Saturday, October 10, 2009

Water, Water Everywhere...


My parents celebrated their 60th Wedding Anniversary this summer. I think that's quite an accomplishment. After all those years they are still completely devoted to each other and are the perfect example of opposites attract, my father being the ever logical engineer while my mother is led by her emotions.

Jeff and I just celebrated 24 years of marriage and would be better described as two peas in a pod. We both have math and science degrees and approach most every decision with logic and calculations. Remember our lists!

So in our calculations for getting to Cuba we decided it would be a good idea to see how self-sufficient we could be. Could we get to Cuba and back without needing anything other than what we brought with us?

Calculations for much of this are easy. Jeff's fanatical logging of our fuel consumption allows us to accurately estimate our fuel usage (see our article). I've done enough provisioning I'm confident I can feed us for 2-3 months. However, when it comes to water usage we had few firm facts. And as it turned out the facts we thought we had were questionable.

We left Maine with the notion that we would put ourselves to the test. In particular, we wanted to see how long we could last with our onboard water supply. This was more than just an interesting exercise. We have been having the great water-maker debate for some time. Do we spend $4,000-$5,000 plus installation on a water-maker which would give us a virtually unlimited water supply but also another system to maintain, or plan on buying water in the Bahamas and using that for our planned month in Cuba.

We gathered our facts and began our experiment. Our water capacity is listed as 450 gallons. We filled just prior to leaving Castine. We went into water conservation mode – saltwater wash-down on deck, military showers, no running water while washing dishes, etc. It was actually pretty painless.

When we purchased the boat the previous owner had thoughtfully marked the water tank site-glass in 1/4 increments. We figured we'd simply check our consumption weekly and log our results. At the end of the first week our tanks were less than 1/4 down – not bad. At the end of two weeks we were down between a quarter and a half – nice to know we're consistent. Then we committed the ultimate experimentation sin. As we knew we would be at a marina in Crisfield the next day, we did 3 loads of laundry and.... didn't checked the tanks before filling up at the marina. Why should we? We'd used less than 200 gallons of our 450 and laundry only took 15 gallons per load.

Upon leaving Crisfield we continued our experiment which turned out identical over the next two weeks. We were feeling pretty confident in our calculations and thinking maybe a water-maker could be avoided for now.

I then decided to do two loads of laundry before we left Solomons and the next day we headed off to our current anchorage in Horseshoe Bend off St. Mary's College. We were now at two weeks 4 days since we had last filled the tanks and I was thinking maybe I'd do one more load of laundry. I decided to take a quick look at the water level – it was off the scale! How could that be?


We put our two analytical heads together and decided the problem had to be the site-glass measurements. They were marked as linear measurements but in reality must be a curve. We poured in our two 6 gallon jerry cans we always keep in the lazarette and headed to shore to fill them 4 more times, giving us an additional 60 gallons of water. I looked at the site-glass and sure enough it showed we were between a quarter and a half full – or approximately 178 gallons of water based on a linear scale. We then took measurements of our water tanks and calculated they would hold around 300 gallons and not the 450 they claim!

So now we're back to square one. In two days we leave to go to another marina were we can fill our tanks. We are developing some strategies for determining the actual capacity of our tanks and a method for accurately marking our site-glass. I'm pretty sure it will involve me spending too much time in the bilge watching the site-glass. We will then begin our experiment again, hopefully this time armed with some real facts.

Please don't breathe a word of this to our college professors or they may want our degrees back.

6 comments:

Gino said...

Yiks, to much LAUNDRY

jeffnick said...

Our sailboat had a 20 gallon tank. We used a garden sprayer for showers (heating 1/2 gallon if/when necessary). We could go about 2 weeks by provisioning with nothing that required reconstituting and using all the fluid in the canned goods. We had a raincatcher that drained directly into the water tank; we learned early that the first minutes of a rain can contain many bugs.

Anonymous said...

For what it's worth, we have calculated that my wife and I use 10 to 15 gallons per day under normal circumstances - no extreme conservation measures, but no laundry. We always do laundry ashore.

Capt Wayne B
GB49, Long Legged Lady

TakingPaws said...

Well the calculations are in. We measured the tanks in 6 gallon increments to get a pretty precise measurement. We have 300 gallons just like our volumetric calculations determined.

Why would the specs of the boat say 400 or even 450 in some documents?

Capt Wayne B - we too find that 10-15 gallons per day is a good estimate. We lean more toward 15 with 2 dogs - they use more water than we do at times. So we can go about 3 weeks without water - OK for the Bahamas but questionable for Cuba.

Anonymous said...

Defender Industries has a watermaker that will produce 36 gals/day for about $3K:

http://tinyurl.com/ygt5rxq

Capt Wayne B

Ron said...

There is another philosophy and that is to get a watermaker with large capacity so that you reduce generator runtime. I think that in the plumbing section of Lowes you can find a Rainbird hose accessory that reads gallons so that you can measure how much you add to the tank. I'll look today when I go to buy George some ramp carpeting.