Bladder tanks

[boomerang]

As with a lot of smaller boats, storage is an issue, and that's especially true on ours while we're cruising. Another problem is the small 40 gallon water capacity we have. It's just my wife Liz and me & neither of us will entertain the idea of skipping a shower for a day. We both like to shower in the morning and at least rinse off in the evening ,especially after a hot day or a cooling dip in salty or brackish water. I'm content with showering in the cockpit in warm weather and even bought one of those 5 gallon solar camping shower things that will give me 2-3 or more decent rinses.
Anyway, the poly tank that Mainship used takes up a good amount of what would be useable stowage space under the cockpit. I have a plan to put a shelf under the cockpit spanning the 4 longitudinal stringers and lay a flexible bladder tank on the shelf. It will take a minimal amount of plumbing to extend the supply line and fill tube.
Not being familiar with this type of tankage, what are others experience with bladder tanks? I'm most interested in finding out if we'll be able to actually get close to the 50 gallon capacity with a flexible tank or if a lot of the capacity isn't useable due to the design. I know that ,because of the placement of the pickup port in the current tank, we probably only have 35 gallons or less of useable water. Going from a 40 gallon to 50 would be a big deal for us. I guess we really are plebeians because a lot of cruising couples could hardly brush their teeth with the capacity we carry! :lol:

The first 2 pictures are of the area that I'm proposing a shelf be installed for the flex tank. Kindly ignore my swim platform bonding job...it was hot as heck under there so the cables never got fastened.
The next pic is of the current tank & location under the cockpit and lastly ,the 50 gallon bladder tank I want to use.

 

[Solly]

Somehow on my Mainship they shoe horned a 200 gal. fuel tank down there. I think they had to install it b-4 the deck. I'd look at replacing the stock tank with something bigger. That would save running another fill, vent and water line.

On mine the water is outboard on the port side by the engine. Probably where your fuel tanks are. I added another tank behind it plumbed to a 3 way valve.

 

[boomerang]

The reason I'm looking at the Plastimo tank is because A) it'll give us another 20% capacity (in theory) & B) There's only 12-14" of overhead clearance under the cockpit so a conventional tank wont fit and since it's wasted space anyway, I'd like to use it.
I would like to just do away with the existing tank to give us more room to store other junk. Plus, when we rebuilt the salon door (if you're looking, it's SALON, Mr RT Firefly, NOT SALOON! ), I added 2 -2x4 stanchions that run from the 2 inboard stringers up to the underside of the cockpit to support the previously unsupported threshold, so that forced me to move the tank aft at least 6-8".
I'm not worried about the plumbing part. As long as the new flex tank has no problem supplying the pressure pump that's mounted under the cockpit anyway.

 

[HeadMistress]

The average lifespan of even top quality ($$$) bladder tanks is only about 15 years, vs the indefinite lifespan of top quality plastics. Looking at your photos, I'd bet real money that Ronco Plastics has a size and shape that'll be what you want. They make TOP quality thick-walled water and waste tanks for a very reasonable price and have more than 400 shapes and sizes, over 100 of which are non-rectangular, AND they install fittings in the sizes and locations specified by the customer when they make the tank. There are retailers who sell Ronco tanks, but Ronco sells direct for a much lower price...and they're great to work with.


Their current marine catalog is here Ronco Plastics marine Tanks Because so many people have told 'em that their previous catalog is so much easier to search, they left that one up too Ronco Plastics old marine catalog.


As you look for a tank, keep in mind that there's no top or bottom on any of 'em until the fittings go in...and you get to decided where they go. So feel free to rotate 'em, flip 'em end for end...orient 'em any way you want to.



--Peggie

 

[rslifkin]

12 - 14 inches of height shouldn't be an issue for fitting a standard tank. Just have to find one the right shape. My original water tank is only 10 inches tall due to the space it's squeezed into.

 

[HeadMistress]

(if you're looking, it's SALON, Mr RT Firefly, NOT SALOON! ),

He may not be looking but I am...and SALOON is actually the correct term...or was until the mid -1980s when the marine industry decided to market boats to anyone with a pulse and a credit card with high enough limit to make a down payment, few if any of whom had the slightest knowledge of nautical terminology. Till then, the 1st definition of "saloon" in most dictionaries was "any large room or hall designated for receptions, exhibitions, entertainments etc, specifically the main passenger cabin of a passenger ship." In fact it was the first half of that definition that led to drinking establishments being called "saloons."
As "salon" began to replace the correct "saloon" in boat marketing literature (God forbid the marine market would risk offending any buyers or try to educate them), it created quite an uproar among boat owners old enough and literate enough to know the correct term.

