Water ballast vent

[BOAT]

The first I read about this issue on this site a few years ago I reacted the same way mike did - everything he said is right and he is just trying to talk to common sense.

I guess it's a subject worth reviewing on a regular basis - I am willing to discuss it every year if need be because it's a rather important thing that is very unique to our boats and the entire boat community looks at the whole "water Ballast" thing as a point of contention among boaters.

With that: Be it known that THEE most important issue about the MacGregor is the water ballast system - there are labels and warnings all over the boat and in the owners docs to that effect. It gets more press from the factory than failure of the rigging, steering, or hull. It's obviously a 'big deal' to the factory. The main rule from the factory is that the tank MUST BE ALL THE WAY FULL OR ALL THE WAY EMPTY - no in-between. The warning label is clear that a partially filled tank will make the boat unstable and lead to possible injury or death. That means the operator KNOWING the level of the water in the tank is CRITICAL to the original designers of the boat. Be it an inspection hatch, pilot light, a finger in the vent hole, water in the bowl, or the factory provided clear tube for testing the water level - KNOWING THE LEVEL IS CRITICAL TO SAFE OPERATION. I think that is pretty clear.

Any dispute to that need not be discussed here. If you don't agree then I would see that as a personal decision, (like religion), not a way to operate the boat.

[Pizzanova]

I haven't even got my 97 wet yet and I already know this ballast thing is going to be a nuisance. As you know on this version the ballast vent is located under the step. What was Roger thinking? I'd like to relocate mine to the forward berth area but I'm not sure if I can just drill a 1" hole and tap it to a vent tube and just where exactly should I drill?

[dlandersson]

By George, I think he's got it.

Am I missing something here, the whole vent thing is basic science, year 7 stuff.

Why vent when filling, - Vessel has a limited capacity, when the tank is empty that is full of air, so if we want to replace the air with water we must provide somewhere for the air to go, if we dont the tank will never completely fill, during the initial period of filling as the water level rises the air can escape from gap between the the actual water line and the top of the inlet valve, once the water line rises to the top of the inlet valve unless there is a vent for the air to escape the water level in the tank wont rise because the tank is full to the waterline of the inlet valve, the rest of the tank is full of air. unless there is a way for the air to escape the water level will never rise because the tank is full (with a mix of water and air), to allow the tank to completely fill you must allow the air to escape to give room for the water in the tank.

Same when emptying except we have a helping hand from gravity or venturi effect , basicly the water can only escape from the tank at the rate that air can enter remember our tank is always full, of course that can be with water, air or a combination of water and air.

In its simplest form, we open the gate valve on the ramp, water will still come out even if we dont have the air valve open, but slowly, thats our dear friend gravity helping out, water will continue to flow until the vacuum created in the tank by gravity allowing the water to flow is actually stronger than the gravity allowing it to flow out, at this point the vacuum takes over and draws air into the tank and you will see the water sort of gulp as the vacuum draws air into the tank, the flow will then continue until once again the vacuum takes over and draws more air, as the water level drops in the tank there is more room for air so its longer between gulps,

If the system was open (air valve open) the water can continue to flow out of the gate valve at the rate that the inlet of the air valve allow water in, limited by the diameter of the gate valve, of course because the diameter of the gate valve is larger than the air inlet the air cant keep up with the water flow out so you will still get some gulping as the tank empties through the gate vale.

There it is simple You can try this with a soft drink bottle in your sink at home, take the lid off and lat the bottle on its side and push it down, without a vent the water can only fill the bottle until the volume of air wont let any more water in, now put a hole in the top of the bottle, the water will now completely fill the bottle, put you finger over the hole you just put in the bottle and hold the bottle out of the water, the water will flow out very slowly, noe take you finger off the hole, the water will flow out much faster as the air fill the space the water once filled.

Remember your ballast tanks are always full, just full of air, water or a combination of water and air

[dlandersson]

Mine is under the step. It's very convenient. Just check it when you're "settled" and you might want to put a chlorine tablet in every now and again.

