MacGregorSailors.com

The question has been presented on Face Book that an individuals 26 M ballast tank will not allow ingress of more than about 65 gallons of water. My thought is maybe a blockage. He is buying an Endoscope to look inside the tank are there baffles in the 26 M Ballast Tank? NO GUESSES PLEASE..

I saw that thread. Did he answer your question about how he measured 65 gallons? How did he fill it?

I saw it too. Had the same question. Thats a lot of trips to the faucet with a 1 gallon jug.

Russ wrote: ↑Tue Mar 03, 2020 5:50 am I saw that thread. Did he answer your question about how he measured 65 gallons? How did he fill it?

He used a flow meter..He is purchasing an endoscope . Now he really needs to find out if there is a port to starboard baffle if there should be NO Baffles he just gets a bit extension and drills thru the obstruction.

Dag Nabit! What was I thinking? My 26M is in the driveway...I got a piece of 3/4 PVC pipe and a bright dive lite and I was able to push 9+ feet up into the ballast tank when the pipe stopped.. OK where are those design blue prints to be found for the 26M?

The original factory site had them. An archive can be found here
https://macgregorsailors.com/resources/ ... ebsite.pdf

In that file is a photo of the bare parts. It looks clear to me where the ballast "tubes" are. They are also visible inside the storage compartments.

It's possible that the factory blocked them somehow. Also, perhaps his flow meter is faulty.

Divecoz wrote: ↑Tue Mar 03, 2020 9:28 am Dag Nabit! What was I thinking? My 26M is in the driveway...I got a piece of 3/4 PVC pipe and a bright dive lite and I was able to push 9+ feet up into the ballast tank when the pipe stopped.. OK where are those design blue prints to be found for the 26M?

There is a blob of permanent ballast in the M. There shouldn't be any baffles of consequence in the ballast tank design. Mine fills completely and drains the full valve diameter till it's done. Then it stops. Baffling wouldn't typically behave that way.

Unless that flow meter has a recent calibration sheet, I agree that it's suspect. Better to drain the ballast into five gallon buckets and keep count.

It is possible that some obstruction has entered the tank, but what are the chances of it repeatedly making a water tight seal?

I'd go to a recycling center and weigh the boat and trailer if I suspected I was carrying around half a tank of ballast.

It's certainly possible that there is a defect in the tank, but you should be able to tell it quickly under sail.

Running a drill would not be anywhere on my top 50 list of things to do when troubleshooting this issue.

I'll shove my borescope in tomorrow and see if I see anything, but I'd be curious how many times he read the low number, and whether he checked the meter for accuracy.

See about 4 min into this.



Shows the ballast tank layout in the hull. The permanent ballast is around the daggerboard, and appears to be glassed to the outer hull if I understood the borescope view correctly.

Borescope did detect light when I went in at the air vent - light source was at the transom fill/drain valve. It didn't appear to be a clean shot, but I was by myself and can't quite reach far enough to fiddle with the light at the transom while watching the camera at the vent . Going in from the transom valve, the inner surface of the ballast tubes is a rough layup on top. The inner hull surface is smooth, though. I saw glass fibers hanging and resin drips, but no blockage. My borescope only goes about 8 ft in, so not able to confirm what happened at 9.5 ft to Divecoz. Could have gotten stuck on a piece of hanging glass from the top of the tube I guess.

I tried the pipe trick but, due to the kink just inside of the valve, I wasn't able to get near the 9 ft mark (using 3/4" pvc I had on hand) without forcing harder than I'm willing for curiosity's sake. Maybe a piece of 1/2" pipe would do better.

If there are baffles in there, I didn't find them.

FWIW, it's more than highly unlikely that there are baffles in there, at least not intentionally. Since the ballast tank is either completely full, or completely empty, both by design, there is no benefit to baffles.

Unlike a fuel tanker, which may travel with a partial load, like an oil truck doing local deliveries (I've driven both delivery and trailer tanker trucks, way back in the day). No baffles means a really dangerous ride with a partial load, as when you step on the brake, the truck slows fast, then the wall of liquid hits and pushes you along. Baffles stop that tidal wave, and the compartments are different sizes so the mini tidal waves are not in sync. They have holes so the fluid can still fill and drain around the baffles, but no big wave action.

But the Mac is like a milk tanker - all the way full (no sloshing, and certainly no tidal waves), or all the way empty. And baffles would slow the intake and draining of ballast water, and there is no benefit to that.

That's not authoritative, of course, but it's something to consider.

Jimmyt wrote: ↑Tue Mar 03, 2020 5:47 pm There is a blob of permanent ballast in the M. There shouldn't be any baffles of consequence in the ballast tank design. Mine fills completely and drains the full valve diameter till it's done. Then it stops. Baffling wouldn't typically behave that way.

Unless that flow meter has a recent calibration sheet, I agree that it's suspect. Better to drain the ballast into five gallon buckets and keep count.

It is possible that some obstruction has entered the tank, but what are the chances of it repeatedly making a water tight seal?

I agree with all of this.

It is possible there was a manufacturing defect that sealed part of the ballast tubes, but to create a perfect seal would be a rare defect and hard to do.

Empy into 5 gallon buckets and count would give me more confidence of my testing method.

Also, is the boat level? If the bow is tilted down, wouldn't that create a big air pocket in the aft sections? I know when I fill the ballast I make sure to rock the boat to purge air pockets. This could be the problem filling on the trailer. Rocking the boat on the trailer to ensure all air is purged would be a good idea as well.


my 2 cents

Russ wrote: ↑Wed Mar 04, 2020 2:14 pm
Also, is the boat level? If the bow is tilted down, wouldn't that create a big air pocket in the aft sections? I know when I fill the ballast I make sure to rock the boat to purge air pockets. This could be the problem filling on the trailer. Rocking the boat on the trailer to ensure all air is purged would be a good idea as well.

Excellent points!

Thanks to each and every one of you excellent job...

I don't know for sure, but I would doubt that there are baffles. As someone said above, they would interfere with dumping out the ballast water. Occasionally, someone would ask where all of the water was coming from. I would say "I'm just emptying my holding tank. Look, there's a brown trout."

well if it was kept in salt water with salt water ballast he might have some sea creatures growing in there & blocked the S/B tube if he was not putting in any pool bleach tablets ?
their must b a bridge connection between the two tubes at the rear stern by the transom to allow the s/b tube too drain

J

This person who is questioning his/her ballast tank; is there more heel than normal? Is there water swishing around in the ballast?

Not being on Facebook, I have not seen the postings. What is it that made this person suspicious? Is the boat not performing well?

Ray