Wednesday, December 7, 2016

It's All in the Details

Yesterday, Erik and I spent the day together in the cockpit. The seas were calm, the sky was postcard-blue with little fluffy clouds, and we were glad. My seasickness behind me, we even shared a beer as the sun dipped below the horizon.

Pretty idyllic, right? Well. Let's add in some details.

Yesterday, Day 8 of our slowest passage in six years of sailing, Erik and I spent the day together in the cockpit cleaning a bad load of fuel. Finally the seas were calm, and the 40+ knot squalls that had plagued us for a week had given way to a sky of postcard-blue with little fluffy clouds. We were glad the cargo ships all around seemed to notice us, and no one had tried to run us down for at least 12 hours. Eight hours of diesel work shook my optimism that my seasickness was behind me. But, by the time we finished, nothing could stop us from sharing a beer as the sun dipped below the horizon.

"So, Amy," I hear you ask, gently skirting past my allusions to pathetic 50 NM days and knock-down winds, "how does one clean bad diesel? And how did that happen in the first place?" (Erik just asked me if I mentioned The Engine Impeller That Shredded Itself And Everything Overheated And We Lost 18 Hours, but I think I'm asking enough of you already.)

I'm glad you asked. Now, I'm not a chemist, so bear with me, here. As I understand it, we ended up with a load of so-called biodiesel in Bali. It looked like nice, clean fuel going in. However, the short-chain hydrocarbons in the biodiesel stripped the nasty tars and sludge from the walls of our fuel tank, and put those nasties into solution. Those dissolved or loose particles proceeded merrily to clog up our fuel filters, plugging them solid in mere hours. Not so good. In fact, an engine killer.

The short version of the story is that we could use our aft fuel tank without any issues (it was scrubbed not too long ago), but the middle tank was no good. That means about 350 L of fuel just sitting there, doing us no good whatsoever. Well. We could hardly let that stand.

So the first calm day that came along (day 8), we pumped a load of diesel into a five gallon pail. And then the testing began.

Method #1: Paper towels in a funnel
We poured a little diesel onto two paper towels stuffed into a funnel. If we had had coffee filters aboard, we would have tried those first. This method grabbed a lot of gunk, but was very slow. We also had concerns about tearing. Bottom line: unless we wanted to dribble-filter for the next six hundred hours, we needed a better method.

Method #2: Paper towels in a funnel lined with accordioned aluminum foil
For the increased surface area, of course. Still not fast enough.

Erik and I sat there, tapping our blue nitrile gloves against our knees, thinking back to our laboratory days and bouncing ideas around.

Method #3: Microfibre cloth in a funnel lined with accordioned aluminum foil
Bigger pores, but not big enough. Too slow.

"I've got an idea," said Erik.

Method #4: Microfibre cloth on an inclined plane
We used clothespins to attach a microfibre cloth to a foil baking tray. We placed the tray at a small incline, then poured diesel in at the top of the incline. It was much quicker, and the cloth, to be fair, did grab some sludge. But later diesel would often bump the sludge along into the collection pot, so X to that one.

"The funnel method was better," said Erik. "But what we need is pressure. Do we have anything we could use as a column?"
"I don't." Tall, cylindrical kitchen implements are too tippy for a boat.
Erik snapped his fingers. "Hose. I've got lots of that." He disappeared into the lazarette and came back with a meter length of sanitation hose. "Now what?"
Hmm, columns. Stuffing the tube full of cloth to mimic a real column was only going to block the flow. "How about we tie a filter around the end?"
"I like it." Quick as a flash, Erik had ziptied two j-cloths onto the end of the hose.

Method #5: Two layers of j-cloth individually ziptied to the end of a 1 m length of hose
This was the stuff. Erik pumped the diesel into the top of the column, and we got a lovely product out the other end.

But during our experiments, we noticed a water layer at the bottom of the product pail. We shook our heads. Not just sludge to worry about, but water, too. No wonder this tank wasn't giving us any joy.

And so, after a morning of trial and error, here was the final method we landed on, soup to nuts:
Method #5b: Decanting step followed by two layers of j-cloth individually ziptied to the end of a 1 m length of hose
1. Insert rigid 3/4" PVC pipe into fuel tank. Use flexible hose to connect the pipe to a custom fitting on the lid of a 5-gallon pail. Attach vaccuum cleaner hose to second custom fitting on the lid. Turn on the vacuum. (This is our patented "yuck bucket" method of cleaning bilges, etc - it sucks the product into the pail instead of into the vacuum. Nifty, no?)
2. Haul the full pail up to the cockpit, trying not to spill. Set on the bench.
3. Use the hand fuel siphon pump to gently suck off the top layer of fluid (diesel) into a clean 25 L jerry can (stage one jerry can), stopping before the water layer begins.
4. Recover the remaining diesel from the pail by hand decanting between two clear 600 mL pots. Pour the diesel into the jerry can, and dump the water into a waste bucket.
[By this point, the fuel was already looking better. A lot of sludge stayed in the water layer.]
5. Rest the filled stage one jerry can on the cockpit combing. Attach the hand fuel siphon pump to the top of the column (hose plus j-cloth bag). Hover the bag over a funnel placed in the mouth of the second stage jerry can on the floor. Begin pumping.
[The diesel pushed its way through the pores in the bag, leaving the gunk behind. And the pump/gravity made sure we kept up flow. Erik managed the top end, and I worked the lower level. If we'd had a hand free, we would have high-fived.]
6. Repeat until you have cleaned as much fuel as you can stand or you succumb to diesel fumes.

Just what you would have suggested in the beginning, right?

In the end, we cleaned 125 L of fuel. It's sitting in jerry cans tied to the rail, and in a perfect world we'll never need to use it. Is it better? Yes. Is it better enough? I'd rather not find out. Our winds have improved since we reached the South China Sea, so we've been sailing slowly instead of motoring slowly. When we get to our check-out port, we'll stock up on filters and new fuel, and hopefully will never have to try out the iffy stuff we cleaned ourselves.

And that, my friends, is romance on the high seas.


Kevin Baerg said...

What a great post! Love your creativity and teamwork! Excellent idea on the yuck bucket - wish I would thought about that before fouling my shop vac! Where did you find the fittings for the lid?

I'm sure curious if the fuel is clean enough to run!

Sail on!

Anonymous said...

This post deserves more than one comment. Nice work and thank you for sharing. Please keep it up. I enjoy your writing.

Dennison Berwick said...

Congratulations on your ingenuity and hard work - the essence of the cruising life, no?
I'm curious how well the biodiesel " cleaned" the gunk from the sides of the tank?
Season's greetings and all the best for new horizons in 2017