Ballast vent

[Russ]

"btw... how many have a toilet seat indicator at the helm - is it up or is it down?? "

I do...If it's up, I hear a loud screech from the Admiral!

Good one.

as for the vent indicator. It's not a must. However, it would be nice to know for certain that the tank is full. I'm sure that for most of us, we get it full, however, if you were into gadgets, it would make a fun mod.

[raycarlson]

That's the nice thing about the anchor locker drain-vent mod, there is no need for any valves, electronics, indicators, nor does anything need to be done by the operator other than to open or close the ballast valve at the transom. Nothing will overflow, you don't have to leave the helm, and a peek over the back of the transom will tell you when the ballast is empty or full, pretty much simple and uncomplicated as it can get.

[BOAT]

I disagree with the notion that ALL Mac owners need a ballast tank indicator. Because one person failed to maintain a simple system does not mean that the simple system is faulty and therefore should be replaced by a complex system. Some people favor gadgets and will justify the need to gadgetize anything to forgo the effort of verifying a status with their own senses. To each their own.

btw... how many have a toilet seat indicator at the helm - is it up or is it down??

I do, If I am close hauled on a starboard tack in the late afternoon when the wind is strong I can hear the lid slam closed when the bubble goes past 20 degrees. ("Ooops, left it up again").



Yes, this may be just a little bit too much "gadget" for most people including the bypass switch in the compartment there and the water tight flex and boxes and stuff - it's all gasketed in case of a flood like in the navy books I read. I was out sailing a few days before the rain started coming down so that is why you can see water drops inside the water tight bowl because sea water was splashing around in there 4 days prior. The sight glass is probably all that is needed to check water level as in the case with 'boat' because 'boat' is still pretty new and nose heavy so there is always water in the bowl when underway reassuring me that I am full. The factory manual states to check the water level while underway regularly to make sure the tank is full. That is easier with the sight glass because I do not need to remove the plug - I just lift the hatch and take a peek. When 'boat' is older and has more junk in the trunk and heavier she will ride ass heavy like most of the rest of the M fleet does because we tend to load up so much crap inside. At that point I will no longer be nose heavy and the water will not come through the hole - that's when I will worry more about a gauge, (and a dual trailer), but for now I am still pretty stock. I have tried to total weight my mods to total less than the stock table I removed. I think I am still not too much over stock weight. When I am no longer nose heavy i will put all my fresh water tanks in the bow like Highlander does to get the nose back bown again. It's important in the M to keep the nose down - the boat will point better and heel less with a heavy nose. Of course, then I will need a bigger trailer.

[BOAT]

That's the nice thing about the anchor locker drain-vent mod, there is no need for any valves, electronics, indicators, nor does anything need to be done by the operator other than to open or close the ballast valve at the transom. Nothing will overflow, you don't have to leave the helm, and a peek over the back of the transom will tell you when the ballast is empty or full, pretty much simple and uncomplicated as it can get.

Been there done that. It works great except you can't see into the vent hole because there is a hose fitting in it so you never really know if your are 'FULL', even with that I was told by the factory that for most sailing that was okay, but i was warned to PLUG THE HOLE in heavy seas because plugging the hole helps prevent leaks at the transom gate and pressure on the screws holding the gate in place.

Pitch-poling with a partially full tank could blow the gate valve if your screws are loose or stripped. If you ever get in a storm at sea - remove the chain locker hose and plug the vent.

[Russ]

You know BOAT, your posts here tend to come off as a troll or goofy. However, I've looked at your mods and you are a quite talented craftsman. Granted, your submarine hatch is overkill for most, it's done extremely well. Wiring is top notch and ultra professional looking. Looks like you ran a dedicated vent into the chain locker.
So why did you change this to the clear submarine hatch? Seems it would do what you wanted. You could see water in the hose if it were full. Especially if it's bow heavy. As you mentioned, bow heavy seems to be preferred for performance.


I still think the valve is overkill. A vent to the chain locker would eliminate the need for a valve completely. If the aft valve is closed, water can't escape regardless if the vent is open or not. It's just a vent. The only real reason for a plug (or valve) is to keep water from sloshing out in heavy seas. A vent up to the deck would do that also.

