Heaving-to in a Gale


#1

Not just a theory, I’ve done it. In 14 meters seas. How much the ship rolls depends on if the wave period and the rolling period are in sync or not.

Granted it’s an old book but this is from Merchant Marine Officer Handbook. Mariners should at least know this may be an option.

With plenty of sea-room, a vessel generally will lie easiest if the engines are stopped and the ship is allowed to take her own position relative to sea direction. This is markedly so where ship is not stiffly laden: i.e. if she has a relatively small GM.

EDIT: The problem on the El Faro was the list, so this would likely not apply to them.


#2

Haven’t tried it in a ship but one a boat have done it olenty of times and… you want to slowdown slowly rather than stopping altogether because sometimes you can find a better ride at a slower speed than you can stopped altogether.


#3

I’ve done it with a crewboat in a 4 to 5 meter sea. Easy peasy.


#4

Does anybody know what the wind forces were when you had to heave-to or is it an uncomfortable felling at the helm? Just wondering - Thx


#5

I prefer to heave to (with the sea more or less on the bow), or to run off (sea more or less astern).

Lying-a-hull works well when the sea is relatively large with a long period in relation to the size of the boat. But watch out for ocassional sets of larger seas with a shorter period.

Lying-a-hull can also result in heavy rolling that is really hard on the boat, the crew, and the lashings. I’ve had interior doors come off the hinges, stores and gear fly everywhere, lots of water leaking in around the deckhouse doors, crew slipping and falling, etc. Its that thorough audit that Kennebec Captain mentioned earlier.

Lying-a-hull can also result in making an astounding amount of leeway.

Running off makes much more leeway, it’s easy to lose 100 miles. Towing a barge it may take some throttle to keep ahead of the barge, and to keep the barge from lying-a-hull and rolling the cargo off. A big advantage of running off is that it’s usually the most comfortable ride with the least wear and tear, and the least amount icing up.


#6

This is a really interesting topic to me. Ever since I have read that section in Bowditch it has made me curious to a practical use.

I have never really experienced it in my short career. I have been in fairly heavy weather for the GOM (I estimated up to about 22 ft seas ) we just ran weather patterns going from quartering on the bow to having them on the stern. I have never really considered just letting it sort it out on its own due to a fear of finding a heading that would be beam to and just heavy rolling being the result.

Stability has always been a concern of mine. I am pretty observant of stability and know the basics but I feel there is always more that I need to know and no matter what, heavy rolling can cause concern on my end.


#7

That’s right, but it also may be important to estimate what will happen if you stop and drift. Sometimes it’s an option and sometimes it’s not.

You need to know your rolling period and the wave period, also you should alway watch to see how the boat behaves in a sea. For example in a turn when you expose the beam to the sea is the boat sluggish and doesn’t answer the sea or does it snap roll? Worse thing in seas near the beam is synchronous rolling, that might tear things up depending.

Also when you do stop with wind but no swell how does the boat lie? It will answer both the wind and the sea.


#8

I don’t know how old the info is in my Knight’s Modern Seamanship, here what it has to say:

9.22 Controlling a Ship in Very Heavy Weather The easiest position for a ship in a very heavy sea would be that which she would herself take if left at rest and free from the constraint of engines, helm and sails.

A ship left to herself in a seaway will usually fall off until she has the sea abaft the beam, the propeller acting as a drag and holding her stern-up. In this position she will roll deeply, but easily and will drift to leeward, leaving a comparatively smooth wake on the weather beam and quarter.
In such a state, she lies a-hull or is said to be hulling.


#9

Some real numbers from El Faro’s VDR data.

During the last hour of El Faro, without propulsion, with a lot of seawater inside and a heavy port list, the damaged ship found its equilibrium:

Bow heading = 325°
Course over ground = 230°

Advance speed = quasi 0 knots
Nearly perpendicular drifting speed = around 7 knots


#10

Wow. 7 knots is a lot of leeway.


