Enlarged Ballast Plug Hole

[Piddle and Futz]

At great peril of the obvious and lewd comments that may follow, I find that the 1" ballast plug no longer fits in our

At first I thought it had somehow aged and lost elasticity so I purchased a replacement which also rattled in the hole. I'm thinking perhaps some sort of rim insert has gone missing,?

[Russ]

I don't recall any "insert" or gromet. Just a simple hole drilled in the fiberglass.

Can you measure the opening and see if it has somehow expanded?

[Tsatzsue]

They are adjustable. With the lever up you should be able to screw the base clockwise to increase the diameter of the rubber when the lever is pushed down. You may need to give it a shot of WD40 if it has some corrosion on it. I'm sure nothing happened to the hole. There is some thick glass there.
KB

[FittsFly]

Here is an option from amazon if your rubber on yours has deteriorated. This one has a shrader valve coming out of the top because Im experimenting with forcing the water out of ballast without using the outboard to do it but it fit in there snugly and seals the plug hole nicely. Sorry for no photo of the amazon option but this is the description.

No. 6 Winter Rubber Plug with Valve for 1 Inch Fitting, with Blow Thru Valve

[Russ]

Here is an option from amazon if your rubber on yours has deteriorated. This one has a shrader valve coming out of the top because Im experimenting with forcing the water out of ballast without using the outboard to do it but it fit in there snugly and seals the plug hole nicely. Sorry for no photo of the amazon option but this is the description.

No. 6 Winter Rubber Plug with Valve for 1 Inch Fitting, with Blow Thru Valve

Ah, that would probably work well.

https://www.amazon.com/Winter-Rubber-Pl ... B017A8Z38I

[FittsFly]

Thanks Russ, I couldnt figure out how to copy and paste the Amazon item. The other reason I purchased that plug with built in shrader valve was to test my ballast tank for leakage. (Maybe there are other Macgregor owners out there that have wondered if their tanks are actually sealed up good?) so once inserted i started filling tank slowly and with a pressure gauge on my hose to make sure I wasnt over pressurizing, BE WARNED! After only about a pound of pressure I heard a couple "popping " sounds coming from the tank so I stopped right there! I would recommend NOT going any farther as those tanks are made to hold water not air. At that point I found there is a very small bleeder hole centered back below the transom just below where my Suzuki 50 mounts near the large drain/fill valve for the ballast thats literally a mm in diameter that had air forcing out. I believe Macgregor did this for us because if we are trailering from low altitude on land to high altitude with our big valve shut we could literally blow up our ballasts because of pressure change! Please let me know if I'm correct if anybody knows, any way I was able to temporarily plug that little hole with a small stick and with soap and water i sprayed the solution all over the large valve and all exposed areas i could easily get too thru the cubby holes in the boat on the fiberglass tank itself and was happy to see no blowing bubbles any where, then left it filled for several hours and was happy to see I was still holding my 1 lb or slightly less possibly of pressure. Anyway I realize this is off topic but maybe helpful. From now on I've decided anytime I'm trailering I'm going to leave the fill valve and or ballast plug hole open.

[OverEasy]

Hi Piddle and Futz!

On our Mac26X there isn’t a collar or anything…just a hole in the fiberglass to the ballast tank.

What we’ve done is add a bit of PVC pipe and fittings to the vent so we can use an air mattress inflator (that is pressure self limiting) to blow ballast statically without having to be in motion. We’ve only done this when we have the drain valve open …
We haven’t ever really considered doing a pressure check of the ballast tank though… as Fittsfly mentioned the ballast tank wasn’t ever designed as a pressure vessel. His finding of that extra vent hole does have me curious though and when opportunity arises I’ll have to look to see if that exists on our boat…( I suspect not as we’ve been able to blow out the ballast while at the slip with the small mattress inflator).

Best Regards,
Over Easy

[kurz]

About pressur test of Ballast tank


The most of the Tank you cannot See. What will you do there? ?

You could fill the boat with water. The watch and listen of you can See an hear bubbles...

[FittsFly]

Hey Kurz, At first I laughed at your post . Then realized thats not totally ridiculous!, have the boat on water prefferably, grab a nearby garden hose throw it in the cabin and start filling! once the water level got about a half an inch above floor level stop and watch for bubbles! Also a good test for our bilge pumps once you were done.