Your lighting mods are excellent also. AC power looks well done.
What I'm most impressed with is your table mod and backrests. Very classy looking and functional. The white cushions look nice also.



Also, for those of us who have experienced the cheap creaking and cracking of the aft berth, your solution looks very solid and professional. Better than factory original by far.



You really should publish some of these to the mods section. I only wish I had your carpentry skills.

--Russ

[BOAT]

I was told the concern was that an open vent hole is a potential for a 1000 pounds of water to slosh fore and aft in a heavy sea and pound on the gate valve. They said an air bubble allows movement even if the air bubble does not move because air is compressible. I know - they did not have the time to explain it to me. I went again to the Naval books for an explanation of what the factory was trying to tell me. Basic Submarine fundamentals: Water in not compressible, so by eliminating all the air from the tank you eliminate the amount of space in which the water can move. Because water is not compressible it will only move into a void where there is air - which IS compressible. The least amount of air you leave in the tank, the least amount of SPACE the water can compress and displace, and thus the least amount the water can MOVE. If you have a large air space in the tank, the water can compress that air and move right in - back and forth - sloshing like a wave. The wave pounds on your gate valve. Now - the hole is small, so the displacement can only occur as fast as the hole can drain the tank so it's not a big deal in most cases - but over a long period of time, (like in a storm), if enough water is forced out the vent hole the airspace in the tank becomes large enough for the water to 'shift'. In the case of a fore aft shift, it could be quite a pounding. In a normal situation you just open the gate and let the water back in but in a storm?? It's not that easy. Opening the gate in a 20 foot sea could lose more water than gain. I like the bowl open so if water gets into the bowl the water can drain back into the tank, but mostly I wanted to be able to see into the hole when underway. (I also went to a MUCH larger hose and valve so the tank drains just as fast as it did when there was no hose at all).

Yes, the vent goes all the way to the chain locker:



As for the troll thing, that's what trolls are - they are usually good with their hands and can build simple structures like bridges and toys but because of their smell and poor disposition they seldom are allowed to work with others but do quite well on their own. Most people don't like trolls.

[kurz]

well, actually you could also put a plug in the open vent in the anker copmartement if you want!

another question:
How much work or how you get the inner cladding in the v-birth to work with the vent pipe (and maybe I want tu put a 220volt cable to the ancer locker to to connect shore power...!)

[BOAT]

I only needed to remove the top layer of foam to run the pipe, and then I used my solder iron with the big plate iron blade on it to melt a small channel in the layer of foam that I exposed. Then I just covered that up with the layer of foam I removed. In the very forward bow nose I just removed the small V shaped hatch the factory put there and removed the foam. Then I ran the hose along the inside of the nose right where starboard and port halves of the boat join to form the V - up the V to the chain locker. I used marine plumbing - the same stuff they use on a Hunter or a Trojan to pipe the kitchen sink so it's all drain water style plumbing for boats. (Non collapsible hoses and flanged sink drains and such). I just did it like as if it were a sink drain in the chain locker except I put it up high so the chain locker drain would drain the water first before the vent hole. Then I just put the foam back and it was done. The hose was easy.

We don't do much 220 over here in colonies but I realize 220 is the norm in the old world - 220 is much better. I have 120 shore power under the helm seat where it stays dry:



The underside of the helm seat makes a nice place to hang the coiled power cord too.

[Russ]

I was told the concern was that an open vent hole is a potential for a 1000 pounds of water to slosh fore and aft in a heavy sea and pound on the gate valve. They said an air bubble allows movement even if the air bubble does not move because air is compressible. I know - they did not have the time to explain it to me. I went again to the Naval books for an explanation of what the factory was trying to tell me. Basic Submarine fundamentals: Water in not compressible, so by eliminating all the air from the tank you eliminate the amount of space in which the water can move. Because water is not compressible it will only move into a void where there is air - which IS compressible. The least amount of air you leave in the tank, the least amount of SPACE the water can compress and displace, and thus the least amount the water can MOVE. If you have a large air space in the tank, the water can compress that air and move right in - back and forth - sloshing like a wave. The wave pounds on your gate valve. Now - the hole is small, so the displacement can only occur as fast as the hole can drain the tank so it's not a big deal in most cases - but over a long period of time, (like in a storm), if enough water is forced out the vent hole the airspace in the tank becomes large enough for the water to 'shift'. In the case of a fore aft shift, it could be quite a pounding. In a normal situation you just open the gate and let the water back in but in a storm?? It's not that easy. Opening the gate in a 20 foot sea could lose more water than gain. I like the bowl open so if water gets into the bowl the water can drain back into the tank, but mostly I wanted to be able to see into the hole when underway. (I also went to a MUCH larger hose and valve so the tank drains just as fast as it did when there was no hose at all).

