Scupper Styles-- Long Term Feedback?

[Ken J]

Like you I only keep a few soft things in there - this Suncat is my third - and best - Compac and they all have the same setup that I have wondered about - and have not sunk yet so I guess all is ok 😜😜

[Roland of Macatawa]

I've not thought about those scupper tubes on my SunDayCat.
Maybe I should; at least take another look.
Roland

[bruce]

Yeah, the critical thing is that the boat doesn't take on water at rest, i.e. the scuppers are above the waterline. If you do take on water underway, due to heeling, loading, or trim, as long as the there is net positive draining, it should be OK. Even if the drain tubes are compromised, as long as collecting water doesn't submerge the scuppers, at rest the water should still drain through the scuppers.

The other issue, of course, is making sure rainwater, or the odd encroachment by a wake or wave, drains adequately. Even on a trailer, if water builds up in the boat bad things can happen. Dave saw how this can happen rather innocently parked under a tree.

[MacGyver]

On the topic about Epoxy and PVC, I did use the combo to repair the rear outputs on my 19 back when I redid the whole boat, When I fixed them I used a product called GFLEX by West System, using it as a carrier, and mixed some glass chop fines into it, then glued that as a joint to the boat, absolutely no issues over the years which also included a few drives across a few states, no cracking or issues are evident.

GFLEX is a modified Epoxy Resin, meant to be flexible. When I was first a part of the product when I received it from West System, I told them I had some testing options to try it on, one test was a set of Rubber boots well past their useful life. That employee used those same boots repaired with the GFLEX for another year and a half keeping his new ones in the box. A year and a half LOL

Mac

[bruce]

Yeah, I've had good luck with G/flex when I needed a flexible bond, although never under much load. They also suggest you can use it with polyethylene and ABS, both very difficult to bond. I'd have to see that!

PVC glues so readily to the full range of readily-available PVC fittings, including flanges, threaded and barbed adaptors, and unions. Pipe can be readily bent with heat to conform to bulkheads for support and protection, or sections of flexible tubing could be introduced. I'd be tempted to work with those rather than relying on fiberglass and sealants as thru-hulls, as some have failed. PVC is strong and cheap, has excellent moisture and UV resistance, and is easy to work. There are plastic thru-hulls with built-in scupper valves if you didn't want to go bronze or SS.

And then there's the access...

[Dave-in-RI]

Took the old scuppers off today and noticed they'd been sealed not just in the screw holes but behind the plastic flange, too. What might take the old sealant off without hurting the gelcoat? Also, I was surprised by the layout of the scuppers. The highest holes are the bilge pump (top right) and just under the tiller seat at the top of gas tank compartment. You'd need a foot of water at least inside to need that. There's also one in the bottom of the gas tank compartment which is at the centerline low. The lowest two, far left and right, are the cockpit drains. Those are below the bottom paint on my boat, so surely would be first to fill, but it wouldn't make it up the cockpit drains without a lot of force. I wonder if the upper gas tank compartment scupper is for routing fuel lines as I've read some people used it for; can't have much useful purpose unless you're just about to sink in a bad way.

[bruce]

Not knowing what the old sealant is doesn't help. There's no need for high bond strength here, so it might just be a weaker polyurethane like Sikaflex 291 (my choice below the waterline) or 3M 4200, or a polysilfide like Life Calk.

You got the flanges off OK, so that's a good start. I would try to scrape off any residual sealant with a hard plastic scraper, PVC would work, or the old credit card trick. I often use bamboo, something that won't scratch the gel coat. Whatever I was using I'd chisel and sharpen the edge on a sander, refreshing it frequently. You could carefully try a dull metal putty knife or chisel, just make sure the edges don't dig in.

I would typically add water (with a little detergent to cut the surface tension), or naphtha/mineral spirits, that would flow under any edges I loosened so I could see my progress. I have tried WD-40 on a silicone sealant with minor success. There are removers marketed for this, I haven't played with these much. DeBond sounds good.
https://www.practical-sailor.com/boat-maintenance/removing-3m-5200

Gentle heat will soften the sealant, clearly you have to be careful not to damage the surface you're trying to protect. Don't heat solvents or removers unless instructed.

I wouldn't use abrasives on any residual sealant beyond what you might be familiar with when polishing a gel coat. I might try grey or maybe maroon ScotchBrite pads with a remover (listed above) or general cleaner, then let things dry and see where you are. White boats are very forgiving.

And then, especially above the waterline, welcome to world of butyl tape!

[Ken J]

As I understand it - if you are attaching new scuppers they come with a rubber flange - at least that?s what I did

[Jim in TC]

I find the drain at the back of the fuel tank compartment (which, with an electric motor is not used for fuel) to be useful when cleaning out that compartment, which seems to collect dirt and debris while in storage and also during the boating season. I can simply flow some water through. The bottom scuppers on our Sun are also lower than the waterline on the sides, not painted on the transom since it is above the water there.

