Heaving-to in a Gale


#41

No that was not me. Probaby somebody needing some fresh air, away from the stench inside…:smirk:

Those supply vessel captains sailed through anything preferably at full throttle. Slacking down was not in their vocabulary.


#42

That’s what I’m saying. I’m not trying to “sell” the world on the idea of heaving-to with the skinny part the wrong way. Just saying it sometimes can be done, contrary to what seems to be conventional wisdom.

Not theory, I’ve done it in 14+ meter seas.

The APL China is an example where taking the seas on the beam at 15 degree rolls vs the 40 degree rolls head-to with huge insurance claims.

The peril of the sea that modern merchant mariners are most likely to face, navigational wisdom holds, isn’t a monsterwelle but something known as “synchronous rolling,” so called because the natural roll period of the ship falls in sync with that of the waves

The ship’s captain did exactly what all captains are trained to do: He hove to, immediately turning into the oncoming waves and slowing down, letting the ship ride up and over. “All the books say that you’ve got only two minutes to break that cycle. You’ve got to make a hard turn and get the bow up on a wave or down into a trough. Another 30 seconds and I think we would have rolled right over.”

Then he told me the story of what he believed to be the most famous case of synchronous rolling: the case of the APL China.

Officers reported rolls as steep as 40 degrees steeper and more violent than the steel lashings had been designed to endure.

If such a ship in such conditions had lost power, it would have drifted into beam seas and, because the waves were out of sync with it, rolled no more than 15 degrees not enough to snap the lashings.


#43

Running before the weather (i.e. stern into wind and waves) is a fairly common practise among Norwegian fishermen, or al least used to be before the large new and powerful fishing vessels took over.


#44

I have done this plenty of times in sailboats. The easiest way to describe it is you tack, do not release the jib, and once the sail fills backwinded you turn the helm hard to windward and lock it down. The rudder, main, and jib forces reach an equalibrium and the boat will sit about 30-45 degrees off the wind holding steady and moving very slowly forward. This is a great way to let the crew get some rest, perform repairs, make dinner, or maybe just hang around waiting for dawn to enter port.
This used to be taught as a survival mechanism back in the day, but not so much anymore. Not all modern boats can do this well. Translated into powerboats and ships, I always thought this translated into holding bow nearly or straight into the wind with just enough power to steer. I have done this when delivering a large power cat. It required someone on the helm and occasional differential power, but it worked and we pretty much stayed put until the storm passed with no damage.
Lying ahull for small craft is pretty much a desperation move now. I think back in the day with very narrow boats that had positive stability all the way to 179 degrees or so it worked better. Now…not so much.


#45

I spent some years in the North Sea in the 70s and 80s and once had the opportunity, while standing by a semi North of the Shetlands with clear decks, of testing the ship’s natural tendencies in rough weather with the engines stopped. It lay with the wind on the quarter and was comfortable in a Force 9. The ship was a UT734, one of two which worked as Shell’s anchor-handlers out of Aberdeen. I attach a picture of the sister ship Star Spica, taken from my ship, towing a semi-submersible on a choppy day back then.


#46

Manoeuvring the vessels in Heavy weather at sea

When the period of the ship is large in comparison with the period of encounter she will roll or pitch independently of the waves In a beam sea this should mean a comparative easy motion, though waves slapping against the weather side may make her wet. (Red Ship)

When the period of the ship is small in comparison with the period of encounter she will tend to ride the waves, keeping her deck parallel to their slope In a beam sea this will result in rapid, heavy rolling (Yellow ship)

image


#47

You left out the part where they are equal :scream:


#48

Do you have access to a downloadable PDF of that?


#49

I don’t have experience with this on ships but I do on sailboats. Best option is to heave to on sailboat as yacht_sailor said but with minimal canvas up. Here’s a picture:

image

Your next best bet is a drogue off the stern or a sea anchor set off the bow but with a running line to put it at an angle.

image

The key is to have some assistance to reduce the motions but a very minimal amount. Sailors get in trouble quick when they throw huge sea anchors directly off the bow or stern.


#50

Drogues are an interesting subject for discussion. They were mentioned earlier in the topic “Following seas and follow up steering”
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#51

The subject of beams seas has as well: Vessel with seas Beam-on


#52

When I was on that run we never used the direct Dutch to the “J” Buoy in the winter. We always used the inside route.


#53

We steam directly from Cape Flattery/Buoy Juliet to the Alaskan Peninsula far more often these days than we did even ten years ago. Ten years ago perhaps 5% of all voyages went “Outside”. Now about 20% of our voyages go Outside.

The reasons;

  1. Bon Voyage weather software. In the old days we used the Inside Passage nearly all the time, because accurate weather routing using weather faxes and radio reports in the volatile Gulf was error prone, and the penalty for making the wrong decision was a shellacking out in the Gulf. It was just easier to stay on the Inside Passage.
    But with Bon Voyage you can often route the vessel around the worst of the weather with accuracy. As our captains say, “It’s amazing how many fewer storms we’ve had since we started using Bon Voyage.”:grinning:

  2. The cost of grounding is more expensive nowadays. In the 1980’s a boat could T-bone BC’s solid granite shore and the owner walk away with just $100K in repairs. Nowadays you’re probably looking at five/six times that, not including a rise in premiums.

3)The government of BC has become far less forgiving of groundings, beginning with the Nathan Stewart grounding in fall 2016. The process to get a BC pilotage waiver has become more rigorous.

While we have an excellent record, and have started a training program exclusively for our new deck officers to meet the waiver requirements, the surest way to avoid running aground on the Inside Passage is not to use it. Using the IP less statistically decreases the chance of grounding

There is always a decision to be made when running between Seattle and the Aleutian Islands:

  • Use the IP to avoid danger to life-and-limb/cargo damage in severe weather, with a increased chance of grounding or–
  • Head Outside, with no chance of grounding but get shellacked by severe weather.

As you know there are three major routes on the Inside Passage, as well as going Outside. The company’s policy is for captains to use the widest body of water that allows the vessel to make headway for the given weather conditions. Therefore, if the Bon Voyage forecast and captain’s forecast agree that there would be good weather in the Gulf, the captain must choose the Outside route. In the worst weather conditions the captain can use the Inside-Inside-Inside route (Princess Royal Channel/Grenville Channel). Other routes are for varying levels of bad weather.


#54

Yes, the weather software is huge, I haven’t been in any significant bad weather for the last 10 years. Good speed helps.

Don’t know if you have access to the high-sea text forecast or not but I sometimes find it helpful to use the weather software to figure out the text quicker. I mouse over each high/low on the computer to read the lat/long then mark up the appropriate part of the text. Just to keep that wx info path open.

Also I make sure I can download via FTP from time to time to make sure that path works.

Knowing the rolling and wave period is sometime useful in cases where a decision has to be if it’s going to be OK to stop for a repair in rough seas.

One time we stopped for a main engine repair on a break-bulk freighter in a good chop near the Azores. Captain wanted to keep running at reduced speed but I figured with a 12 sec roll period it wouldn’t roll much in maybe 12-14 foot 8 sec beam seas. It was rolling a little but not enough to put a hurt on the job and the repairs went quick with no problems.

Exhaust valve replacement on a medium-speed.