Sadly, knowledge of correct nautical terminology has now deteriorated to the point where the nautically illiterate are now correcting those who still use the correct terms.

(Tomorrow's lesson will be on the correct spelling and pronunciation of "gunwale.")

--Peggie

 

[HeadMistress]

You don't want a Plastimo tank, Shawn...they're the least expensive by far for a reason!
If you're determined to go with a bladder, look at Nauta or Vetus. Their prices will make difference in quality obvious.


--Peggie

 

[Blissboat]

Having shoehorned additional, badly-needed fresh water tankage into a couple of sailboats, this is an interesting project. A few brief observations:

Your plan will increase the weight of your fresh water supply by some 83 pounds (10 additional gallons, at 8.33 pounds per gallon). Not a big deal by itself. But, if I understand correctly, you will also be relocating the entire weight of your water supply - 416.5 pounds. You will move it from near the hull bottom and raise it to a point several inches higher, in the stern of the boat.

That by itself, is also probably not a huge deal. But, as boats age, owners invariably add weight to them incrementally, bolting in equipment and other improvements everywhere. It's easier to access and modify areas of a boat that are higher, so that's where additions and modifications tend to find their new homes aboard. The result is that, incrementally and almost unnoticeably, the center of gravity of any boat creeps up over the years. A boat that is stiff and stable on the day it was launched and commissioned will, after a decade or two, often roll with increasing tenderness. It happens to yachts, larger commercial vessels and warships.

History is full of examples where a gradual elevation over time in a vessel's center of gravity combined with other factors, eventually creating a hazardous state of instability waiting to appear at the worst possible moment.

Think about this project holistically, in the context of the entire boat, is all I'm suggesting.

 

[boomerang]

(if you're looking, it's SALON, Mr RT Firefly, NOT SALOON! ),

He may not be looking but I am...and SALOON is actually the correct term...or was until the mid -1980s when the marine industry decided to market boats to anyone with a pulse and a credit card with high enough limit to make a down payment, few if any of whom had the slightest knowledge of nautical terminology. Till then, the 1st definition of "saloon" in most dictionaries was "any large room or hall designated for receptions, exhibitions, entertainments etc, specifically the main passenger cabin of a passenger ship." In fact it was the first half of that definition that led to drinking establishments being called "saloons."
As "salon" began to replace the correct "saloon" in boat marketing literature (God forbid the marine market would risk offending any buyers or try to educate them), it created quite an uproar among boat owners old enough and literate enough to know the correct term.



Sadly, knowledge of correct nautical terminology has now deteriorated to the point where the nautically illiterate are now correcting those who still use the correct terms.

(Tomorrow's lesson will be on the correct spelling and pronunciation of "gunwale.")


--Peggie

:lol:
I know...I'm aware of the definition ...I've already been scolded by Mr RT. I'm sorry to admit it ,but I'm old school too but I cut my boating career teeth working for a Hatteras dealer in the very early 80's. They called it a salon so far be it from me to argue with Mr Slane or AMF or whoever owned them at the time!

 

[HopCar]

I used a bladder tank for black water holding. I eventually replaced it with a plastic tank from Ronco. I like bladder tanks for temporary storage but prefer rigid tanks for permanent installation.

I sold bladder tanks made by Goodyear, Nauta, Plastimo and ATL, ATL was by far the best.

 

[Dwk]

Following. We have the same limited capacity (40galj and want too
add to our existing water supply with either a bladder or Ronco tank.

 

[jleonard]

When I had my 1978 Mainship 1 I put a 20 gallon plastic tank on the starboard side under the cockpit up against the bulkhead.
I could have done the port side as well, but I didn't want to re route the genny exhaust and the extra 20 gallons made us feel flush with water for the duration of our ownership.