[Dave-in-RI]

I finally found time to go to West Marine and pick-up some cheap flapper scuppers yesterday (1yr old and 3yr old = never time for dad)-- what a ripoff! They wanted $21 for a single flapper style scupper in the store brand. Since I needed 5, that would've been $125 for a dollar's worth of parts! The Compac supplied ones say SeaDog on the flapper, which you can buy new right now from Bass Pro Shops for $5 each-- $100 less total. I left annoyed, and just came on to buy some online. Out of curiosity, I ordered the plastic flapper kind rather than the rubber flapper that curls. Amusingly to myself in regards to the above, these were $12.99 each (plus $10.99 shipping... but hey, better than $21-- and I get the learning experience of trying the new material). I came close to ordering the duckbill style for the lower set of three holes, but would have no way to clean out the two from the drain pipes should "things" find their way down into the long PVC tube. The bottom gas tank compartment one I could do, but I'd have to measure-out if it'd hit the rudder head and even still, that one I know I'd want to flush out. So, I'm half-reluctantly going with the plastic flapper kind all around, and may wind up ordering one rubber "regular" kind from elsewhere just in case the flapper won't work up top when I run the fuel line out from under the tiller. Just sharing my thoughts here for posterity's sake...

Got These:
https://thmarinesupplies.com/products/flush-mount-scupper-valve-assembly


They do sell a kit where you keep the white outer rings and add their new flappers, but mine were all marked up and I figured just replace with what they think fits best. Kits were $19 for 2 sets of flappers (2 for one size, 2 for another-- it's not 4 of the same like it looks in the photo):
https://thmarinesupplies.com/products/scupper-flapper-repair-kit

[Dave-in-RI]

Scupper replacements came last night. Unsure if they'll fit yet, but some initial observations and pics. I got white on white (which allegedly is still UV resistant, though the white/black tie-wraps come to mind... most white ones can't take the sun).

1) They do not come with screws for putting into the transom; save your originals (I did). The collar/flange/trim appears taller from memory (haven't held it up against the original), and has recessed screw heads, so I'm hoping the old screws give equal extension out the back as the old ones.

2) The "plastic" flapper feels suspiciously like rubber to me. It's not smooth like the outer ring, it's "grippy" and flexible. Here's to hoping it doesn't curl like they promise.

3) The OEM (SeaDog) rubber flappers had the black flapper fully secured all the way around by the collar/flange/trim screws. On these T-H Marine flappers, it is only secured with a "set screw" at the top. Not sure how much strain / wear & tear it'll encounter, but I would've liked to see more attachment points so A) I dont irrationally worry it'll fall out, and B) I had a gasket running around the collar/flange/trim. Assuming the old screws fit and are long enough for this, I'm now going to put some sealant beneath rather than just in the screw holes.

4) Also included a pic from the Sea Dog site, where you can see the full coverage / behind-the-screws flapper plus gasket. Maybe I can re-use the old gaskets with some new adhesive...

(note- This forum randomly makes some images auto-load HUUUGE.... not my fault!)

[Dave-in-RI]

Well, they do not fit due to the holes Compac drilled being in a different orientation. I don't feel like drilling new holes; would rather just double up on flapper ones. See pic:

[bruce]

Sorry the holes don't line up, even the same manufacturer can change things.

If you really want to use the T-H scuppers, you could fabricate mounting rings out of 1/8" aluminum for example. One set of holes to mount to the boat through the existing holes (well bedded), a second set of holes tapped to receive machine screws spaced to conform with the T-H layout (bedding not critical). 1/4" StarBoard would work, I'd go to 1/4" because threading in plastic is not as strong. Aluminum is easy to machine, stainless would be a pain.

Don't place too much stock in the rubber vs. plastic question, neither has a precise definition chemically. Rubbers generally have some elasticity, the ability to recover its original shape after deformation, whereas plastics generally deform more permanently (beyond a certain point). But, there are compounds that bridge the gap. Santoprene is an example. Some rubbers and plastics are formulated to have good UV resistance, but not all do. T-H doesn't say what their flappers are.

Similarly, pigments in general aid in preventing damage from UV. You mention cable ties (Nylon 66), and black, with pigments, is more durable than clear in UV. But, there are white pigments that are very good at blocking UV as well. Titanium white is excellent for example. Zinc white, somewhat more transparent, is used in sunscreen formulations for its UV protection. StarBoard (HD polyethylene) is formulated in white and black colors (and others). The pigment helps in UV resistance, but they also include UV stabilizers in their formulation to make the product durable in the marine environment.

Easiest to stay with what you've got. If you don't like the replacement flappers Sea Dog sells, you could cut your own out of rubber sheet. EPDM comes to mind, available in white and is used for industrial roofing. Lots of choices, full range of hardness, some have fabric reinforcement. McMaster Carr is a good source.

[McNemo]

I just undertook this same operation last weekend. I opted to reuse the original sea-dog flaps, and turned them BACK to logo facing out, which I presume the PO did the exact thing once before. I found the old sealant came off cleanly with a razor blade, and if you attack it at a shallow enough angle it will not damage the gelcoat. All scuppers were rebedded with 3M 4200 save for the upper port scupper as that one is just going to serve as the through-hull for my fuel line. I will probably use a spray bottle of armorall to treat the flaps occasionally for UV protection. Perhaps that might slow the curling a bit.