MacGregorSailors.com

I see from searching the forums that others have had the same problem as I with the bad smell coming from the ballast tank when the vent plug is open. It seems most solve this problem by adding bleach or chlorine to the tank.

My question is... has anyone inspected their transom valve seal after using the bleach or chlorine for a year or two to see if there is any degradation?

Kelly

With six seasons use I have no degradation at all.

Second season with ballast in. Have used chlroine tabs and no visible signs of a cracked seal.

Compromise wrote:Second season with ballast in. Have used chlroine tabs and no visible signs of a cracked seal.

Just curious, what size tabs do you use? I'd assume the 1" (don't know if there are any smaller) How many do you use? What frequency do you add them? Just bought my first water ballasted Mac (26X) and want to keep it looking and running nice as long as my old swing keel Mac.

Thanks

to keep the bilge storage area smelling nice I have a small plastic container drilled with holes keep about 6 cedar mothballs in it, gives off a nice wood cedar odor

John

I notice that I am starting to get some odors too. Would the treatment used to sanitize porta-pottis do anything? It has a more pleasant smell than chlorine.

I am a hydroponic grower and I have learnt over the years to treat water.
I have to do it all the time. I use chlorine every day of my life.

Chlorine is corrosive, so do not over-dose.

For the ballast, there is really only one solution....chrloine. You need to sanitize the water, not make it smell nice. It is the bugs that grow in the water that will give off odors and create growth problems for you.

Never mix any form of Chlorine with any other chemical....that is very dangerous. Chlorine is a hazardous product, but in a solution of water at levels found in swimming pools or your drinking water there is no danger.

So if you are using the liquid chlorine, be careful not to spill it on your self (wash off) and avoid fumes. If using tablets, read the label. Always use your brains and common sence and you will be fine.

Liquid chlorine has between 10-15% available chlorine. Most public pools have min 1ppm (part per million) chrloine, and that works just fine. So for the ballast, calculate the amount of water, convert to metric (litres) and for every thousand litres add 10-15millilitres of chrloine to get 1ppm free chlorine. So you don't really need very much. It will get used up so dose frequently. buy from pool shops.


Tablets: Trichlor is a tablet (stabilized- dosn't break down so quickly in sun etc) form of chlorine, and has 90% (check your label) available chlorine. Slow dissolving, and works well in floaters.

I never 'throw' one in to a tank as they can etch all sorts of materials. That is why I always use floaters. Biggest problem you will have is unknowinly getting it on your fingers, then wiping your hands on your shirt/trousers....bingo.....bleaches material white, then rots out....really quickly.

I have to ask the question...when you take your boat out, why not drop the water out of the ballast, then refill with 'new' water.

Don't ever be scared of chlorine.....it is probably the most important chemical to mankind......as it gives us 'clean' water.

Cheers
Phillip

Phillip wrote: ... Tablets: Trichlor is a tablet (stabilized- dosn't break down so quickly in sun etc) form of chlorine, and has 90% (check your label) available chlorine. Slow dissolving, and works well in floaters.

I never 'throw' one in to a tank as they can etch all sorts of materials. That is why I always use floaters...

Phillip,
Lots of good info there. When you wrote "etch all sorts of materials" you were obviously referring to the fiberglass hull bottom, right? So it sounds as if a 'floater' could become an 'etcher' if I drained the tank while a partial tablet was still floating? So, it seems liquid Chlorine would be a better choice!

Since many of us in the USA are "metrically challenged," I became curoius about relating our common gallon of Clorox household bleach (128 ounces) to my 200-gallon ballast tank (26X). Clorox is a 5 to 6 percent solution of sodium hypochlorite.

I started out guessing ... just to scale the problem for amusement, assuming a 1% ratio of free chlorine ... how much Clorox would I need? Assuming it contains 1% free chlorine, I calculated about 2 ounces of Clorox to bring the ballast tank ratio to 1 ppm. (Two ounces is just a double shot glass to many of us!) Intuitively, that seems far too small an amount.

