MacGregorSailors.com

I would think that the inside of the ballast tank would be very full of rough & sharp edges even worse than whats in the bilge , to much chance of cross contamination & who wants too take that chance of getting sick on a cruise or vactaion
would require way too much maintenance on a reg basis for health & hygiene reasons, way to complicated for what it does for absolutely no reason , u r creating unnecessary required maint. schedules when their is a lot other better ways to store water with a lot less required maint.
Plus u r making a mod that could create a dangerous situation if something should go wrong that u most likely would not be aware of until something happens

just my 2 cents worth to each their own !

J

I've thought about ways of using the ballast tank as fresh water storage. My final conclusion is to fill the ballast tank with fresh water when first put in. You also have 30 gallons or so of fresh water in the V-Berth. After you have emptied the V-Berth, you refill it by pumping and filtering water from the ballast tank, then refill the ballast tank with raw water.

This gives you twice the usable fresh water of the V-berth storage.

Note: It's your bathing water only. Your drinking water is kept separate.

Stevenhigbee wrote: You also have 30 gallons or so of fresh water in the V-Berth. After you have emptied the V-Berth, you refill it by pumping and filtering water from the ballast tank, then refill the ballast tank with raw water.

This gives you twice the usable fresh water of the V-berth storage.

This wouldn't actually be fresh water. It would be brackish water.

For bathing, I have a washdown pump with an intake hose over the side with a filter attached. Cheep RV filter takes out most crud.

I've talked about putting a ball-valve on the opposite side of the gate valve on our boat so that the ballast tanks fill inherently and remain full of water whenever the boat is in the water. The gate valve would then only be used to dump water at the ramp. This would make the boats inherently ballasted, and I think it should have been how they were designed. Owners who want to run empty while motoring would have to manually cover the ball valve.

Anyway, a ball-valve would solve your ballasting problem as you use fresh water from a bladder inside the tank.

We've always just packed the bilge with 16oz water bottles for trips, which we still do on the big boat. You can carry quite a bit of drinking water safely this way.

After looking over the ballast gate valve and the aft of the ballast tank, I'm not too sure I could reasonably pull 3" discharge tube through it. If not, That doesn't rule out the concept, as I am considering enlarging the front vent to 2.5" or 3" which would be plenty of room to drop in the tube. I did a bit of testing with a short piece of discharge tube, using pvc cement to glue the ends and then hose clamped, one closed and the other with a brass hose barb, it held pretty well but blew out after I hooked it up to house water pressure. 50 psi was probably excessive and would probably blow out a commercial flexible water bladder, I'll retest with less pressure.
I'll probably try a test of the tube just laying it along the floor tucked next to the ballast plumbing without inserting it into the ballast tank, just to make sure the concept will work. This might wind up to be a good approach in any event, because that space is not utilized, although it will not serve to minimize weight.
I am not concerned about having a very slightly less than full ballast tank at times, being down a gallon or two I don't think will make any difference to boat safety, dangerous sloshing is going to occur with something like a half full tank, where the water has enough space to really slosh from one side to the other. Also, I doubt it would be non full most of the time, water use will occur most often when not sailing, so we would just top up the ballast before each sail. If one were still really concerned about having a ballast tank not completely full after using a few gallons without cracking the ballast valve, then just use the sausage water to top off a conventional water jug connected to the galley.

I don't think maintenance of the tube will be any different from a conventional bladder other than access. However, one would need to be able to detect leaks somehow. I am thinking just introducing food coloring into the full bladder with an empty ballast tank, and checking what comes out of the ballast valve. If any colored water came out of the ballast then one has a leak, otherwise it is good. But one would want to be able to pull the sausage out without too much difficulty.

If I did drop the tubing through the front vent rather than the gate valve, a thin stiff perforated inner tube in the sausage would be important to allow flow through the sausage even when folded over on itself. I would not worry about this sausage tube pile moving around for boat safety with an empty ballast tank, I do not think it would be able to move easily, and even if it did move with heeling, it would not move far or fast or slosh. In fact, it would act more like internal baffles to minimize sloshing when the tank is filling or emptying. But it would be easy to evaluate, just check for changes to boat trim not explained by other factors.
The 3" tube is designed for potable water, although not necessarily for storage of potable water, so it might import a plastic flavor if stored long but shouldn't be toxic otherwise. It can be rolled up into less than 2" diameter to get it into or out of an enlarged ballast vent hole.

