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2011-08-11

Tank battles



Meet Starboard McStainless, the 100 gallon water tank I hauled out yesterday. Nice piece of work, yes? Inspection port, threaded outlets and inlets, an internal baffle, very little in the way of scratches or rust. Why would I want to yank such a nifty tank out of the bilges of Alchemy, one might ask. And, with dimensions of 48 x 24 x 20 inches, and an engine room hatch of 48 x 24 inches, would I perform Moebius-strip contortions to get this beast out? (Not to mention the removal of the pilot house roof and the use of a truck crane?). It came out, in the end, fairly smoothly, although grabbing the thing in yesterday's high winds as I yelled instructions to the invisible crane guy via another guy on the side deck was quite stimulating.

But why? Well, here's the deal. The sibling to this tank, Porty McStainless, is identical, save for a top end hose barb that takes the deck fill hose, which snakes torturously through a tool locker to reach the break in the deck. The fill routine consisted of filling this port tank to overfilled status, at which point a hose would fill the starboard tank. When were they both filled? When the boat stopped listing and water came out the starboard vent.

The shortcomings of this method were many. Worse, however, from my point of view, is that these tanks are (or were) mounted on angle iron a good two feet off the hull. Filled tanks, or worse, ONE filled tank, actually made my steel boat a trifle tender, because the weight was too high. In somewhat heavy seas in 2007 (yes, Lake Ontario can throw up the occasional eight to 10 footers if it's been blowing 30 knots all day from the east or south-east), these tanks BOOMED as they flexed and sloshed as the boat pitched forward and back.

The baffles, they did nothing.

Lastly, those fine inspection ports were on the TOPS of the SS tanks...within one inch of the underside of the pilothouse deck. Unless one was willing to unbolt the tanks, take apart the hoses, remove the engine and yanks the tanks under the hatch, nothing was ever going to get inspected.

Well, that's not going to work, is it?

So I decided that I wanted to improve my boat's "stiffness" by getting the water tankage (which is the better part of one tonne and is "non trivial" in terms of ballasting the hull) lower, resting just off the hull in through-bolted angle iron supports (the bit I liked), and placed between the frames. For ease of handling and management and even for trim purposes, I'm opting for four approximately 50 gallon water tanks, made of HDPE, ideally. They will be small enough not to require baffles, and low enough to keep the weight where it should be, as close to the keel as is possible.

Something like the above, times four. Inspection ports are at knee height, all hose fittings are accessible, there is now air above for hanging awkward light stuff like fenders, pipe and lengths of hose (all secured, of course).

Why four tanks? Aside from the insurance that if one tank goes "bad", there's three others, we intend to get a smallish watermaker. The idea is that one tank will hold collected rainwater for "wash" water, water used to clean the boat, flush the head (a Y-connection allowing a freshwater flush or three of the head will get rid of many of the critters and sediments that would otherwise clog the works...apart from the usual traffic that can clog the works...), and do the onboard laundry.

The other three tanks would contain either trusted "municipal" water, or water we make ourselves while motoring in clean seawater. One of the reasons for having a double PTO on the new engine is to run twinned alternators to charge maximally the house bank when underway for the weekly holding tank pumpout, for instance. (Note to self. Make fresh water AWAY from pump out zone...ewwww....)

I will install two water fills (there is evidence one used to be on starboard, but is mysteriously under a welded plate), and will rationalize the tank vents so that even a capsize would be unlikely to put salt water in the tanks. I will also plumb these tanks so that I can pump water between them to keep the weight either high side on long reaches in trade winds, or to keep it in the forward two tanks for better balance.

Lastly, I will have foot pumps (I like the Whale type) plus pressure water in the galley. The galley will have the existing "domestic" tap set (pressure hot potable water from the hot water tank and the Flojet pump) and potable foot pumped water, and lastly, a hand-pumped seawater tap for "utility" wash ups.

It sounds complicated and expensive, certainly, but the decision to go with plenty of water tankage (it's the same amount in a different configuration, really), and a watermaker was not taken lightly, and is prompted by the same "shore-independent" set up that is driving the multiple charging sources design and the somewhat oversized battery bank capacity.

Everything's relative, of course. I understand 840-1000 Ah is not, in fact, as big as many folk with more amp-greedy gadgets than I plan to install already have.

Like this times three:

I just want to run my fridge and make the occasional SSB foray and netbook charging for five cloudy, windless days at anchor without thinking "damn, I have to fire up the diesel to make amps".

By the same token, 150 gallons of drinking water is considerable for three humans, even in the tropics. The ability to make it from the sea using amps made from the wind and the sun? Priceless.

Now, to get Porty out...

UPDATE August 22, 2011: The fine fellow who purchased the starboard tank phoned me to ask if I would trade it for the port tank (identical in size but the mirror image in plumbing fixtures).

So up it came. "Identical" in custom-made boat gear is a relative concept, as the tank proved about a quarter-inch wider than the hole in the pilothouse floor. Snug wasn't the half of it.

Anyway, using brute strength, 3D mental visualizations, and the Amazing Folding Wife, we managed to crane out the thing standing on its end, and away it will shortly go.

Now, to find a buyer for a starboard SS water tank!

8 comments:

Silverheels III said...

Hi Marc. Rainwater collected on our deck is our #1 source for drinking and washing up. It's free and generally plentiful after we've anchored; and the first deluge rinses off the salt from a passage.
Do everything that you can to collect off a clean deck and also the pilothouse roof. Most folks have a maze of clear plastic hose running rainwater hither and yon into various tanks. Making water using DC power and jerry-jugging ashore in the dinghy are the last resort. Water weighs more than diesel when you're carrying it. ;-)

Rhys said...

