Replacing the 6" Marine Hatch Access to the LP tanks

[jd1923]

Our hull is near 10 years old. The PVC was dried out, chalky to say the least and I wanted to replace it last year but never got around to it.

It took me over an hour on Amazon to find one with exact measurements. Most important is the diameter of the screw hole pattern. I found this and after installing it, I like it's better than the OEM. The threads are much larger, easier to turn with less/wider threads, and it seals better.

https://www.amazon.com/dp/B08H4HX29J?ref=fed_asin_title&th=1

As with all things OTT installs, it took me a full hour of labor to remove the silicone caulk. I installed the new one with dum-dum ONLY (what us installers called butyl tape back in the day). Why would you caulk something that does not have to be waterproof anyway? The bottom side of the doghouse is wide open, right? And butyl when squeezed out is waterproof enough.

The original hatch had tiny screws, maybe 1/2" #6 screws. I upped the size to 3/4" #8 screws, drilled the holes out to 9/64" and on the back side I used speed clips on the underside to hold them tight. This way you can torque the 6 screws tightly and evenly to squeeze the butyl.

https://www.amazon.com/gp/product/B08H8STNFJ/?th=1

[dewdev]

What are "speed clips"?

[jd1923]

1 hour ago, dewdev said:

What are "speed clips"?

Click on my second Amazon link for an example. Just like dum-dum the term speed clips is shop talk I learned from other automotive installers in Chicago during the 70-80s. 🤣

They help to install parts faster where you would otherwise have to get a nut behind the item. You can clip these onto sheet metal and they are ready to be screwed down.

However, in the case of this hatch plate, I did not clip them on as that would not allow for a flat seal. I just held the clip on the underside to thread the screw. On the doghouse with 3/16" thick fiberglass you can hardly put a lb-ft of torque to the screw. Turn it more and the fiberglass will crack or shred. With these clips you can torque them down and they will hold tight. OTT made up for the weak screws with extra sealant and caulk.

These clips are great to have on-hand. I was getting low on parts I've had for 40 years and when I found this Amazon listing, I purchased all 3 sizes; #8, #10 and 1/4-20!

Edited April 12 by jd1923

[topgun2]

When a couple of exterior hunks of plastic like this hatch started to show signs of ugliness I took them off, cleaned them VERY well and then used Krylon rattle can paint to make them like new again.  Certainly a bunch less expensive and even a couple of items (like the jack switch cover and the 110 ac cover) that I did about five years ago are still looking good.

Bill

[jd1923]

9 minutes ago, topgun2 said:

cleaned them VERY well...

For sure Bill, and you and I are good ol' school restorers! If you were to paint this part, I would suggest removing the lid to paint and just mask the surround and paint it attached. Removing it and remounting was truly a pain!

In this case, paint would not help. The threads were bad and would stick. Also, check out my cropped pic. There were chips and scrapes in the plastic and a 1" x 1/4" gash in the top opening, just left of the word "close!" 🤣 This part had seen its better days!

[SNY SD UP]

One of the helps I 'found on this forum' with lineup & threading is to mark (small dot, or line) on both the base & cover to show where the threads begin to mate/match-up.

The other is to open that hatch and wash out when you get home (if not when out and about).  it seems to catch a lot of dust in the threads abrading them and make threading more difficult than it should be.

B~Out