MacGregorSailors.com

Hello,

I am currently repairing/restoring a Mac 26S. While repairing I also took the opportunity to do some mods which have increased the weight. (I added a coolbox next to the sink, 2 batteries (25kg each), solar panel, 120 liters water tank, bow anchor, and a marine head unit).

This weekend while browsing the internet for some stuff for the Mac, I came across a post from an owner who loved the boat but reported that one day due to a malfunction of the water ballast tank while having 5 persons on board (significant amount of weight), the ballast tank started leaking water on board through the air vent to the point that the situation became dangerous. I believe this situation happened due to a malfunction of the bottom valve that, in combination with the weight of the 5 persons on board caused the boat draft . This caused the boat draft to be bigger than normal and therefore increase the pressure on the valves.

Here is a link about another similar situation, however in this case it was caused by misuse of the valves+heavy loading the boat.
http://analogengineering.com/sail/mac/wb.html

Given this situation and also taking into account that both air vent plug and both valves need to be replaced in my boat I was wondering if closing permanently the bottom valve would be a good idea. This way the ballast tank could still be filled/emptied with resource of a water pump. The boat will stay in a marina all year and only be pulled out of the water occasionaly for maintenance reasons.

What do you guys think? Is the idea of closing the bottom valve for good worth considering?

as soon as I step onto my boat or move around inside it I can tell right away if I,m light on ballast & my boat is heavily loaded without ballast

Just sayin thats all

J

I would think that if the transom valve on my is working properly that once I fill the tank and close the valve there should be no more significant pressure on any of the interior valves or plugs. Once closed there is really no pressure being put on the plug other than the occasional splash when hitting a wave or people moving about from cockpit to the forward deck. There would have to be some sort of major malfunction for water to be getting into the hull and getting dangerous even with 5 people aboard.

I came across a post from an owner who loved the boat but reported that one day due to a malfunction of the water ballast tank while having 5 persons on board (significant amount of weight), the ballast tank started leaking water on board through the air vent to the point that the situation became dangerous. I believe this situation happened due to a malfunction of the bottom valve that, in combination with the weight of the 5 persons on board caused the boat draft . This caused the boat draft to be bigger than normal and therefore increase the pressure on the valves.

I gotta see that post...

& Get a new air plug - & a slightly bigger plug, jic.

Anyway,
The valve can easily be replaced, option 1. Option 2 - Go to Lowes or Home Depot & get a 3 or 4"" cap, the rubber one Like this one. & put the cap on when u don't want water ballast incursion. Option 3 - a 3" Ball valve fitted into the end of the female inlet.

U need your ballast when you need it bro. & ur not an or an - So your really need it

& Ditto Highlander...

Gazm, my idea is not to use the boat without ballast (I think a 26S must always be used with the ballast on).

My idea to close the bottom valve is to prevent future malfunction given that the boat will be almost always in the water and corrosion/deterioration of the valves will certainly occur.

Also, considering that the boat will be in a Marina always, the need to empty the ballast tank is not as big as if I would trailer the boat. Since I have electric power supply at the marina I can easily fill/empty the tank in just a few minutes.........

Is there any other reason why this would be a bad idea?

One other factor is it could present a problem when you go to sell it. Of course I'm the last person to ever worry about resale value. I want the things I own to work for me and not worry about the resale thing .

Our S sits lower in the water due to all the mods and that we go out for longer periods so have a lot of provisions on board.



I did something similar to Walt (the link you posted) and have been happy with it. Picture doesn't show it but the riser is plugged. When filling as soon as the water is seen at the bottom of the plug the ballast intake valve is closed.

I also bought and replaced the seals on the bottom intake. Got them from BWY. Since they seal the bottom almost 100% I don't spend a lot of time worrying about filling the boat with water if something happened to either of the two upper vents and don't have any water coming out of them at the moment.

I have installed a bilge pump on the port side and still need to install one on the starboard side for a just in case situation but have never needed to use the one. I do think I'll reinforce the riser shown in the picture above but it has never given us a problem and it isn't exposed to being hit.