I wouldn't mind seeing how you collect it.

We will be in places with distinct dry seasons, and the "one tank rainwater, three tanks watermaker" is only a guide at this point. Mainly, the point of four tanks, two a side, is to sequester, measure and move our water supplies as needed. If we use a manifold and hand pumps to transfer it, we have the needed flexibility plus full access.

If the water's tasty and clean, I don't mind if it's three tanks of rain and one tank of watermaker.

At this stage, it's about the flexibility and the functional aspect of smaller tanks I can install and shift alone and that they go a lot lower in the hull. It was just silly having them more or less directly under the sidedecks.

Silverheels III said...

Lowering your ballasty things is good. Also stainless water tanks might impart a taste to the water. I know that aluminum does. We like HDPE tanks. I just cleaned out our port plastic tank. It was empty and after slurping out a few sponges full of residual water I removed a light tan coloured powder from the internal plastic surfaces....brown algae or Sahara dust..who knows?
We do not use chlorine regularly in water tanks. It's too hard on valves and hoses and is very difficult to rinse out of the system when water is not free on a dock. Water down here is either US municipal, island mountain lake fed municipal or RO; and RO water from friend's boats or side deck collected rainwater. We will install a 50 micron stainless mesh strainer on the deck rainwater filler to prevent larger particles from entering the tank. We have foot pumps only and boil a kettle for hot water. Pricy countertop domestid type silver nitrate ceramic filters in our view are designed only for fast flowing treated municipal water, not for boat use at all. Untreated water standing in a fine filter medium may support bacteria growth and cause more problems than they solve.
Peter from HMP gave us one great tip! Gardinia brand plastic garden hose manifolds are well made, non-metallic and are easily disassembled for maintenance/cleaning. They mate very well with 1/2" plastic water tubing in our bilge.

Rhys said...

Heh. Sahara dust is the seaman's fibre!

I have no plans to treat the water in any way apart from the occasional teaspoon of Clorox if I taste too many vegetables in my water. I plan on treating "caught" water like I do diesel, step one: As I have a Baja filter for the deck fill...BEFORE it gets to the Racor-equipped FilterBoss, so I would have a similar "first line of defense". I concur with the point of standing water. The key to clean water is to collect it and then drink it...don't let it sit for three months.

Peter's mentioned the garden hose approach and I am familiar with that manifold (I could buy two or three and get labelling!) and I have no objection, particularly as this stuff will never see sunlight buried in my hull. I can see a case for treating the hose end threads with pipe dope, perhaps, and to be fastidious with the clamping regime to reduce chafe as the wall thickness is considerably less than reinforced "plumbing hose", but otherwise I see no objections.

The goal is reliability, which does not always require an expensive, space-age approach. If flared copped works and doesn't invalidate the insurance, I have a flare tool and know how to solder stuff as well.

(That was just an example...I don't really intend to run copper pipe in a steel boat...)

Benners Adrift said...

Once again Meredith seems populated with cheapskate contrarians.

Our 150 gallon freshwater storage has never failed to meet our needs. Nowhere in civilized areas will you be more than 20 days away from fresh water. Even when we had to buy water the cost in both Green Turtle Cay Bahamas in February 2011 and in Bermuda in June of 2011 was 20 cents a gallon. You cannot buy and run a watermaker for that.

Like electrical power we find the key to water is conservation not production. We do not have foot pumps, which are a good idea, but we did plumb in a salt water pump to the galley for washing dishes and such. And we learned to take salt water baths and rinse with only a cup of fresh.

On Meredith we like chlorine in our tanks. Chlorine kills bad things. Remove it at the faucet. We use a purifier (not a filter) in the Caribbean where municipal water often does not have chlorine at all. The cartridges are hellish dear so we switch to a simple carbon filter to take out chlorine when in the US or now in Europe where the water is treated.

Watermakers also leave relatively large quantities of salt in the water and as the membrane ages this residual salt content rises. Even with close watch on the TDS meter you might want to monitor your blood pressure :).

All that said I am looking at a simple design for a home built watermaker that I might build for under $1,200 and at that price it would be a decent backup of the sort you hope never to need.

Benners Adrift said...

Nice looking battery installation.

Rhys said...

Yes, indeed. Since fabbing up various backing plates, steps, tabs and so on from aluminum stock, I quite enjoy working with it and would have no conceptual problem with the "tray, threaded rod, bar stock" solution, particularly as there will be little room to move around if I build the combo battery compartment/saloon steps properly.

I have learned a lot about effective crimping, too and now it's one of the first things I check out on other peoples' boats...the battery bay.

Rhys said...

Bob, in reply to your water tank comment, we are planning for a circ of five years' duration. We will not necessarily BE in civilization, nor are we always going to be near municipal-grade water...I'm thinking of some of the more distant atolls of Micronesia or in the Solomons/PNG.

We carry in our full-keeler 200 gallons of water (fifty of which is likely to be rain water) as much for internal ballast as for actual potable water, and we will have a watermaker of the smaller kind. Our focus will also be on conservation, with a similar foot pump and salt-water tap.

I thought long and hard about this not so much in terms of cost or even production, but in the level of complexity it adds and the amount of power it's likely to draw. Still, at this stage I'm remaining in favour of it, despite the complication, given that we want to be largely shore-independent and intend to go off the track entirely, never mind the beaten part...