HOWEVER, the website quoted below just totally blew away my musings. They purport that a gallon of Clorox would treat 60,000 gallons (300 X-boats) to that magic rate of 1 ppm~!!! That's not a shot, not a whiff, barely even a sniff! I'm thinkin', "Nah ... that simply cannot be correct!"

[u]Website Link[/u] wrote: ... Chlorine is chlorine, so the chlorine in bleach is the same as the chlorine in drinking water and in a swimming pool. In fact, you can use chlorine bleach to treat a swimming pool or to treat drinking water. A gallon of bleach provides 1 part per million (PPM) of chlorine to 60,000 gallons (about 250,000 liters) of water. Typically, a pool is treated at a rate of 3 PPM, and drinking water is treated at anywhere from 0.2 PPM to 3 PPM depending on the level of contamination and the contact time.

[b][u]Wikipedia[/u][/b] wrote: (In the USA)
Double shot glass-- 2.0 fluid oz. ˜ 60 mL

Frank:

etching:

I don't know what chlorine does to fibreglass.
I do know that in my dosing dispenser it wears away the heavy duty plastic pipes and fittings which are of commercial irrigation grade. Because of this, I never ever put the tablets in my 2 large plastic tanks nor the fibreglass one unless they are in a floater, and I have never had one settle on the bottom as the floater is on the end of a string, tied to the tank.
When you have $20K of tanks and fittings, I'm not taking the risk.

I do know it is very corrosive to many materials and metals.
As for fibreglass, I don't know.


Frank, this is what I use to convert everything.
http://joshmadison.com/software/convert/

Not sure how I did it, but I have it on my screen continually.

Here is another site that is easy to use too.
http://www.onlineconversion.com/

I understand the difficulty in calculating ppm(parts per million).

1 part per million means that if you have 1 million things (liters, gallons, eggs, slices of bread etc.) 1 of those will be what you need.

and for you people, the easiest way to calculate how much chlorine to use; then use such a converter to
1. convert your gallons to litres

2. for every 1,000 litres of water (1 million millilitres) you need 1ml(millilitre) of chlorine to get 1ppm.

3. as you need 1ppm 'free chlorine' to treat the water, you have to work out (ask or read the label) how concentrated the chlorine really is.
If the liquid chlorine is 10%, then you need 10mls of chlorine to get 1ppm free chlorine to sanitizing 1,000L.

10ml (milliliters),would give you 1ppm free chlorine in 1,000 Litres (one cubic meter).


Remember that chlorine evaporates fast so expect to have to add some chlorine regularly.

Remember they may recomment 1ppm free chlorine, but 2ppm won't do any damage, it is just a waste of chlorine. So try and be as accurate as you can, but don't worry if you go over a little.


This is how I understand Chlorine to work.
When chlorine is added to water, it kills microorganisms by slashing through the cell walls and destroying the inner enzymes, structures and processes.
Just like a bolt of lightning.
When this occurs, the cell has been deactivated, or oxidized.
The hypochlorous molecule continues this slash & burn until it combines with a nitrogen or ammonia compound, becoming a chloramine, or it is broken down into its component atoms, becoming de-activated itself.

Not sure if you have noticed, but after you add chlorine, you often smell a really strong chlorine 'odor'.
I understand this to be 'chloromine' which is formed when the chlorine has finished deactivating 'badies' or comes in contact with nitrogen and amonia (eg fertilizers or urine).

It may seem complicated but it isn't.
What we should do is put together a simple chart for everybody, so all they have to do is read off the required 'dose' of the different products.

I just don't know how many gallons or litres are in a X or an M.

Cheers
Phillip

Not sure if you have noticed, but after you add chlorine, you often smell a really strong chlorine 'odor'.
I understand this to be 'chloromine' which is formed when the chlorine has finished deactivating 'badies' or comes in contact with nitrogen and amonia (eg fertilizers or urine).

Correct. When the pool is clean, you wont smell anything. The only (homeowner) way to test the hypochlorite concentration is with test strips which you can get at any hardware store. When you go into a pool and 'smell chlorine' its the chloramines you actually smell -the result of the chlorine acting on all that biological stuff the kids did in the pool

Avoid hotel pools like the plague....literally.