#11

That sounds about right to me. I shut down and drift frequently on a PCTC with almost 5000 square meters of sail area. As a rule of thumb I figure 1 kt of leeway or drift speed for every 10 kts of wind speed. I have empirical data up to 70 kts wind speed, in 70 kts I was drifting between 6 and 7 kts sideways with a component ahead or astern.


#12

How a ship will find equilibrium by herself will very much depend on her configuration;
Superstructure Fwrd. / Midships / Aft?

Of course a PCTC, or fully loaded container ship with high deck cargo have a large windage area full length of the vessel and will be different again.

Small fishing boats frequently use a mizzen sail to keep them “2 point to the wind” when drifting:
2007_5d_mg_6153_450b_hsundbaat
BTW;That is also where most vessels/boats ride best when “hove too” in my experience.


#13

I have years of experience as captain in the Gulf of Alaska and the Bering Sea. I administrate a fleet of vessels about 240’ LOA and 2000 IGT. Some are house forward, some house aft. These vessels carry palletized cargo below decks, and a variety of cargo chained down on deck, everything from lumber to automobiles to containers.

Heaving-to in 40-foot seas is a commonplace activity on our freighters.In heavy weather we hove-to bow on to the seas, with just enough way to maintain steerage. If the rolling doesn’t exceed 25 degrees we call things good. If she rolls to 30, that’s to be expected. At 35 degrees, you curse. At 40 degrees, you wonder what you’re doing out there–just like you’ve wondered a thousand times before.

You might stay hove-to like that for days, making little or no headway, keeping just enough way ( 0. 5 kt. to 1 knot of SOG ) to maintain steerage. Lying-to in any other position causes severe rolls (35 to 45 degrees) and waves breaking over the side of the deck.

For years I have read authors advocating lying “a-hull”. For years I have seen what happens to the class of the vessel I have just mentioned, if they get anywhere near abeam to heavy seas. All I can say is that for the size/type of vessel I have noted here, lying a-hull is dangerous, as wold be instantly apparent to anyone who tried it.

I am not prepared to say what happens on ships of other sizes. I have sailed on 800’ container ships but do not have heavy weather experience on them.

I must also add that, for the size/class of vessel I have noted here, the safest point of steaming in heavy seas is with them on your stern. Again, I am being very specific here. I am talking about steaming in extra-tropical cyclones in the North Pacific. where the primary wave and swell set is coming from a single direction. Not the confused seas often found in a hurricane. In my experience, 50-foot seas coming from one direction are far safer than 30 foot seas coming from several directions.

My brother captains and I on the Aleutian Run have beaten our brains out for days heaving-to bow-on to heavy weather for more days than we would like to recount. We have learned that when the seas get to about 40-feet turning about and putting the seas on the stern, steaming as slow as possible to maintain steerage, provides the best ride. The difference between putting the seas on the stern as opposed to the bow is the difference between night and day. Rolling decreases. Pitching is less abrupt. The hull is not getting hammered. Waves no longer break over deck.

Riding even 45 degrees to the seas causes severe rolling and seas breaking over the ship, in excess of the the other two points of steaming. To be avoided at all costs.

Again, I’m being specific here. 160’ to 240’ LOA. 700 to 2500 IGT. 1500-to 3000’ HP. At least 6’ of freeboard, and enough cargo to keep the wheel in the water as the wave passes; without the latter you lose steerage. A host of caveats.

I have read authorities who state categorically that running before huge seas is dangerous, because of he danger of broaching. I can state that, in as far as they are being categorical, they are dead wrong.

One last word on the subject of heaving-to in heavy weather concerns deck inspections, Sometimes we have to heave-to bow-on to heavy weather because the wind is coming from the direction of our destination. We are waiting for the low to blow over us, until we can make headway again. This may take a couple of days. When seas are 30-feet or less, experienced captains will often turn the vessel about at mid-day and put the weather on the stern for an hour, to give the mate and crew an opportunity to check the deck for dangers, and check cargo lashings. Chief among the dangers are cargo hatch bolts and hatch dogs which have backed off after days of hull flexing, allowing flooding in the holds.

