Water ballast

A forum for discussing topics relating to older MacGregor/Venture sailboats.
OverEasy
Admiral
Posts: 2012
Joined: Mon Sep 28, 2020 11:16 am
Sailboat: MacGregor 26X
Location: NH & SC

Re: Water ballast

Post by OverEasy »

In case anyone is interested in what the geometry is like under the cabin floor is like on a Mac26X:

There are basically three bilge areas in the midsection of a Mac26X. Port and Starboard bilges outside of the water ballast transfer tubes that run fore and aft on each side. Then there is the Center bilge between. These all interconnect via spillover so the limiting height (or depth) of water in any one bilge before it communicates to the next bilge is the water transfer tubes. The aft berth is just about resting on top of the water transfer tubes. The typical battery location of the Mac26X is the little port side bench box aft of the galley. The bottom of the battery typically rests on top of the water transfer tube and the battery clamps to the center facing wall of the bench.

No doubt there is a significant amount of water that can collect in the center bilge and over flow into the side bilges (or Vice-versa) but the water would have to leak out of the four access covers of the aft berth floor and into the interior of the cabin before gaining more height.

(Note 1: There is also the floor cover to the bilges under the dinette where water would flow out of … There is also the standard cutout of the galley for the black insert cubby.)
(Note 2: There are also two smaller bilge areas in the aft stern corners that would also fill/overflow to the other bilges at the height of the water transfer tubes.)

All these openings are 4 to 6 inches below the battery terminal height.

Now if the boat is heeled over to either side the relative water height will of course increase but at the same time will still leak over the hatches and other openings.

But getting the water level high enough to potentially “short” the battery terminals would already have water collecting in the cabin floor.

The aspect of the hole in the cabin floor is a good thing to get water into the bilge as well as acting as a tell-tale that water is in the bilges.
.
Seems like benefits are pretty high compared to detriments.

Just kind of glad that our Mac26X has the hole as do many other sailboats. It seems like not having one would be a manufacturing mistake and not adding one a liability….

Also glad that we pre-emptively added our three bilge pumps and bilge water alarm as personally We’d rather have the pumps available do the work and the alarm sound well before water is sloshing in the cabin and gaining altitude :o :| :?

The peace of mind that some time could be bought should an incident occur is nice to have for us (especially given the awkward accessibility of actually getting to the bilge areas manually).

For us the addition of bilge pumps and alarm we hope to never need is a great investment. :D :D

( As for cleaning up a spilled soda pop getting into the bilge on the Mac26X one can get to the center bilge area via the aft dinette bench to clean up 🧽. Although I’d probably look on it as a justifiable excuse to deliberately do a controlled flood of the bilge with a garden hose to test the bilge pump and alarm 🚨 :D :D )

Your boat, your rules….

Best Regards,
Over Easy 😎😎🐩🐈
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Piddle and Futz
Engineer
Posts: 115
Joined: Wed Sep 29, 2021 7:18 pm
Sailboat: MacGregor 26M
Location: Corpus Christi, Texas, 2005 26M, 50HP E-Tec

Re: Water ballast

Post by Piddle and Futz »

Good points, OverEasy.

On my :macm: there is a solid floor at the dinette and no holes there either, so with the battery box being centered and lower than the :macx:, the bilge could fill dangerously close to flooding/shorting those batteries before overflowing into the companionway floor.

I'm entirely with you on having bilge pumps and alarms. If we are under way, I'm likely at the helm and not monitoring the interior for leaks. Knowing there is an issue ASAP gives one much more time to take action.

(Admittedly, my opinion is based on "exciting" experiences in heavy seas on other boats. I recognize that our Mac will never be blue water worthy, and we probably won't launch it if bad weather is forecast. Nonetheless, I'd feel foolish to repeat any of those close calls when I can easily install 2 bilge pumps for about $50.)
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Jimmyt
Admiral
Posts: 3166
Joined: Sat Jul 18, 2015 9:52 am
Sailboat: MacGregor 26M
Location: Mobile AL 2013 26M, 60 Etec

Re: Water ballast

Post by Jimmyt »

Piddle and Futz wrote: Sun Nov 21, 2021 10:51 am (Admittedly, my opinion is based on "exciting" experiences in heavy seas on other boats. I recognize that our Mac will never be blue water worthy, and we probably won't launch it if bad weather is forecast. Nonetheless, I'd feel foolish to repeat any of those close calls when I can easily install 2 bilge pumps for about $50.)
I think you are wise to be cautious. Just because you aren't in blue water doesn't mean you won't see those conditions. I've seen squalls come up quickly in Mobile bay, turning it into a washing machine. Better to prepare for everything you can imagine happening, cause it just might. And yes, I'm not ashamed to admit I have an 1100 gph (nameplate rating) bilge pump... And testing in-boat shows me that it will keep up with a significant hole; as long as I get it slowed down or start the motor before my house battery dies. :wink:
Jimmyt
P-Cub-Boo
2013 26M, Etec 60, roller Genoa, roller main
Cruising Waters: Mobile Bay, Western Shore, Fowl River
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dlandersson
Admiral
Posts: 4531
Joined: Fri Aug 27, 2010 10:00 am
Sailboat: MacGregor 26X
Location: Michigan City

Re: Water ballast

Post by dlandersson »

Thank you. 8)
OverEasy wrote: Sun Nov 21, 2021 9:15 am In case anyone is interested in what the geometry is like under the cabin floor is like on a Mac26X:
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Highlander
Admiral
Posts: 5982
Joined: Wed Sep 21, 2005 8:25 pm
Sailboat: MacGregor 26M
Location: Maccutter26M 2008 75HP Merc. 4/S Victoria BC. Can. ' An Hileanto'ir III '
Contact:

Re: Water ballast

Post by Highlander »

That hole is there for a safety reason it's too alert U that u have water coming into ur aft bilge their is supposed to b 2 holes the one posted in the picture & another one behind it in the dividing wall inside the battery compartment as someone mentioned before hand. on my boat their was only one hole under the ladder I discovered that the other hole had not been drilled when I was doing mods on my boat & running wires thru that area.
I believe I found this info in the 26M promo video!
So the idea of it is if u see water on the cabin sole for no reason its ur telltale u got water invasion, I believe Roger done this after some 26x had flooding issues in the aft bilge due to center board mounting bolt leaks allowing as much as 1ft of water to accumulated in the aft bilge before spilling over into the cabin sole so it was continued on with the 26M

J 8)
OverEasy
Admiral
Posts: 2012
Joined: Mon Sep 28, 2020 11:16 am
Sailboat: MacGregor 26X
Location: NH & SC

Re: Water ballast

Post by OverEasy »

Hi Highlander!

Thanks for the supplemental history!
Didn’t know of the CB bolt leakage aspect.
I noticed a fair bit of 5200 sealant around the bolt when dropping the CB to inspect and replace the lifting rope…. Guess that history explains all the 5200 used!

Thanks!

Best Regards
Over Easy 😎😎🐩🐈
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