Well as I just installed an automatic ballast vent in the bow I came to the following idea:

Why not glue some openings directly into the ballast tank (e.g. like in the bow)


They go til 24cm openings.
So you could put a big one to bring in the tank bladder.

An some more mount some strong holding points for the bladder.

so some plus for this mod:
through the openings you can anytime have a real good control.

you can use standard water bladders.

You can take out the bladder any time you want or have to. No need to go out of the water with the boat.

If you empty the ballast tank and also the blather it will stay safe in the ballast water tank.

kurz wrote:Well as I just installed an automatic ballast vent in the bow I came to the following idea:

Why not glue some openings directly into the ballast tank (e.g. like in the bow)


They go til 24cm openings.
So you could put a big one to bring in the tank bladder.

An some more mount some strong holding points for the bladder.

so some plus for this mod:
through the openings you can anytime have a real good control.

you can use standard water bladders.

You can take out the bladder any time you want or have to. No need to go out of the water with the boat.

If you empty the ballast tank and also the blather it will stay safe in the ballast water tank.

Just one thing wrong with that idea !! if u r going to do sh-t like that for insurance purposes u better make sure what u r using is designed & approved for what u r using it for , these r for deck & access plates , they r not design for taking internal pressure against them the bigger they r the more pressure will be on them & more likely to fail u really have to think these mods out especially when it includes something involving a safety factor just saying that's all
J

Your are right Highlander. Any change to the ballast tank could make big problems with insurances of course!

I dont know how much pressure the cheap openings can stand and how much pressure we need for the ballast tank.

But my idea goes for a principle. You can buy more expensive service openings that are used for fuel tank etc.

Or you can laminate a rim in the ballast tank then put a seal and put a gfk cover with screws... The principle can be improved easily.

Yeah, I don't think so.

No, you should not put holes in the ballast tank. Let's get real, if it was a regular boat with lead ballast this whole conversation would not even be happening. You need to treat the ballast tank for what it is - it's a dedicated space for ballast - just as much as if it were full of lead as opposed to water.

If you are in such a hurry to replace ballast water with a fresh water tank just ask yourself: If you owned a 'normal' sailboat would you be in a hurry to tear out lead ballast to replace it with fresh water tanks?

Probably not.

Yea, I wouldn't put much faith in this thing being watertight.


Although, on the same note about insurance and holes that don't belong. I would be much more concerned about opening portholes where they can be submerged.

This will capsize your boat in 20 seconds.

I think if you MUST find a place to add more fresh water it would be better to remove flotation and put in a hard sided water tank low in the bow. The safety theory works the same way in reverse without all the harmful effects of a bag flying around inside the ballast tank.

You can remove some foam from the front V berth and put a HARD SIDED water tank there (NOT a BAG). The problem with a bag is that as it empties it does not provide the replacement flotation that the hard sided tank does when it is empty. An empty water tank provides as much flotation as the same volume in foam - so I would rather see people replace their foam with water tanks than their ballast if it's absolutely necessary to do so.

And to make sure I don't get in trouble with Kevin i must say that it's wrong to remove any of the flotation. I would see this as an emergency thing - like your gonna be away from fresh water for weeks and your more likely to die of thirst than sink. In that case: a hard tank replacing flotation for the temporary storage of water would be a better option than using ballast space.

(imo)