 

[boomerang]

OK ,I'm going to do some more homework now, armed with this new knowledge I've gained. That's the reason I'm here; to learn and share anything I might have to share. Blissboat, I hadn't even given the CG any thought, though I had thought about moving the weight aft. The proposed placement in only 4" higher than where the tank currently resides, so I'm hoping it will have little impact. The boat is a little light in the aft anyway, IMO , and like Solly mentioned, his Mainship III-same hull- has the fuel tank with 200 gallons of fuel back there.
I just went down to the boat & measured. I have 11" of height before adding a shelf, so I'm starting to get limited. Especially if the fill is on the top, which is the only way I would be interested in a tank anyway, so as to have the maximum useable capacity.
Peggy & Parks, thanks. I'm still thinking that if I want to use the area I'm talking about, it'll more than likely need to be a bladder but I'll look for a higher quality one now.
Kimmel, no sir! You're not going to sit behind your computer in your warm house while I'm out there doing all of this footwork! You'll need to get your butt out in the cold & down here to help me get this darned project rolling!

 

[boomerang]

When I had my 1978 Mainship 1 I put a 20 gallon plastic tank on the starboard side under the cockpit up against the bulkhead.
I could have done the port side as well, but I didn't want to re route the genny exhaust and the extra 20 gallons made us feel flush with water for the duration of our ownership.

My starboard side is out of the question unless I remove the exhaust line. It's positioned so I cant get over or under it. Lots of wasted space outboard there ,too. Our muffler is in the right-hand side area where the generator used to be. The 4" hose exits in the center of the aft ER bulkhead and slowly ramps down to the outlet in the transom. I wonder how yours was different? I know it depends on the tank size ,but I did have a 9 gallon (Todd?) tank outboard of the stringer on the port side, which helped a little, but I took it out to use the space as fender stowage. I measured and don't think I found any off-the-shelf tanks bigger than 9 gal that would fit in that space.

 

[HeadMistress]

I cut my boating career teeth working for a Hatteras dealer in the very early 80's. They called it a salon so far be it from me to argue with Mr Slane or AMF or whoever owned them at the time!


That would have been about the time that "political correctness" had just begun to rear its ugly head.


I hadn't had an excuse to dust off my1983 Merriam Webster Unabridged in at least 10 years. I've considered getting rid of it several times...I'm glad I didn't!


--Peggie

 

[Comodave]

Given the limited vertical clearance you have it may be worth the extra effort to make the shelf down between the stringers instead of on top of the stringers. It would get you the thickness of the shelf material, whether you use 1/2” or 3/4” plywood. Then you would still have the clearance you currently have. It would be a bit more work but to get the extra size tank in it might be worth the work. I agree that Ronko tanks are the best choice if you can shoehorn it in. Good luck!

 

[Jeff F]

Can't speak to bladders, but on the sistership boat I had the PO had added a second rigid tank under the cockpit. It was smaller than the OEM, think he told me it was 30 gallons.

 

[Conrad]

Our previous boat came with a water bladder (plus a rigid one) which was dead on arrival. We replaced it and within a month it was leaking at the fitting. It turned out that the constant motion and filling/emptying put too much strain on the connection point and we were advised to go with a rigid tank which we did.

Peggie is absolutely correct; the saloon is normally where we quaff, not coif.

 

[Southern Boater]

(if you're looking, it's SALON, Mr RT Firefly, NOT SALOON! ),

He may not be looking but I am...and SALOON is actually the correct term...or was until the mid -1980s when the marine industry decided to market boats to anyone with a pulse and a credit card with high enough limit to make a down payment, few if any of whom had the slightest knowledge of nautical terminology. Till then, the 1st definition of "saloon" in most dictionaries was "any large room or hall designated for receptions, exhibitions, entertainments etc, specifically the main passenger cabin of a passenger ship." In fact it was the first half of that definition that led to drinking establishments being called "saloons."
As "salon" began to replace the correct "saloon" in boat marketing literature (God forbid the marine market would risk offending any buyers or try to educate them), it created quite an uproar among boat owners old enough and literate enough to know the correct term.

Sadly, knowledge of correct nautical terminology has now deteriorated to the point where the nautically illiterate are now correcting those who still use the correct terms.

(Tomorrow's lesson will be on the correct spelling and pronunciation of "gunwale.")

--Peggie

Thanks for clearing this up Peggy, I thought it was just a USA terminology thing.
Over here a salon is where hair is cut and styled.

 

[Solly]

How about a horizontal tank ? 10" or so high, as long (4') as you can get it to fit and what ever width between the transom and rudder. Run a piece of plywood across the stringers, support the outboard ends if you have to. Better yet use alum. angle to support the plywood and hold the tank in place.
That space is a bear to get to but you'd only do it once.

