If you open the vent and finger check hole and the main valve to flood the water ballast tank and forget about it, will the boat flood and "sink". I realize the Mac 26X has positive flotation and won't actually sink.
I see in the original brochure and video that they "drilled" a hole in a Mac 26X to flood it and demonstrate its positive flotation. What I can't figure out is with the tank valve under water, letting water into the water ballast tank and air venting from the tank into the cabin, why wouldn't the boat fill with water given enough time?
Somebody please explain this to me. I'm starting to have senior moments and I worry about stuff like this.
Can the water ballast system sink the Mac 26X?
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waternwaves
- Admiral
- Posts: 1499
- Joined: Wed Oct 13, 2004 8:18 pm
- Location: X less in North Puget Sound -have to sail other boats for a while
theoretically
yes, if you had enough weight in the boat to keep the vent lower than the water line it would continue to fill.....bilge probably first....then cabin.....but you would have considerable timeto address the issue...
Unless of course the vent is held 2 or more inches below the waterline because you are carrying thousands of extra pounds of gear... it would not be too hard to figure out a nominal waterplane area at a elevation of hull.....but it is on the order of at least..>>145 ft^2 so each inch of depth displacement requires adding approximately 800 lbs of weight. YMMV, and that is an extremely rough displacement approximation while I sit here inside instead of going out and measuring it on this cold and raining night
Since on my X there is normally 3-4 inches between the normal water level and the top of the vent...that would require 2400 to 3200 lbs of gear to bring the vent to the waterline.... remember tho that wave actions motoring and rocking the boat can momentarily splash water throught the vent easily....
moral of the story.... use the vent whistles, alarms and monitoring discussed on other threads here to avert your wet toesies filling conditions.....
darren
Unless of course the vent is held 2 or more inches below the waterline because you are carrying thousands of extra pounds of gear... it would not be too hard to figure out a nominal waterplane area at a elevation of hull.....but it is on the order of at least..>>145 ft^2 so each inch of depth displacement requires adding approximately 800 lbs of weight. YMMV, and that is an extremely rough displacement approximation while I sit here inside instead of going out and measuring it on this cold and raining night
Since on my X there is normally 3-4 inches between the normal water level and the top of the vent...that would require 2400 to 3200 lbs of gear to bring the vent to the waterline.... remember tho that wave actions motoring and rocking the boat can momentarily splash water throught the vent easily....
moral of the story.... use the vent whistles, alarms and monitoring discussed on other threads here to avert your wet toesies filling conditions.....
darren
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Catigale
- Site Admin
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The front hole on the 
is above the waterline, so water only enters the cabin if it 'sloshes' or heeled....a lot.
If you loaded to the point of being obscene you might be able to get this below the waterline, bit Ive never heard this happening.
On edit - Chip points out that with 15 degrees of heel it gushes, from experience
is above the waterline, so water only enters the cabin if it 'sloshes' or heeled....a lot.If you loaded to the point of being obscene you might be able to get this below the waterline, bit Ive never heard this happening.
On edit - Chip points out that with 15 degrees of heel it gushes, from experience
unless you consider 15 degrees of heel abnormal operation, then no, it doesn't take a lot of effort to leak a lot of water in through the vent.
Last edited by Catigale on Mon Mar 28, 2005 1:04 pm, edited 1 time in total.
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mtc
- Captain
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- Joined: Mon Feb 21, 2005 5:06 pm
- Sailboat: MacGregor 26M
- Location: Panama City Beach, Florida 05 M 'Bellaroo' 60hp Merc BF
excellent question with excellent answers.
please allow me to chine in with a go/no go summary.
in theory - yes the boat can continue to fill past the vent hole if and only if the vent hole is below the surface of the water the boat is setting in.
in theory, most anything can occur. much like if you held the boat under water or the water is above the boat to allow water to enter over the transom, would the water fill the cockpit? yes, it would. is that realistic? no. unless, of course you're in some serious seas where theory can become reality.
in reality, as cat and darren pointed out, it's very unlikely that you would/could overload the vessel sufficiently to lower the vent hole enough; and, if you're going to sail in heavy weather, well you're nuts in this little boat. she's no double ended, blue water bruiser.
so, in reality, no - the boat won't continue to fill under normal operating conditions.
please allow me to chine in with a go/no go summary.
in theory - yes the boat can continue to fill past the vent hole if and only if the vent hole is below the surface of the water the boat is setting in.
in theory, most anything can occur. much like if you held the boat under water or the water is above the boat to allow water to enter over the transom, would the water fill the cockpit? yes, it would. is that realistic? no. unless, of course you're in some serious seas where theory can become reality.
in reality, as cat and darren pointed out, it's very unlikely that you would/could overload the vessel sufficiently to lower the vent hole enough; and, if you're going to sail in heavy weather, well you're nuts in this little boat. she's no double ended, blue water bruiser.
so, in reality, no - the boat won't continue to fill under normal operating conditions.
