Hull Dryer fit range.
Diagnostic Checks
- Name/logo: Sea-Dog branding is typically molded into the underside of the lid.
- Lock profile: Quarter-turn cam tabs engage with short slots instead of a continuous screw thread.
- Seal location: Seal is on the ring.
- Measurements: 6-inch Sea-Dog Line quarter-turn family.
Seaflo / 6-Inch Screw-In
No visible name/logo on inspected samples; confirm by rectangular thread and foam gasket on plate.
Diagnostic Checks
- Name/logo: No visible name or logo on inspected Seaflo samples.
- Thread profile: Rectangular thread profile.
- Seal location: Foam gasket seal on the plate.
- Measurements: 6-inch Seaflo screw-in family.
Hull Dryer Fitment
- The standard MarinerX Hull Dryer supports 6-inch and larger inspection ports.
- The MarinerX Hull Dryer Mini supports 4-inch and 5-inch inspection ports.
- Depending on your inspection port, use this guide to find which adapter you may need.
If your port is close but not exact, send photos of top (installed) view, bottom view, and thread view.