 

[O C Diver]

On a somewhat different track, I might be tempted to buy some 5 gallon water containers before investing in the tank. Filling them up with water and placing them where you would put the tank, would give you an idea of how it might effect the trim. It's also a pretty simple matter to poor them into the main tank after you've used most of that water.

Ted

 

[rslifkin]

On a somewhat different track, I might be tempted to buy some 5 gallon water containers before investing in the tank. Filling them up with water and placing them where you would put the tank, would give you an idea of how it might effect the trim. It's also a pretty simple matter to poor them into the main tank after you've used most of that water.

Ted

And you can use them to carry water to the boat when a hose isn't an option.

 

[PM]

I don't know an awfully lot about Mainships but my Albin, as well as MANY other trawlers tend to ride a little low in the bow. This bladder tank would help my boat but I already carry 350 gallons of fresh water so there is no room nor any need. But for you, I would say "Go for it"

pete

 

[boomerang]

On a somewhat different track, I might be tempted to buy some 5 gallon water containers before investing in the tank. Filling them up with water and placing them where you would put the tank, would give you an idea of how it might effect the trim. It's also a pretty simple matter to poor them into the main tank after you've used most of that water.

Ted

I have to slither into that area like a snake because there isn't any direct cockpit floor access so stowage of anything in that area is out of the question. That's why I'm thinking a once & done tank installation. I don't feel that the added/relocated weight is going to present a problem but that's just a gut feeling I have for the boat in general. While cruising, we add the extra weight a dingy & paddleboard on the platform plus a small Honda outboard and a large cooler in rear of the cockpit and I can't perceive too much difference in speed or handling.
Now watch...after saying that, I'll get a tank mounted and plumbed ,we'll cast off the lines and the boat will handle like we've entered a log rolling contest!

 

[jleonard]

You could cut your exhaust hose, install the tank, then make a connector using fiberglass tube. How old is the hose anyway? Maybe due for a replacement?

I only filled the extra tank by using s connector hose from the bottom of the main tank to the bottom of the extra tank using a T. I vented the extra tank into the bilge so there was no added holes to the hull.

 

[boomerang]

You could cut your exhaust hose, install the tank, then make a connector using fiberglass tube. How old is the hose anyway? Maybe due for a replacement?

I only filled the extra tank by using s connector hose from the bottom of the main tank to the bottom of the extra tank using a T. I vented the extra tank into the bilge so there was no added holes to the hull.

The exhaust system is relatively new and in excellent shape. I don't have too much of a problem with removing it but then it seems I would have some pain-in-the-butt wood/fiberglass work to do to build a shelf for the tank all the way outboard-only the far outboard stringer is available which means I would need to glass a shelf-support stringer all of the way outboard next to the chine. Plus I've finally juggled the heavy static stuff around (water heaters, AC units & batteries) so that the boat sits pretty level... unless I forget to swap fuel pickups & returns accordingly. I've just got it in my hard head that I want to use the large empty area under the cockpit and it just seems a good place for the H2O tank.
I do appreciate all of this input from everyone. Maybe I need someone to smack me upside the head and explain to me that I need to quit worrying about starting this project & concentrate on the other pending ones...like the freakin' heavy isolation transformer I have sitting in the floor of the kitchen that I'm too lazy to even tote down to the boat, much less install...
Actually, the transformer I bought is what started all of this. I want to mount it on the bulkhead under the cockpit & the damn water tank is in the way.

 

[boomerang]

Well, damn it, this has turned into a project! I can do a lot of things but building a cardboard box isn't one of them. Geez. 1 hour later and several hundred yards of duct tape all for me to drag my giant 50 gallon Ronco plastic tank mock-up down to the boat & find out there's no way it's going unless I drop the rudder & maybe remove a cockpit deck support. I'm coming to the conclusion that I'm going to have to go with a flex tank after all. Either that or we're going to have to rethink our personal hygiene habits and cut back on the showers. I'm pretty sure Liz isn't going to give me that option.

 

[rslifkin]

If the tank will fit but is too big to slide into place, could you put in 2 smaller tanks and tie them together?

 

[HopCar]

Talk to these folks.
http://www.atlinc.com/index.html

 

[OldDan1943]

If the tank will fit but is too big to slide into place, could you put in 2 smaller tanks and tie them together?