If I were to go the route of access to the ballast tank from the vent rather than the transom gate, it would not be through a new hole, but just through slightly enlarging the ballast tank vent hole, from stock 1" to ideally 3" or 3.5".
And yes, if that were done one would need to make sure the enlarged hole was stoppered or vented equally to the stock vent hole for reliability and safety. The diameter of the 26m vent hatch is 6" so any vent hole enlarging would be limited to smaller than that. If one is worried about insurance in that regard, then one should not be modifying their vent hole in any regard, not to the anchor locker, not to a valve, nor to any of the many methods discussed on this website. And one should not be removing flotation which is expressly cautioned against all over the manual, but it seems that everyone does it in order to add v berth water or some other mod. In terms of safety, I think v berth water tanks either hard sided or flexible is more risky than an enlarged vent hole, as once that foam is removed the boat is at risk of sinking (also the case with a full hard sided tank). Whatever could happen with an enlarged ballast vent hole is exactly what could happen with a small stock vent hole, just faster. If I were doing it, I would obviously retain the overflow cone above the vent which provides some means of avoiding flooding if the stopper failed or were forgotten.
One bonus to slightly enlarging the vent hole is being able to manually pump out water, such as if grounded which has been discussed before.
I tend to run with a full ballast tank which makes any motion of a bladder in the ballast irrelevant. But I agree their is increased risk if running without water ballast from a potentially moving bladder in the ballast. That potential risk does favor pulling the sausage though the transom thus confining it at both ends and confining it to the narrow ballast channels. I still have a long way to go to test, but if I get to the point of not being able to pull it through the transom gate valve, I may just keep it outside the ballast and run it along the bilge floor confined against the ballast channel and leave the vent hole stock.

But I have not yet given up on a transom gate valve access design. Thanks everyone to the good feedback.

Flightfollowing wrote: In terms of safety, I think v berth water tanks either hard sided or flexible is more risky than an enlarged vent hole, as once that foam is removed the boat is at risk of sinking

Simply removing flotation doesn't put the boat at risk of sinking. You have to put a hole in the boat or somehow fill it with water before that happens.
Quite frankly, I've been looking for a report of one of these boats getting a hole or swamping to the point of the flotation was engaged. Haven't really found one. The design of the Mac makes it pretty hard to capsize, even if turned over,water can't get in the companionway. With the majority of Mac owners being noobies, you'd expect more reports of capsizing. I credit a safe design. These boats, when not overloaded, simply don't get anywhere near sinking.

Whatever could happen with an enlarged ballast vent hole is exactly what could happen with a small stock vent hole, just faster.

I think that's the concern. Water gushing in through a 3" hole can fill a boat quickly. However, if the gate valve is closed and sealed, only the ballast water can enter the boat. It's already in the boat, so it wouldn't add extra water, just make a sloshy mess and cause the boat to be less stable like with a partially filled ballast tank.

One bonus to slightly enlarging the vent hole is being able to manually pump out water, such as if grounded which has been discussed before.

I'm always amazed at how much higher the boat sits with the ballast empty.
This past summer, this Catalina 30 captain ran aground on this reef. He had the brilliant idea to pump all his fresh water out to get free. So he pumped out maybe 320 pounds of water with a boat that has 10,000 pounds of displacement. I doubt it lifted the boat a millimeter. Our Macs, however, probably come up 4 inches by emptying ballast.



I think your sausage idea has promise. The hardest part is keeping the thing in place.

Very good points, Russ.
I just managed to push fish tape through the ballast tank to the vent hole and vice versa, it was relatively easy to my surprise. Seems like a straight shot from the gate valve through the port ballast tube, and then it widens up at the daggerboard for about the last 6 feet to the vent hole. The only place the sausage could possibly move or swing inside the ballast tank would be about that 6 foot stretch from vent to daggerboard, and at the daggerboard it would be confined and at the vent it would be confined with the output hose, so the tube would have very very little movement, as long as it can be pulled through the transom valve as per the original concept.
That would be the next hurdle, being able to pull the flat 3" hose through the tank and it being intact when in place, rather than shredded. But I am now optimistic, as the fish tape ran through easy. I don't think an enlarged vent hole will be required in any event. I should probably use a test piece of 3" hose and pull it through the ballast valve to the vent, and then back out and inspect it. It would tell me how much abuse the hose will take and how smooth the ballast tank is. It may also polish the port ballast tank tube to make subsequent hose pulses easier and cleaner.
Sealing the end and inlet of the discharge hose is my current task, if anyone has ideas let me know. Using pvc cement and hose clamps. Tried epoxy which did not bond.

Flightfollowing wrote:Sealing the end and inlet of the discharge hose is my current task, if anyone has ideas let me know. Using pvc cement and hose clamps. Tried epoxy which did not bond.

What is the hose made of?

Could it be heat sealed like baggies are manufactured? Not sure how to do that, but it might work. Heat up some kind of clamp and melt it together?
There are a zillion adhesives out there. Surely something is made to bond with this.

--Russ