I'm not sure the "factory" knows much about this stuff. After visiting the Hunter factory and Silverton factory I came to the realization that boat building is not as sophisticated as I thought.

Couple of points:

If the goal is to eliminate air pockets, you have created one with your hatch. Under that hatch is an air chamber that will allow air to compress and therefore water to move in the ballast tank.


I don't think a little air is a big problem. Temps make the tank expand and contract. Perhaps a little air is good to take up this expansion.

The gate valve is a standard RV waste water gate valve. Don't RVs travel on the road? Don't their tanks slosh around and have thousands of pounds of waste water bashing against the valve when they hit the brakes, go uphill or accelerate?

The full force of a tank of liquid is not applied to a filler hole. I bet a hydraulic engineer could explain it better. If you put a hole in a large can and slosh the can, the full force of the liquid is not hitting the hole. You can hold your finger over the hole and not lose liquid. However if you took the lid off, it would be more force. The small gate valve can't be taking that much bashing. I think expansion pressure is more likely a problem. My bet is that RVs vent their tanks and are not air tight like our boats with sealed vents.

I've never heard of a gate valve coming loose or pulling off. Most failures reported here have been seizing up and not opening.

Nevertheless, your setup is quite impressive. The visual inspection is nice. I believe the valve is unnecessary, but very cool. However, if I mod mine, it will be to simply vent it to the anchor locker as others have done. The more I think about it, the more a constant vented ballast tank makes more sense. Allows for expansion. The key is to rock the boat around to burp all air before closing the aft gate valve.

--Russ

[Russ]

(and maybe I want tu put a 220volt cable to the ancer locker to to connect shore power...!)

Remember, the anchor locker gets wet. Lots of water and moisture in there. Electrical connections and water are not good.


--Russ

[BOAT]

Everything you say is true except the part on the RV gate valve. They do blow all the time. The RV will have crap dripping out of it because of an accident - the screws holding the gate can strip because even on the RV's the gate frame is just plastic. If it were metal is would corrode away in a few months. You think salt water is corrosive? You should see what crap can do. I have had many RV's and even my current Sprinter tow vehicle is on it's second gate valve.

As for the factory - no one, (and I mean NO ONE) short of the Electric Boat Company knows more about water ballast in small fiberglass boats than Roger MacGregor. He has been doing it the most, and longer than anyone. He has tried more variations on the vent valve than anyone has ever thought of. He has more boats on the water with water ballast than anyone in the world except, as I said, Electric Boat Company of Groton, Connecticut, and his current 70 footer uses water ballast that can be MOVED. I think if you were going to ask about water ballast who would be better to ask?? You got a better person to call? HUNTER is a late comer to this technology, why would I even consider them? Your just bringing out the troll in me now. And besides, I got no bad comments from the factory about the vent hose so your good, EXCEPT IN A STORM: The manual is pretty clear that the hole must be plugged.

I find the ballast tank in the MAC M to actually more than sophisticated, I would call it very EVOLVED - The rear channels are like ribs that create super strength in the tank sides and the entire lower bottom of the boat is essentially "double hull" because of the tank layout - by putting the forward part of the tank in the deep V hull it makes that part of the tank very large and puts good weight right before the mast where it's needed. The "double hull" type tank makes the boat hull very strong but lighter. I see many years of 'trial and error' when I look at the ballast tank on an M boat. It's engineered by experience more than anything else.