Saying all of the above leaving the boat unattended on a mooring or at a dock in the water would present some worry to me, but not necessarily all related to the ballast tank situation. I also wouldn't worry as much tied to a dock at a marina vs. out on a mooring.

I don't think that I would ever permanently plug the ballast intake, but I guess that could be a possibility. I'd just make sure the seal on the bottom valve is doing its thing. I can't see it suddenly not working.

Good luck,

Sumner

On a side note: The last two times we have been out we blew the ballast tank with a pump like the one shown in Walt's picture before taking the boat out. That has made getting the boat on the trailer easier as it sits higher in the water and we don't have to back in as far. We will probably always do that in the future.

============================
1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Wyoming, Idaho, Canada, Florida

Mac-Venture Links

Ricard_M wrote:This weekend while browsing the internet for some stuff for the Mac, I came across a post from an owner who loved the boat but reported that one day due to a malfunction of the water ballast tank while having 5 persons on board (significant amount of weight), the ballast tank started leaking water on board through the air vent to the point that the situation became dangerous. I believe this situation happened due to a malfunction of the bottom valve that, in combination with the weight of the 5 persons on board caused the boat draft . This caused the boat draft to be bigger than normal and therefore increase the pressure on the valves.

The vent on the later boats is under the vee berth. When I haul the boat for a week long trip I put heavy stuff in the bow to counter the heavy fuel tanks (full) in the lockers in the stern. But if I get ahead of myself when launching, and reach under the piles of stuff on the vee berth and open the vent to fill the ballast from the stern water valve, the water can come up inside the "pool", as the author in the link calls what he made for his boat, but is a deep, round cup from the factory on my boat. It could be dangerous in that it can conceivably overtop the cup, so it's on me to be careful.

Or add an extension tube to bring it up a bit higher, with a ball valve and clear nylon tube so I can see if the water is too high. But it's not a problem in actuality, if I pay just a little attention, especially when I have to climb over coolers and plastic bags of clothes and milk crates of food.

If your air vent is not sealing properly, that can be a problem on its own. When you heel the boat, that vent is under water, as it's at the lateral mid-point of the ballast tank, and once you tip the tank, the midpoint is no longer the high point. So I would address the poor sealing of the vent, followed by making sure the fill/drain valve seals adequately (it doesn't have to be totally glued shut to be effective). The fill valve isn't going to let any more water in than the boat wants to hold for what it weighs, assuming it's not totally stern heavy. And when sailing, it's only going to leak some water out of the ballast tank once the boat is heeled, since the water free surface is higher than the water the boat is floating in, and it will leak it back in (over time) once on the mooring again, assuming the air can leak out/in, or compress/decompress a little.

And unless the fill valve is a sieve, and you're sailing for days on a single tack, I doubt you'll lose enough water out the fill valve to even notice.

I don't see any harm in doing what you propose, except that it will be hard to get all the water out of the ballast tank with a pump, or so I would imagine. But I just don't see the utility beyond replacing whatever the seal/gasket is on that valve, and making a more secure vent valve, which you should do anyway.

did you think about monitoring the balast tank water level?
So if you lose water AND see it maybe it will ok for you.

Watch my mod about it:
http://www.macgregorsailors.com/modt/in ... ?view=2094

Ricard_M wrote:....This caused the boat draft to be bigger than normal and therefore increase the pressure on the valves...

One other thing to remember is that these valves are under very little pressure. If you put the boat in the water with the tank empty and the intake valve closed there is less than 1 psi of pressure on it with it being about 18 inches below the water line. With the tank filled the pressure on the vent valves at the top is going to be almost zero and the same can be said then for the intake valve. Renew the parts and you will be fine,

Sumner

============================
1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Wyoming, Idaho, Canada, Florida

Mac-Venture Links

I think you a are overthinking it.

Thousands of Macs out there never had a problem. Why change a system that isn't broken?

Replace the drain and air plug and worry about other things.

--Russ

I replaced my vent plug with a brass garden hose style valve. It gets sprayed with corrosion X every so often.
I also want to replace the fill valve with something better once I figure out what better is.
Ix