I haven't even got my 97 wet yet and I already know this ballast thing is going to be a nuisance. As you know on this version the ballast vent is located under the step. What was Roger thinking? I'd like to relocate mine to the forward berth area but I'm not sure if I can just drill a 1" hole and tap it to a vent tube and just where exactly should I drill?

[March]

Pizzanova wrote:
As you know on this version the ballast vent is located under the step. What was Roger thinking?

Nah, not to worry. checking the water level under the step is easy. It's in plain view and the light that comes through the companionway makes it a cinch Make sure your stopper is handy once you see the water level close to the top, or else, you'll get water in the bilge
It would take a lot of water in the bilge to sink the boat to such an extent, as to bring the level of an unplugged breathe hole under water level.
I think it happened to one member. But as soon as the water started sloshing in the boat itself, the dude figured it out, plugged the hole, mopped all the water and dumped it into the sink--from whence it was bailed out--in case he didn't have a bilge pump, can't remember
I think there's room enough under the step to add a short breathing pipe,that would raise the critical level even more, but I don't think it's necessary, as long as you have an extra stopper just in case, and pay attention

[kurz]

- they wanted to make sure I could see water in the bowl or in the hole so that I could confirm the tank was full and that is exactly why I removed the hose from the vent hole and put a clear plastic cover on it - so I could SEE it. The next best thing would be an indicator light like you have.

Or if you have the vent tube - just drill a new whole with a factory made plug.... easy as it is...

I have all three: LED control, vent tube tu ancor locker and a third whole with a plug. Best of all: Very low cost ...

[BOAT]

I haven't even got my 97 wet yet and I already know this ballast thing is going to be a nuisance. As you know on this version the ballast vent is located under the step. What was Roger thinking? I'd like to relocate mine to the forward berth area but I'm not sure if I can just drill a 1" hole and tap it to a vent tube and just where exactly should I drill?

Really - in general regular use it's not that big a deal - you might forget to fill the tank and go sailing or skip the plug and get a little water in the bilge or blah blah blah . . . it's not really an issue for MAC owners of today because the factory started screaming from the rooftops back in the late 80's about running the boat without ballast. If your not intentionally driving the boat hard into the wind with an empty tank or making turns at 18 MPH with 11 people on top of the deck with no ballast you should be fine.

The reason this all happened is because it was not always that way - in fact - when the water ballast thing first came out in the late 70's lots of people were going real fast by dumping the ballast - it was a common practice that the factory "sort of ignored" wink wink and was actually a marketing tool "you can dump the ballast downwind and really take off" some dealers were reported to say. I myself could not wait to get hold of an 'unballasted' MAC ant try it out to see how fast I could go. (It just took me many years to get up the money to buy one).

It was all about racing and speed and stuff and it was common for people to run downwind with less than full ballast and play all kinds of games on the water to go faster. I don't know what happened but long before any boats actually capsized the factory started slapping warnings all over the boat about running without a totally full ballast tank. I assume it was the litigious era of the late 80's and early 90's (where MacDonald's would get sued for hot coffee being 'hot') that probably prompted the lockdown on ballast manipulation while underway.

So - there you have it - I will not tell you what I ACTUALLY do on the water but here in public on the website I assure you I will only walk and talk the company line.

[sailboatmike]

IMHO running with less than full ballast may be fine in light winds, my concern is Im not sure if the tanks are baffled, if they are baffled to stop the water sloshing about when only a percentage full the ability to dump and take in ballast when required would be awesome, without baffling its just outright dangerous as all that water free falls from one side to the other

Totally without ballast she is not much more than a very big dinghy with a lid.

Does anyone know if the ballast tanks are baffled?? I would hope that Roger would of thought of that, but who knows

[bobbob]

Pizzanova wrote:
As you know on this version the ballast vent is located under the step. What was Roger thinking?

Nah, not to worry. checking the water level under the step is easy. It's in plain view and the light that comes through the companionway makes it a cinch Make sure your stopper is handy once you see the water level close to the top, or else, you'll get water in the bilge

No you won't - when the ballast tank is full the water level comes up to about 3" below the stopper hole.