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Mark Prouty
- Admiral
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- Location: Madison, WI Former MacGregor 26X Owner
Good question. I asked it myself.
http://macgregorsailors.com/phpBB/viewt ... highlight=
She's unsinkable!! Just stay away from those icebergs!!
http://macgregorsailors.com/phpBB/viewt ... highlight=
She's unsinkable!! Just stay away from those icebergs!!
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Chip Hindes
- Admiral
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- Joined: Mon Jan 05, 2004 6:13 am
- Location: West Sand Lake, NY '01X, "Nextboat" 50HP Tohatsu
My 26X isn't lightly loaded, but it's not overloaded either. When it's upright, the vent is several inches above the waterline and no problem. However, when it heels the vent drops below the waterline. As the bilges begin to fill, the vent drops lower, etcetera. You would be astounded at how much water can flow through the open vent with the fill valve also open. I would estimate 8-12 gpm.
This is isn't just theory; BTDT. So unless you consider 15 degrees of heel abnormal operation, then no, it doesn't take a lot of effort to leak a lot of water in through the vent. Fortunately for me, I was oblivious only to the open vent and valve, not to the 4-6 inches of water sloshing around in the cabin sole "bathtub".
Took about forty minutes of effort, hove to, with the bucket and Thirsty Mate hand pump to remedy the situation.
I now have three electric bilge pumps as partial compensation for my potential future stupidity.
This is isn't just theory; BTDT. So unless you consider 15 degrees of heel abnormal operation, then no, it doesn't take a lot of effort to leak a lot of water in through the vent. Fortunately for me, I was oblivious only to the open vent and valve, not to the 4-6 inches of water sloshing around in the cabin sole "bathtub".
Took about forty minutes of effort, hove to, with the bucket and Thirsty Mate hand pump to remedy the situation.
I now have three electric bilge pumps as partial compensation for my potential future stupidity.
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Sloop John B
- Captain
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- Sailboat: MacGregor 26X
- Location: Florida 'Big Bend'. 02x Yamaha T50
Mark, is that an iceberg or an aging Moby Dick?
I havent forgotten about the valve and vent yet; but judging from other omissions, I can see it happening sooner or later.
The normal screw up is to get your boat up out of the water with vent and valve open to drain. Youre on the ramp, and sure, its pouring out fire hydrant fierce.
Then a big ugly guy with a motorcycle hat and tattoos comes over with his knuckles on his belt and growls, you going to be here all day?
Uwuu, no. You elect to drain up on the tarmac, jump in the rig, and haul her out. Out of habit you glance in the mirror and press down on the brake to cause the boat slide on up to the bow chock. Vrrrip!
Next, your drenched mate sticks her head up out of the forward hatch and says, You SOB, itll take me an hour to think up your payback on this one, but youll get yours! Then she slams the hatch shut.
I havent forgotten about the valve and vent yet; but judging from other omissions, I can see it happening sooner or later.
The normal screw up is to get your boat up out of the water with vent and valve open to drain. Youre on the ramp, and sure, its pouring out fire hydrant fierce.
Then a big ugly guy with a motorcycle hat and tattoos comes over with his knuckles on his belt and growls, you going to be here all day?
Uwuu, no. You elect to drain up on the tarmac, jump in the rig, and haul her out. Out of habit you glance in the mirror and press down on the brake to cause the boat slide on up to the bow chock. Vrrrip!
Next, your drenched mate sticks her head up out of the forward hatch and says, You SOB, itll take me an hour to think up your payback on this one, but youll get yours! Then she slams the hatch shut.
26M
In the 26M, there is a cofferdam (cylinder) around the forward vent that is glassed in. In effect, that raises the level the water would have to rise (i.e how far down the boat would have to be pushed) another ten or so inches if the boat is flat and stable.
The water does indeed splash around up there if you neglect to put in the plug, even if you do close the inlet valve on the transom.
If the 26X doesn't have the same thing, it might be worth considering.
- AndyS
The water does indeed splash around up there if you neglect to put in the plug, even if you do close the inlet valve on the transom.
If the 26X doesn't have the same thing, it might be worth considering.
- AndyS
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Bob Zoobricke
- Deckhand
- Posts: 37
- Joined: Thu Jan 13, 2005 7:46 pm
- Location: New Jersey
I have a 2000 X and what I did so I did not have to constantly lift the cushion and wood cover to get to the vent plug in the bow was to install a plastic elbo in the hole and ran a piece of 1/2 or 5/8 clear tubing to a pvc valve, then flex hose from the pvc valve to a through the hull. Now when I need ballast I just turn the valve to the open position press the open button on my Drain Master Electric Waste Valve and the water fills. You can feel the air being pushed out when you do it at the dock. The water never comes up high enough to actually get to the clear tubing so I guess it will not over flow. Since I created a in/out for the water even if I forgot to close the valve the water would just flow out the through hull opening and never into the billage.