Water Tank Hook Up

So the previous owner installed a water tank, well not fully, it's in the boat just not hooked up to anything. I was thinking of using it more as a ballast since the starboard fuel tank has never been hooked up and running at a gallon an hour I don't really have a use for it. Thus 150 gallons of fuel sitting on one side of the boat creates a bit of a list.

My questions are:

1) Is there an efficient way to create a new deck fill to fill the tank?

2) I don't want to use a thru hull just above the water line with a pump for a drain, would there be a better way to drain it without a thru hull and pump?

3) The tanks been sitting for a few years so may have to be cleaned out, what product do you suggest to do so?

4) Should I also put in a vent since there will water sitting for a period of time?
It's a 36 foot Marine Trader.

Thanks!

1) Is there an efficient way to create a new deck fill to fill the tank?

AN 1 1/2 hole and a deck fill is easy enough and has the advantage that when filling with a hose ant excess simply runs doen the deck.

2) I don't want to use a thru hull just above the water line with a pump for a drain, would there be a better way to drain it without a thru hull and pump?

Most water tanks are not emptied except by using the water.

3) The tanks been sitting for a few years so may have to be cleaned out, what product do you suggest to do so?

Chlorox , in the files 100 times at least.

4) Should I also put in a vent since there will water sitting for a period of time?

The vent is required so the water can be pumped out of the tank with out forming a vacuum and collapsing the tank

It's a 36 foot Marine Trader. " up and running at a gallon an hour",

Congrats!!! you have the most efficient MT made on the planet!!

What FF said and additionally: Can you not use it for its intended purpose and pipe it to the suction side of the existing fresh water pump?

I would run an internal fill pipe from pressure water rather than a deck fill unless more inconvenient.


Run a new vent (can be vented anywhere... overflow should drain overboard but not necessarily a thru-hull) and connection to water system.


Just let it drain to the bilge...fresh water and the few times done a year not a big deal.


Sanitizing also not a big deal...there are multiple methods described on the net.


All pretty easy unless so buried and no need for it (hard to believe if ever cruising).

kyle911 said:

So the previous owner installed a water tank, well not fully, it's in the boat just not hooked up to anything. I was thinking of using it more as a ballast since the starboard fuel tank has never been hooked up and running at a gallon an hour I don't really have a use for it. Thus 150 gallons of fuel sitting on one side of the boat creates a bit of a list.

My questions are:

1) Is there an efficient way to create a new deck fill to fill the tank?

2) I don't want to use a thru hull just above the water line with a pump for a drain, would there be a better way to drain it without a thru hull and pump?

3) The tanks been sitting for a few years so may have to be cleaned out, what product do you suggest to do so?

4) Should I also put in a vent since there will water sitting for a period of time?
It's a 36 foot Marine Trader.

Thanks!

Click to expand...

What did you do, buy a kit boat?

You have an extra fuel tank but it's empty and not hooked up? Hook it up. That way you can balance the boat by drawing fuel from both tanks equally. Adding a tank full of water as "ballast" won't work unless you have a way of filling and emptying it to match the weight of the fuel in the fuel tank.

If you don't need the extra water tank for water, remove it or leave it be. You can add a deck fill if you want to use it for its intended purpose but you must connect a vent. Otherwise you'll have trouble getting water in and out of the tank.

You don't drain a water tank overboard, you drain it into the bilge or you just run water in a sink until the tank is empty.

The tank may be abandoned for a reason.

Thanks for the help!

I have no need for a second fuel tank since the only cruising I do is about twice a year, eventually the fuel would just go bad. Plus at a gallon an hour even if I cruise more that's about 300 hours of cruising. I'm up in Canada so to do 300 hours in a season is a lot! Good but would never cruise that much yet.

On top of that one day I may decide to hook the second tank up, it wouldn't be a problem and then I would just re route the water holding to my actual taps. Also not to mention the price and time to clean the actual fuel tank since it's been out of service for many years.

As far as if the tank actually hold water, I don't know but I plan to do a crash test before hooking anything up.

Thanks again for the help.

Greetings,
Mr. 911. "I have no need for a second fuel tank...". In fact, I think you do. Your boat is listing (slightly). As mentioned, using a water tank to offset your active tank is a pretty mickey mouse way of straightening up.

It might be quite simple to scope out your unused tank, analyze any potential problems, rectify them and begin using that tank and walla! No more list.

kyle911 said:

Thanks for the help!

I have no need for a second fuel tank since the only cruising I do is about twice a year, eventually the fuel would just go bad. Plus at a gallon an hour even if I cruise more that's about 300 hours of cruising. I'm up in Canada so to do 300 hours in a season is a lot! Good but would never cruise that much yet..