One of the reasons I love this board is the variety of skill sets/knowledge/experience that acummulates at the table. Who'd a thunk we would have a water treatment "expert" here? To answer your question Phillip, I do not keep the water in the tank... my boat lives on its trailer at the marina and my trips are usually from 1 to 3 days long. Once I launch, I fill the tanks and dont empty until I return (with my daughter on board I refuse to use the boat with an empty tank). When I first got the boat (new), I took 2 daysails in fairly quick succession and it was at the end of the second I noticed the smell, so I know my problem is not one caused by growth over an extended time. I guess there is something in the water of my marina that just "loves" ballast tank conditions.

I am not aware of a specification for the M which lists the volume of the ballast tank. From the Macgregor website, describing the M...

After launching, the transom valve is opened and a tank in the bottom of the hull is gravity filled with 1150 lbs of sea water

A pound of fresh water is 0.12 US gallons so we can calculate a volume of 1150*0.12 or 138 US gallons (my research has indicated that the difference in densities between fresh and surface sea water is not enough to make a significant difference at the quantities we are talking about)

Phillip suggests 1PPM... 138 gallons is 523 liters (138*3.79), divide that by a million and the requirement would be 0.000523 liters of chlorine. The label of Clorox regular bleach states that it has 5.7% available chlorine. That means that to get 1 liter of usable chlorine you would need 100/5.7 liters of clorox which works out to 17.5 liters, so 0.000523 liters of chlorine (the requirement) would be 17.5*0.000523 or 0.009 liters of clorox... approximately 10 milliliters or 0.338 US liquid oz. ( 10 ml/1000*33.8 )

Frank's web source indicated an upper limit of 3PPM, so if 10 ml. (or a third of an ounce) is 1PPM you get 30 ml. or 1 liquid US oz. as the measure they recommend. I cant find a flaw in the math! The question in my mind is... are these concentrations (1-3PPM) optimum for cleaning the tank or are they optimum for making the water potable. For the ballast tank our only concerns are corrosiveness on the fiberglass and transom valve, fumes that may come up through the vent plug and kindness to the environment when the tank is dumped.

My reaction is the same as Frank's... 1 oz. seems awfully little.

Kelly

Edited to clarify weight vs. volume calculations
Second edit... changed units from US Gallons/ounces to liters

I didnt see this explicit in your calc but were you possibly mixing up fluid ounces (volume) iwth ounces of mass. It looked like you were using ounces of mass thoughout, but Im just checking.

1 ppm is not a high concentration - and is actually roughly the correct value of free chlorine for drinking water...much lower than the fiberglass damage threshold, Im sure. When you add a chlorine source to a water supply, the first thing that happens is it reacts with all the organics making chloramines...this soaks up the chlorine until all the bad guys are gone. In a funky ballast tank, you might need a lot more than an ounce of bleach to kill the organics before you get any free chlorine.

The effectiveness of chlorine as a disinfectant is highly pH (acid level) dependent btw...also, chlorine disinfectant can take up to a week to kill the really bad guys like chrys. and friends...

Interesting point. I was using volume ounces (the only mass calculation was to use the known weight of ballast to estimate the volume of the holding tank, and thus the water it contains) and I really hadnt considered weight. Now that you bring it up, weight would seem to be a more accurate and scientific way to do the calculations. I could check the weight of Clorox, but I am not sure how much use that would be because what I really need is the weight of the active ingredient (Sodium Hydrochorite) rather than of the entire solution.

I dont really know where to go from here other than to wing it. I am thinking of using a pint or so of bleach to "shock" the tank and get rid of the existing gunk (The first time I launched this year the smell was there even after a 5 month layoff), then use maybe a half cup each time thereafter for maintenance.

Kelly

I only have a few minutes free at the moment.
If I may suggest, convert your gallons to litres and then do the calculation.
You may find it about 1 million times easier!!!!
It is all just a matter of norts..
Cheers
Phillip

That only works, Phillip, if for the end-game ....
I know precisely what _xxx_ milliliters looks like for measuring!

and I don't~!


How many shotglasses in _xxx_ milliliters ... hmmm??