Cheoy lee 50ft Tricabin hull lines

Good morning all
I bought a 81 50ft Cheoy lee tri cabin last year. but have no way of calibrating the fuel tank as its double bottom except from hauling the boat and taking hull lines or emptying the tank and metering refilling at the same time. Both are laborious and time consuming and costly.

Does anyone have access to the hull lines? I have tried Cheoy Lee, who I might add have been very helpful with information, but will not release a set of offsets to me for royalty reasons which I appreciate.

Hoping someone out there has a set of offsets or hull lines I can take measurements from.

contact martin.purser@gmail.com

Martin J said:

or emptying the tank and metering refilling at the same time.

Click to expand...

What's wrong with doing the above if you really want to know the capacity of your fuel tanks?

Martin J said:

emptying the tank and metering refilling at the same time

Click to expand...

For what it's worth: I did this the first time I filled the tanks on Island Eagle. I marked them every 200 litres (roughly 50 gallons). It only took about an hour, and now I know it's accurate.

Jonathan at Cheoy Lee provided me with sounding measurements for a newer model of my 40 LRC. I have found those measurement (gallons per inch on my sounding stick) to be very accurate. If you haven't already do so, ask if they have fuel tank sounding measurements for the 50 tri cabin.

Good morning all

Thanks for the idea's

I did speak to johnathan Cannon at Cheoy lee and the details /info for my sounding stick has been lost. There goes the problem! No reference at all.

I was hoping that another member has one of the tricabin 50's 8 built and still has his sounding stick chart.

Failing that The only options are to drain remaining tank fuel maybe 400 galls and completely refill tank. The tank holds some 1600 galls @$5 per gall Caribbean prices. Some $6-7000. It would be very accurate When finished however

Another option would be to use my floscan consumption to watch movement on my sounding stick, problem is it would take forever.

The next option would be to drain tank and use metered water, expensive @$.35 per gall here in the caribbean, plus messy and would have to ensure water scrubbed out of tank.

The most practical is to use the hull lines and calculate the volumes in a spreadsheet for every inch of depth. A simple calc if I had the offsets.

And lastly, I do have the digital capability to take the lines, just the haulage costs etc. Obviously would like to do it as cheap as possible.

Martin

Martin J said:

Another option would be to use my floscan consumption to watch movement on my sounding stick, problem is it would take forever.

Obviously would like to do it as cheap as possible.

Click to expand...

I didn't realize you have FloScan aboard, Wouldn't that be the cheapest & most accurate method?

Hi Seahorse 11


Sadly the floscan would over time show usage and consumption, and by using the sounding stick. get a result by fuel used on the floscan versus the inches of movement on the sounding stick etc. In reality it would take many miles and many dipping's with lots of fill ups to get reasonable results.

The problem is it's irregular shaped tank, round bottomed and tapered and high capacity. 1600 galls. Once I know the inch's + gallonage in the tank I will install a cruzpro programmable gauge. Which can be programmed to fuel = inches and will calculate anything between. real nice equipment. So my bridge gauge will show gallon's remaining in the tank..

That's the plan, I think I will have to go with taking the offsets of the hull digitally when I go back to Sint Maarten in April.

Thanks for the input

Suppose for a moment that you have no digital measuring techniques available now or ever, how would you do this?.

For good readings from a site tube or dip stick, your tank doesn't need to be empty. Start adding fuel and every 50 gallons mark off and measure the level. You can estimate the lower unmeasured volume vs height from these early readings with some grade 5 math, no differential equations needed. The next time (or now when 25% full or so) you draw the tank way down measure the lower part too. Voila, job done. That is how I did it on mine. Even with a oddly sloped bottom I was very close on the estimates, to within 5 gallons.

When offshore cruising, no matter how good your sonic, magnetic or resistance type measuirng devices, backup check with your site tubes or dip stick.

Simply use the Floscan technique to continue to accurize the fuel used readings.

With a bit of diligence you can get to about 1% accuracy , comparing fuel used and what you take on a refill.

Not as simple as a stick , but most folks wont go below 5% or 10% remaining to keep the fuel cool.

With multiple tanks , a simple log when switching tanks works fine.