Click to expand...

You don't have to fill the tank full.

Please go back and read what I posted about using a water tank as ballast. Then think about it.

WesK said:

You don't have to fill the tank full.

Please go back and read what I posted about using a water tank as ballast. Then think about it.

Click to expand...

Even still I don't find a use for a second tank for the amount of time and money it may take to get hooked up. Like I said it has been sitting for years so I could be dealing with rust, it maybe a dud either way. I will have to scope it out before hand and see what my best options are.

As I understand past postings you do not want to put any kind of bleach water treatment in an aluminum water tank.

Hello Kyle911, I have a MT 36 as well, and We are right around the corner from you in Buffalo NY. My boat has 4 water tanks in the stern, all connected with tubing. Holds about 200 gal. It also has twin fuel tanks , one one each side. I can see how your boat would list if one was empty.
Couple of thoughts here to consider. An easy and inexpensive way to check your empty tank is to use water and fill it up. Check for leaks. Why water? Sounds crazy right. Well call a marina that cleans tanks and you will see that is how they do it. They flush with water and then a bit of diesel. Let it dry, add a water remover additive and you should be good to go. It may take some foresight to plan on how to drain the water, my tanks have a 1 1/2 inch drain plug at the bottom of the tank.
You can determine if the tank is sound, then run both tanks. I run both tanks at the same time to balance the weight.
I have a question for you: does your boat have lead ballast in the stern? Mine has lead ballast attached with resin on either side of the rudder post way back in the stern on the bottom of the lazerette.
I have been trying to determine if this is from the factory or added later.
Hope to meet up with you some time!

Do not let lead ballast come in contact with anything Al like water or fuel tanks. Result is rapid corrosion.

X24 said:

Hello Kyle911, I have a MT 36 as well, and We are right around the corner from you in Buffalo NY. My boat has 4 water tanks in the stern, all connected with tubing. Holds about 200 gal. It also has twin fuel tanks , one one each side. I can see how your boat would list if one was empty.
Couple of thoughts here to consider. An easy and inexpensive way to check your empty tank is to use water and fill it up. Check for leaks. Why water? Sounds crazy right. Well call a marina that cleans tanks and you will see that is how they do it. They flush with water and then a bit of diesel. Let it dry, add a water remover additive and you should be good to go. It may take some foresight to plan on how to drain the water, my tanks have a 1 1/2 inch drain plug at the bottom of the tank.
You can determine if the tank is sound, then run both tanks. I run both tanks at the same time to balance the weight.
I have a question for you: does your boat have lead ballast in the stern? Mine has lead ballast attached with resin on either side of the rudder post way back in the stern on the bottom of the lazerette.
I have been trying to determine if this is from the factory or added later.
Hope to meet up with you some time!

Click to expand...

Thanks for the info!! There is no ballast at the stern, although this could have been removed by previous owners. I knew both the original owner and the one after him (we all lived in the same marina for awhile). Neither of them mentioned a ballast.

Kyle, FWIW, and I have a similar vessel, and I have both the fuel tanks and two water tanks linked by T-junctions so they drain evenly, (and from the bottom, with no pick-up tube down from the top - a good arrangement, because stuff can't accumulate on the bottom), so there's never a trim/list issue.

We don't do large mileages or cruise a lot either, but you can never have too much water in our experience, and water in tanks does not 'go off' anyway. Also, and relevant to your situation, we never, repeat never, have filled our fuel tanks, as we never need that much, and I also don't want it to get too old, and I have to say we have never had any issues with water from condensation etc, and I believe it is an issue grossly overstated.

However, looking forward to the time you might want to sell, having only one fuel tank, and one water tank would be a turn off, especially if it creates trim issues. Looks awful even if not a safety factor. Creating a water deck-fill is easy, all you need is a decent hole saw of the correct size and appropriately sized piping, and the threaded opening and cap - easily obtained.

If your tanks are linked you can fill them from the one side, so if you linked the extra water tank to the other, (you must have one, surely), you may not need another deck fill - same for the unused fuel tank. Just the top air breather vent. It just takes a bit longer to fill, that's all. Most tanks come with an air breather built into their top anyway, and the water one can just vent into the bilge, have you checked..?

Oh, and yes, coming back to the comment FF made above re efficiency...unless you have a very unusual engine in her, she will consume more like 2 gal per hour at 7 knots. Just sayin'...

He might be tooling around at 5 knots.

As to your tanks. Do the person who will end up with your boat a favor and set it up the way it was meant to be configured.