This practice of putting people on deck may seem dangerous, but as I have said, on this class of vessel, running with the weather on the stern, the experience of 30 years and 1800 voyages without a man overboard says it is safe, if the officers and crew are experienced, and precautions are taken. We’re not talking about a situation where waves are breaking over deck, which is the whole point of turning about.

In heavy weather, even on runs where heavy weather is common, like the Aleutian run, flooding must be assumed to be happening until you have actively determined it is not. This pertains to tank vents and chain lockers. Get water in your fuel and you are in a world of hurt. Witness the Aiviq/Kulluk fiasco.


#14

That’s interesting. It’s a tuning thing.

If you’re in a long swell the vessel will roll more then one time per wave. If the swell/wave got shorter and shorter a point would be hit where synchronous rolling would get more and more common. If the wave period was shorter then the roll period, which is what I experienced, with a low GM, the ship didn’t have time to complete the roll.

With the seas on the stbd side, at the trough it would still be rolling to stbd till part way up the next crest. Then half way up, it would start to roll to port, when the wave crest passed under the ship, the ship continued to roll to port, even while the back face of the (very steep) wave was on the port beam.

Just enough out of sync.


#15

Like the Gulf of Mexico those are small bodies of water which equals less fetch and this a shorter wave period than the open ocean

The same thing goes with supply boats in the GOM, they don’t lay a-hull well in seas.

I think those authorities are correct, it is more dangerous to run with the seas (but also more comfortable). Your evidence only shows that it’s a more comfortable ride, not safer.


#16

It depends on size.

The rule of thumb for pitchpoling is that the wave height must equal the length of the boat in order to pitchpole.

Broaching is a real concern in relatively small, especially shallow draft, vessels compared to the size of the seas. I don’t have a rule of thumb for that.

I’ve seen a 130 foot tugboat with a 15 foot draft run off light boat at nearly full power in really big seas with no sign of broaching and a good ride. I’ve seen the same boat headed up and dragged backwards by the barge for three days, a really miserable ride.


#17

One of my favorite ways to heave-to is to put the DP system in auto heading and drift backwards with the bow into the seas.


#18

Mariners do use simple rules of thumb. The simplest rule is to head into them, the need to slow down is obvious just from the boarding seas and/or pounding.

If there are two options then it head up or on the stern. On the stern requires keeping speed low but it’s not as obvious. Probably the reason it’s not done more often is because people associate it with a broaching type roll.

Laying beam to requires avoiding synchronous rolling. I can’t think of any reason that wouldn’t hold up with smaller vessels in Alaska or the GOM.


#19

Most of the times I find myself hove-to is running weather patterns on location, in which case I need to stay near a certain location. I prefer to head up and steam as slow as possible and still maintain steerage to avoid having to turn more often than absolutely necessary.

I’m just saying that smaller vessels roll much worse in those seas than larger vessels.


#20

In the photo here you see a red dot in the Gulf of Alaska, representing a ship crossing the Gulf of Alaska. Please estimate for me the fetch for any waves coming from west to south to southeast.

If you were to trying to determine if a certain practice was safe or unsafe, the accepted method is to run a controlled trial for a long period of time, approximating realistic conditions, carefully observing how many accidents occurred under controlled conditions. You would then extrapolate the results over a longer period, and arrive at your conclusion. This is accepted scientific practice…

We have essentially run that test over 30 years and 1700 voyages, under the most realistic of realistic conditions: Reality. The results: perfect safety. Hence, what would be the statistical conclusion?

Note: I was very careful in how I phrased my original assertion: “I have read authorities who state categorically that running before huge seas is dangerous, because of the danger of broaching. I can state that, in as far as they are being categorical, they are dead wrong.”