Sloshing Fuel Equals Near-Disaster

[ADMPRTR]

This is not my confession (although I am sure I could find a few ) but I thought I would share this story of a colleague at my marina who almost lost her boat.

She and her partner and their dog were heading into a rocky channel that is known for bad conditions when the wind pumps up.

On this particular day they were experiencing 20KT+ winds and up to 12ft waves crests. As the story goes, just as they entered the channel the engine died. They had sails up but were in irons and could not manoeuvre and had no time to drop an anchor. Within 20 seconds they were on the rocks being driven up onto the shore. The boat was lying on its side.

They put out two MAYDAY calls but only the first was heard by the coast guard because mast too low off the ground to transmit the full distance. Luckily, other boats at our marina were in the area and rushed to assist. Through a combination of good work and luck they were able to kedge the boat off the rocks by using the same waves that caused it to flounder in the first place. Apparently the boat was so far over that the keel could have been used as a dinghy ramp. The boat was floating by the time the coast guard arrived 28 minutes later.

The damage to the boat was extensive with rudder and skeg ripped off and perhaps other damage. But luckily, their boat is an old solidly built production sail boat and was not holed or taking on any significant water.

It was concluded that what caused the engine to die was a half empty gasoline tank sloshing around. Air was let into the line and the engine failed.

We are all grateful that no one was harmed and the boat can likely be revived but the experience stands as testimonial to keeping you fuel tank topped up and also to the fraternity of sailors who do not hesitate to assist, even at there own peril (one rescuer damaged his dinghy prop on the rocks).

[S/V Alchemy]

When I switched from a 15 gallon Monel tank to a 10 gallon Tempo plastic tank as part of an upgrade of the fuel system for my Atomic 4, I considered this as being a potential problem, and my boat partner and I make a point of constantly topping up. I doubt there is at any point less than 80% gas in that tank, although it's conceivable that a long motor would draw it down...but long motors don't usually feature 12 foot waves...you just sail.

So if I'm getting air in the line with it more than 80% full, I'm also probably getting water down the vent as the boat's on its side and I have bigger problems!

Glad to hear they didn't lose the Good Old Boat. I hope insurance will pay to rebuild their steering, because letting your tank go to 1/2 isn't really an "operator fault" in my view...they did all they could in a bad and rapidly moving situation.

Thanks for the tale.

[anjou]

Might it be the case that a better designed tank is needed? One with baffles and a sump to hold a reserve in extreem cases

[psneeld]

power vessels don't have that problem to that extent...more likely to suck up tank garbage than suck air.

better tank design/install is the answer...

[S/V Alchemy]

Possibly, but in the case of gasoline-powered inboards (still a large portion of the North American "fleet"), the gas tanks are usually smallish and are simply "boxes" of metal or plastic, because it's hard unless you motorsail or cruise in calm air to burn even 10 gallons of gas in a season. For me, for instance, in a 33 footer with an A4, that's about 13 hours of runtime at five knots...I typically run the engine for perhaps 15-20 minutes for every pleasure sail...just enough to get out of the basin and head to wind for sail raising.

So there's no incentive to carry a lot of "internal" gasoline (and some disincentive due to weight and fire hazard), and smallish tanks aren't generally considered worthy of baffling, although I agree that in this case it might have avoided the motor shut-down.

I've seen daytanks of 10 gallons or so specifically made with baffles and sumps to supply post-filter diesel, but that's to complement the presence of much larger keel or saddle diesel tanks elsewhere, which are usually themselves baffled.

[psneeld]

Originally Posted by S/V Alchemy

Possibly, but in the case of gasoline-powered inboards (still a large portion of the North American "fleet"), the gas tanks are usually smallish and are simply "boxes" of metal or plastic, because it's hard unless you motorsail or cruise in calm air to burn even 10 gallons of gas in a season. For me, for instance, in a 33 footer with an A4, that's about 13 hours of runtime at five knots...I typically run the engine for perhaps 15-20 minutes for every pleasure sail...just enough to get out of the basin and head to wind for sail raising.

So there's no incentive to carry a lot of "internal" gasoline (and some disincentive due to weight and fire hazard), and smallish tanks aren't generally considered worthy of baffling, although I agree that in this case it might have avoided the motor shut-down.

I've seen daytanks of 10 gallons or so specifically made with baffles and sumps to supply post-filter diesel, but that's to complement the presence of much larger keel or saddle diesel tanks elsewhere, which are usually themselves baffled.

My point being then the install or "position" of the tank is bad...small powerboats get airborne on a variety of occasions and don't "flame out" to any regularity...

As far as fuel burn...that's why so many saiil boat engines/gensets die a premature death....need to run them hard for an hour every week or so....

