Inspection Ports on old SF -- (2) six inches okay? Y/N?

Thread starter #1
On my last trip to a marine hardware store I picked up two (2) 6-inch inspection ports and a single 4-inch inspection port.

I also bought 4200 caulk and (mistake, I guess) some Stainless Steel bolts, nuts, washers (expensive). I was in a rush and the store was closing. After I got back to my home in a different state, I realized that locking those inspection plates with both 4200 AND through-bolting them with SS bolts, washers, nylon insert lock nuts was a bit overkill (and more expense that was called for). There wasn't any monster in there trying to get out, and there really won't be any force yanking outward on them. I got the Beck___ (son?) white plastic with screw on lids.

So, my first question: Can I just screw them down with ss screws? What size? (they didn't come with hardware)? I read the other forum posts on Inspection Ports, but still have these questions. Rivets? I don't know anything about them, but am willing bo buy or borrow the gear and learn how to do that (I guess).

The other question is: Can I put a 6 inch port forward (did you say "off center" and can I also use the other 6 inch toward the back/stern? From the really good photos and sketches posted earlier, it looks like most of you go for either a 4 inch or a 5 inch. I've got a 4 inch, but wonder if that will allow enough room for my hands and eyes to remedy "what lies beneath" the deck.
Is a 6 inch Insp Port stretching the capacity of the stern deck to stay strong? I gather one doesn't want to make Swiss cheese of their deck and should put no more holes than are necessary. Should I use the other 6" or return it for a 5 inch.

Thanks for your help. Petrel
A few owners opt to just use the stronger 3M 5200 adhesive caulk only, but most use both caulk and fasteners. The deck does flex - your job will be more secure.

The Beckson Instructions that should have accompanied your ports state:

Fasten deck plate to deck with #8 pan head screws or thru-bolts, maintaining a minimum of 1/16" (1.6mm) of caulk as a gasket and keeping the plate flat. If on a curved surface, fill gaps completely with caulk, without bending the trim ring. ( )

So, my first question: Can I just screw them down with ss screws? What size?

I thought you said you’d already bought fasteners. Can we assume you matched the deck plate mounting hole diameter and the countersink style. That should do it as long as the length is enough. No need to entertain using rivets if you aren’t familiar with them, bolts will be just fine. You need the caulk to make things water tight. Some illustrated guides can be found here -

The other question is: Can I put a 6 inch port forward (did you say "off center" and can I also use the other 6 inch toward the back/stern?

What repairs are you doing, bow handle and rudder plates? Bow handle – 4” if your hand will fit through the raw hole, otherwise 5”. Rudder plates for new backing or upgrade – 5” or 6”. Use the smallest size you can tolerate working through. If you are drying waterlogged foam the bow and stern ports will be all that’s needed for that job too.

For onetime repairs you can re-glass your cutout back in place and not use a port at all. Somewhat more technical a lot better looks.
Thread starter #3
Thanks, Dan.

My SF is old and ratty and patched and I'm going to use it as an aesthetically challenged just-get-on-the-water and play sail board. Initially I had hopes of making the thing fair and beautiful, but since it's got more patches than a quilt, a ratty rudder and daggerboard, and the old brass rudder fittings, maybe it's better suited to more modest expectations. Can I assume it will be dryer and go a tad faster than my old style Super Snark (you sit in a shallow "cockpit" with drain holes on four corners, so it is a wet ride for my butt. The tiller looks like a used boom crutch -- just a hunk of tapered board, fastened close to the stern deck with an aluminum pivot.

I've not put the still drying SF in the water, but did raise the sail DRY and it really wanted to pull the punky hull and me though the grass -- well, almost.

Maybe I don't even need the ports, but I thought I'd dry out the foam and attempt to re-glue the foam blocks ( or pieces of the blocks -- ha) with GREAT STUFF canned expandable foam after the Windline net site.

As for the Yahoo SF site, I started to join that, but there were all these very personally questions in the application form:
Dog's middle name?
Last time you ate (and enjoyed) broccoli?
Have you ever cheated on your Sunfish with another boat?
SS#, blood type, and saliva swab. ... ..
Must have been different back when I signed up. Oh Well, such is the internet.

You'll find the Sunfish a world of difference from the floating styro cooler.
You have already gotten some great advice. But, I thought I would throw in my 2 cents. I just bought (2) 6" and a 4" inspection ports and wish I had went with the smaller 4" everywhere. Since you have one 4" cut the holes for the 4" and then if you need to, open it up to a 5 or a 6". I think the 6" not only looks too big, the curve of the boat will be somewhat altered after installation.

Good Luck. BTW my Super Porpoise is looking like more patch than not also.
Honda CRF450X
Thread starter #6
Thanks, D and BC for the helpful and heartening perspective. I'll start with the 4 inch holes and refer back too the photos in the archives and Windline site.

I use a 6" port up front behind the splash rail and a 5" port to do the rudder upgrade and used ss screws and 3M Marine Silicon to attach and seal.

I tried the "Great Stuff' foam in a can, and it works as long as you don't sail. :) First time you sail in a little chop or bounce over a couple of wakes, you are back to square one.:mad: The "GS" will compress and does not stick very well to the fiberglass or the foam. Dan at Wind Line Sails used a 2 part foam and thats what I ended up with. I used the 4 lb stuff from U.S Composites and it has held up for 4 years now.
Thread starter #8
Thanks, Supercub.

I wonder what "job" I can do with my Great Stuff foam beside regluing styrofoam lobster buoys. It might not even spray again after my "testing" it. I guess you're supposed to use it all in one shot bc the nozzle gets sealed.
I used a Q-tip soaked with acetone to clean out the nozzle, so I might get it to spray again. I appreciate your heads up on the downfalls of the stuff.

I'm sure the blocks are all akimbo in my old, beat up 100 dollar SF hull and I dread having to crawl in there. What would be nice is the gizmo surgeons and gut guys use to scope those hard to get to places (knee, gut, gall bladder). Plumbers also have these (more affordable). A little video camera with nightshot on a long, flexible neck.

Stroke-of-Genius IDEA ;) -- Has anyone thought of just packing their hull space with those inflatable wine bags that come with boxed wine? They hold air pretty well and are made of fairly tough vinyl (or sumpin'). For only $9.99 folks can buy from me a special long blow up wine bag straw :-O
Would the compress air bags add stiffness? Would it be like a Select Comfort mattress and require no butt cushioning with those suffering FFO -- fanny fall out? Think of the fun in collecting your own floatation and "stiffeners."

SoG Idea may need more work and testing. Petrel