Potable Water and Epoxy

[Inquisitor]

Working through some threads about water tanks. Instead of using a bladder… I’d like to just cordon off an area that is already structurally sound (say a bay under a berth). If I lined it with fiberglass and epoxy is there an issue of being potable? I know homebuilt airplanes and boats routinely use unlined epoxy-fiberglass fuel tanks, so I thought epoxy was totally inert after it cures. Some thread on our forum indicated that the water needed to be run through carbon filters to remove organics. I planned on filtering anyway, but I didn’t want to add to a filter’s burden because of the tank’s materials.

[kmclemore]

I would not do that. Fiberglass is not non-porous, and as such will soon begin to get fouled with trapped bacteria, etc. My advice is to spend the money and get a safe & replaceable water bladder.

[Boblee]

I made the front tanks under the v berth out of Aluminium, tried to find out if this was a problem and then gave up and painted them internally but they are only used on long trips and then used first before starting on the bladder.
We also have a double filter with a 2 micron pre filter and a .5 micron carbon so hope we will live as for loading the filters, they last at least a year and even then they look and work perfect but have used the same filters in a camper where the tanks were filled with muddy water over five months and they were still giving perfectly clean water out although the prefilter was 3/4 full of mud.
This is similar but the micron ratings are reversed on ours as this one would be very slow IMHO.
http://cgi.ebay.com.au/Twin-Dual-Unders ... 20b02b120c

[DaveB]

I use a 13 gal. bladder on my Mac.X , I hand felt the rough glass of the hull and sanded any glass that prutruded and than laid a 1/8 inch hard rubber as a liner to protect it from Chafe.
This gives max. amount storage at a very low bilge point and helps keep the boat stable.
I have had no problems in 2 years and should last 10 years or more.
On a Mac. keep the center of gravity close to center line and as low as possible.
Dave

Working through some threads about water tanks. Instead of using a bladder… I’d like to just cordon off an area that is already structurally sound (say a bay under a berth). If I lined it with fiberglass and epoxy is there an issue of being potable? I know homebuilt airplanes and boats routinely use unlined epoxy-fiberglass fuel tanks, so I thought epoxy was totally inert after it cures. Some thread on our forum indicated that the water needed to be run through carbon filters to remove organics. I planned on filtering anyway, but I didn’t want to add to a filter’s burden because of the tank’s materials.

[restless]

How does one go about cleaning these orrid bladders?? And what do you do with them out of season? The standard ones seem to get mouldy by the end of the season.. I would not want to replace a plastimo 100l bladder every year!
Looks like I'll just have to make a ss one with a nice big cleaning access plate.

[kmclemore]

People use bladders all the time without issue. Always pop in the proper water treatment tablets and add an in-line filter and you're just fine.

[Russ]

If someone can come up with a water bladder tank that would fit inside the ballast tank, it would be quite the mod.
As you used water from the bladder, the water around it could be replaced by sea water.

Yea, I know, just a dream.


--Russ

[DaveB]

Just unhook the fill and the feed line after pumping most of the water out and take it out of the boat, clean and store it.
Dave

How does one go about cleaning these orrid bladders?? And what do you do with them out of season? The standard ones seem to get mouldy by the end of the season.. I would not want to replace a plastimo 100l bladder every year!
Looks like I'll just have to make a ss one with a nice big cleaning access plate.

[kmclemore]

If someone can come up with a water bladder tank that would fit inside the ballast tank, it would be quite the mod.
As you used water from the bladder, the water around it could be replaced by sea water.

Well, Russ, there's one flaw in that... you *do not* want your ballast moving around. That's why you only run with a completely full or a completely empty ballast tank... the sloshing of a half-full tank will make the boat seriously unstable!

[Kelly Hanson East]

Fit your water tankage to your intended use. Putting in a 50 gallon tank sounds great, but if you only cruise on weekends, you will spend a lot of time pumping out old water and keeping it clean. Ive found my small tank (in mods), refilling once on a week long cruise, is cheap and easy to maintain both on and off season.

[Inquisitor]

If someone can come up with a water bladder tank that would fit inside the ballast tank, it would be quite the mod.
As you used water from the bladder, the water around it could be replaced by sea water.

Yea, I know, just a dream.


--Russ

Are you yanking my chain?

http://www.macgregorsailors.com/forum/v ... =8&t=10524

[Inquisitor]

Well, Russ, there's one flaw in that... you *do not* want your ballast moving around. That's why you only run with a completely full or a completely empty ballast tank... the sloshing of a half-full tank will make the boat seriously unstable!

Technically, you're absolutely right. But in the real world am I going to take a five gallon shower while I'm in the middle of a taching duel? You take a 5, 10, 20+ gallon shower (depending on company) on the hook and keep the ballast tank valve open.

[Inquisitor]

Fit your water tankage to your intended use. Putting in a 50 gallon tank sounds great, but if you only cruise on weekends, you will spend a lot of time pumping out old water and keeping it clean. Ive found my small tank (in mods), refilling once on a week long cruise, is cheap and easy to maintain both on and off season.

Actually! This is the best argument against... I've heard. Thanks. Although, I dream of doing a Chinook long trip, I do spend 99% of the time weekending and daydreaming. Sincerely thanks... I was close to getting out the ole chain saw.

[Russ]

Well, Russ, there's one flaw in that... you *do not* want your ballast moving around. That's why you only run with a completely full or a completely empty ballast tank... the sloshing of a half-full tank will make the boat seriously unstable!

Technically, you're absolutely right. But in the real world am I going to take a five gallon shower while I'm in the middle of a taching duel? You take a 5, 10, 20+ gallon shower (depending on company) on the hook and keep the ballast tank valve open.

That's what I was thinking.
Now I'm no hydraulic engineer but let's say you could install 2 freshwater bladders inside the ballast tanks. You fill them with fresh water then flood the ballast tanks with sea water to achieve full ballast and no air in the ballast tank. Close off the air vent and open a raw water (well below the water line) seacock to the ballast tank. As you pulled fresh water out of the bladders, raw sea water would be drawn in and displace the fresh water you removed. Healing wouldn't drain the ballast unless some air could get in to allow raw water to escape.

Now the trick is the bladders would need to be installed during boat construction and kept really clean inside. If they got crud in them you are in trouble. Also, I don't know of any bladders shaped the way the ballast tank is shaped. You would have to insert sausage-like bladders into the "tubes" that run along the sides of the bottom of the hull. There is some more water in the bow section as well that might fit a square bladder.





--Russ

[kmclemore]

Yes, but my point was that when you run WITHOUT ballast, as many of us do when motoring, the bladders can shift and cause you to flip.

Your system only works if you *never* empty your ballast.

Never.