[ADMPRTR]

Originally Posted by S/V Alchemy

Glad to hear they didn't lose the Good Old Boat. I hope insurance will pay to rebuild their steering, because letting your tank go to 1/2 isn't really an "operator fault" in my view...they did all they could in a bad and rapidly moving situation.

I believe they will be covered. We were joking that our insurance company (we are both on the same plan) insures both stupidity and valid accidents. This situation is clearly the latter so they should be okay.

[Snore]

As a newbie with large boats, I would like to ask a rookie question. Would a well designed 2-3 gallon day tank avoid allowing the intake to suck air?

Bill

[S/V Alchemy]

Originally Posted by psneeld

My point being then the install or "position" of the tank is bad...small powerboats get airborne on a variety of occasions and don't "flame out" to any regularity...

As far as fuel burn...that's why so many saiil boat engines/gensets die a premature death....need to run them hard for an hour every week or so....

You have a good point that is hard to resolve on most smaller sailboats, where the fuel tank is frequently offset to either the bottom of the port or the bottom of the starboard cockpit locker. You're not supposed to run your engine above certain angles of heel, but still, you can see where fuel tank positioning could go wrong.

As for premature death, I agree...if it's an auxiliary diesel. But running a low-compression Atomic 4 infrequently is not a problem. It's no worse than running a chainsaw once a week...and the Atomic 4 is not greatly more complex than a chainsaw engine.

Running a diesel for 10 minutes and then off, particularly with cold raw water, can be a real life-shortener.

[S/V Alchemy]

Originally Posted by Snore

As a newbie with large boats, I would like to ask a rookie question. Would a well designed 2-3 gallon day tank avoid allowing the intake to suck air?

Bill

Generally, yes, because by definition, the daytank would be kept full via some sort of dedicated fuel pump arrangement. Its contents can then be sent to the engine by gravity, lift pump, electric pump or, as in the case of an Atomic 4, a mechanical diagram pump of low pressure (I think it's 2 PSI).

A full tank can't let air in, because the pickup tube or hose from a sump is never exposed to air even if the boat's in an unlikely attitude for motor operation.

[thinwater]

I have had an engine fail in a rock lined channel--three times--and twice I was saved from misadventure by getting an anchor down FAST (the third time the wind was fair in direction). Since we have the anchor secure only by the windlass and a quick release pin, we probably had the hook on the bottom in 10-15 seconds from deciding it was the thing to do.

The lesson I learned--one was an overheat and the other was water in the fuel--is to run the engine long enough before entering the harbor to be certain it is running well. At least 50 minutes. It's surprising how many sailors make a point of not using the engine, and then wonder why it lets them down. Yes, they need to be run hard enough hours each season, or they will die prematurely. Bragging that the fuel is dirty an stale because you use so little is a little silly.

[rgscpat]

Of course, there have probably been many threads on gunk in diesel tanks, which is a whole another, but slightly related critter to this thread.

[Tellie]

12 foot wave crests in a rocky channel?
Not judging, just sayin.

[S/V Alchemy]

If the channel's facing NW and we are talking Lake Huron or Georgian Bay, that's entirely possible if it's been blowing from that direction at 25-30 knots. Georgian Bay in particularly shelves to shallows very rapidly.

That's still not as bad as the river bars in the PNW, though...

[ADMPRTR]

Originally Posted by Tellie

12 foot wave crests in a rocky channel?
Not judging, just sayin.

It is easy to judge:

• If you go and survive, you are praised for your skill, seamanship and cojones.
• If you go and fail your seamanship is called into question.

Originally Posted by S/V Alchemy

If the channel's facing NW and we are talking Lake Huron or Georgian Bay, that's entirely possible if it's been blowing from that direction at 25-30 knots. Georgian Bay in particularly shelves to shallows very rapidly.

The channel in question has a north-south orientation and is in a bay that narrows and channels the waves. As I recall, on this day it was a WNW wind which would have been roughly perpendicular to the boat and channel direction. It is also possible that the size of the waves was inaccurate (I was told about it by a third party) but I am sure they were sizable (you know how sailors will make waves 50%-100% bigger than they actually are...).

My guess is that the portion of the channel that was exposed to these conditions was fairly short but apparently not short enough. They may have felt that it was a acceptable risk, or underestimated the build-up in height.

We all can find ourselves in situations where we are on the wrong side of a rough channel and are faced with 30 seconds of terror to enter or hours of rough sailing to detour to another entrance. It is a balancing act, do you enter a potentially dangerous channel that you know or do you plot and run to an alternative that would be a better choice but further exposes you to the rough weather?

Assuming no mechanical failure I would think many skippers would go with the former. I know my self that I have made that decision (it still gives me the willies years after and it wasn't half as bad as this).

Some sailors don't go out if the wind picks up more the 15kt. This couple do not fall into that category and I see their only fault was having a small gas tank that was not full.