[Baha]

Maybe it's just me, but filling the ballast after launching has not been an issue, even single-handed. On my , I just make sure the plug is out before launching, then, depending on wind, current, etc pull open the gate valve. If weather and water permits, I do like to wait until I am tied up somewhere to do this, especially when by myself. I usually check it every morning if I am out for a while.

How many of you empty your ballast before recovering? I have not, largely because it is usually windy and I have a pretty good side current at the ramp I use, and I have a tow beast that doesn't mind the pull at first. I do stop ASAP and let it drain on the ramp.

If you have a good technique for this in less than ideal situations, please let me know!

[dlandersson]

This has been my experience also. Never had it slop over.

Pizzanova wrote:
As you know on this version the ballast vent is located under the step. What was Roger thinking?

Nah, not to worry. checking the water level under the step is easy. It's in plain view and the light that comes through the companionway makes it a cinch Make sure your stopper is handy once you see the water level close to the top, or else, you'll get water in the bilge

No you won't - when the ballast tank is full the water level comes up to about 3" below the stopper hole.

[bobbob]

Maybe it's just me, but filling the ballast after launching has not been an issue, even single-handed. On my , I just make sure the plug is out before launching, then, depending on wind, current, etc pull open the gate valve. If weather and water permits, I do like to wait until I am tied up somewhere to do this, especially when by myself. I usually check it every morning if I am out for a while.

How many of you empty your ballast before recovering? I have not, largely because it is usually windy and I have a pretty good side current at the ramp I use, and I have a tow beast that doesn't mind the pull at first. I do stop ASAP and let it drain on the ramp.

If you have a good technique for this in less than ideal situations, please let me know!

This is my experience - when I launch the boat it takes me far longer to get everything ready than it takes for the ballast to fill. When I retrieve I do what you do, pull up onto the ramp and let it drain.

[BOAT]

Maybe it's just me, but filling the ballast after launching has not been an issue, even single-handed. On my , I just make sure the plug is out before launching, then, depending on wind, current, etc pull open the gate valve. If weather and water permits, I do like to wait until I am tied up somewhere to do this, especially when by myself. I usually check it every morning if I am out for a while.

How many of you empty your ballast before recovering? I have not, largely because it is usually windy and I have a pretty good side current at the ramp I use, and I have a tow beast that doesn't mind the pull at first. I do stop ASAP and let it drain on the ramp.

If you have a good technique for this in less than ideal situations, please let me know!

This is my experience - when I launch the boat it takes me far longer to get everything ready than it takes for the ballast to fill. When I retrieve I do what you do, pull up onto the ramp and let it drain.

I agree - me too - After the boat slides off the trailer I tie it to the dock at the launch ramp and then I open the rear valve. By the time I get the daggerboard down and the rudders and get the motor in the water and started the tank is full.

When I come back to the dock at the ramp the first thing I do is open the valve, then pull up rudders and DB and motor and stuff - when I get the boat winched up a lot of the water starts to leak out (I guess cuz the trailer is uphill) as I slowly winch up the boat more an more water leaks out. The rest comes out when I pull the boat up the ramp.

[frede]

I don't take her out of the water much but before I do, I open both valves. I leave them open till after I put her back in. Is there a reason I would want to close them before I put her back in?

[BOAT]

I don't take her out of the water much but before I do, I open both valves. I leave them open till after I put her back in. Is there a reason I would want to close them before I put her back in?

Not really - the reason that I close the rear valve when on the trailer is because I like the boat to float off the trailer easy when I launch it so the extra air in the tank makes it float off in shallower water but you can still launch it with the water pouring into the tank - you just need to go a little deeper down the ramp to get it to float - that's all.

(The other reason i keep the back closed is silly because one time my depth sounder started making clicking sounds on the trailer cuz i was updating the chartplotter and I did not know what the sound was so i thought animals crawled into my ballast through the back hole but the guys here all laughed at me and said it was just the sounder getting activated when I turned on the plotter - I guess it makes a loud noise if your not in the water )

So I keep it closed so crickets don't get in. it's silly.