Still, your opinions are more accepted and more numerous than my opinion so I would not argue with you. About the only people that do agree with me about the M boat are the people at the factory. Most everyone I talk to is so ingrained in the old boat building traditions that it's pointless to discuss any other production method than the ones that have always been used before. It's not an issue to debate here as too many have already gone before. No one will ever agree with me that the MAC M is a "well engineered" boat.

In most sailing situations I can just leave the valve open (as the switch was open in the picture) because on that sailing day I was transitioning from power to sail a lot - (it was a crappy sailing day up until the afternoon). That's why the hatch was all wet - I was blowing the ballast to get on a better plane and then flooding it later when the wind came back. And yet, I STILL KEEP THE OLD BRASS FACTORY RUBBER PLUG handy! (just in case). In a storm, I want that hole plugged - and plugging the hole at the top of the bowl instead of at the bottom of the bow was the only way I could figure out how to plug it if I wanted to do it from the helm. You are very correct that 99% of us don't need such a thing. I agree with that.

[Russ]

Don't get me wrong. I believe MacGregor knows a lot about ballast and I agree that the design is well tested and engineered. The safety record proves that. You NEVER EVER hear of a ballast tank leaking despite the many false alarms. The company has come a long way from a Stanford University MBA class project.

It's the little things that I feel boat builders don't know much about. When you look at the things that fail and those that don't. How many have bent spreaders? How many have blown a gate valve?
With all the modded boats with open vents, I've not heard of a gate valve pulling loose and I've been on this forum for 7 years now. Plenty get stuck or have rubber gaskets leak.

This continues with Laura's Tattoo boats. She feels strongly against stern rail seats and doesn't offer them. Yet those of us with them love them so much. I wouldn't sit in them while motoring in rough seas.

I need an engineer to chime in. I just don't see water sloshing around as a big concern to the gate valve. But hey, I'm no hydraulic engineer.
As for your setup, being extra careful is never a bad idea. The benefit of the inspection port is a good one.

[BOAT]

I agree with everything you say and I also agree with Laura - that's why I have never put stern rail seats on 'boat' and I never will. I also never put more than six people on board for the same reason.
I don't think the danger of water ballast is in the system that MacGregor designed - you right - the boat holds it's water with all I can find but a flawless record - that should pretty much end the discussion about their method. The great thing about the MAC is that even if the ballast tank fails by catastrophic reason (hull breach or gate valve failure) the boat still floats just fine and is easy to maneuver back home as long as it's not overloaded. The REAL issue of water ballast is it's center of gravity is so high it creates a righting moment type of performance that most keel boat sailors are not accustomed to and they get scared off the design on the first sail in heavy conditions. They don't trust the ballast because it takes so long to 'kick in', but we have all become used to it and any MAC M owner who has sailed 15 to 20 knot winds a few times has already seen the boat go to 40 degrees and just STOP heeling right there no matter how hard the wind blows. We M owners are used to it, it slows us down but it's not a panic to us. On a keel boat people get really scared at that angle. All the MAC X incidents that have occurred were because of an unballasted boat ending up on it's side, I still don't know if there are any M incidents, but if there were I assume the reason would be the same. Maybe someone with good research skills can get us all the data on every MAC M boat that has ever capsized or been lost and the reasons. I would like to know.

[Russ]

Maybe someone with good research skills can get us all the data on every MAC M boat that has ever capsized or been lost and the reasons. I would like to know.

Yea, I've seen an X on her side for lack of ballast when an inflatable dinghy caught in the rigging pulled it over. There was that overloaded S/D a few years ago in San Diego that capsized. http://www.huffingtonpost.com/2011/03/2 ... 42202.html
You just don't hear about these boats capsizing with normal use. Says a lot for a safe design.

The biggest tragedy was that X in 2002 where the captain was drunk, ran without ballast and had 12 people onboard when he decided to open the throttle.
Sad indeed, but not a problem with boat design.
http://www.ne-ts.com/ar/ar-407capsize.html

[kurz]

(and maybe I want tu put a 220volt cable to the ancer locker to to connect shore power...!)

Remember, the anchor locker gets wet. Lots of water and moisture in there. Electrical connections and water are not good.
--Russ

Well it is sheltered from direct water. And if I put the shore powert under the helmseat I had to put the cable along the side of the whole boat.

So I have no better idea til now, we'll see...