Yachts vs. Rogue Waves...

These kind of waves you can write a book on, but they should not be compared with Tsunami waves. The Tsunami is an underwater wave of very high speed that builds up when approaching a shallow coast. At sea you can hardly see it.

The so called freak waves are built up by a irregular pattern of waves that can happen in a storm. They don´t travel that far and are not so wide, why a warning system only can be a general storm warning. To put it short.

Just recently another cruise ship in the Med was hit at the bridge and the water intrusion made her without control. Riding out a storm drifting sidewaves was not a nice experience, but they managed to regain control.

The latest incident was a 300 m long boat and compared to smaller yachts, she is not riding up on each wave why a hit is harder. Octopus is half the length and should probably got away better. In the past you always had storm shutters of steel on passages, but with bullet proof glass many yachts are sailing without these.

Safest is to avoid this kind of weather, sailing the known routes at the right time of the year.

All yachts made for the ocean should be able to meet any wave without structural damage. But what can happen with breaking waves is that tenders and toys on deck get messed around with and domes over antennas can be washed away. I have also seen a 50m + yacht getting the bow bent, but I think this has also to do with the boat being extended in the stern, changing her ability to ride up on the waves. Normally an extension should be counterbalanced with a bulbous bow, and the opposite, to regain the initial seakeeping. Big ships however are more often extended in a mid section which doesn´t affect the ride in this way.

Gulf Stream Eddy

Most all us know that a northerly wind blowing against a north flowing Gulf Stream can produce some particularly nasty short, steep seas. This is exaggerated where the two opposing forces (wind and current) are at their greatest, and/or in shallow depths. Best get out of the stream when these get real bad.

What is often overlooked is the eddy situation. The further north you go the stream spreads out, and there are numerous large swirling eddies that spin off onto either side. When these swirling eddies collide with 'local spot conditions' very freak waves can be produced that are totally irregular and undefined. Maybe "Norwegian Dawn" came across one of these.

I was introduced to the existence of these eddies back when an 'late to life racing sailor' Phil Weld first tried to discover why he was capsized by an unexpected freak wave. I had wriiten of this incident on another forum subject "Rogue Waves", "In thinking back about the situation, I had made the descision to leave the Chesapeake Bay knowing of an approaching cold front, but not knowing of its intensity. Thank goodness I had figured that we would be out pass the Gulf Stream prior to arrival of the storm. I've come to find out that it's those meandering circular eddies at the irregular edges of the Gulf Stream that can produce some very 'freak' waves in storm conditions. Phil Weld spent 5 days under his inverted racing tri Gulf Streamer off of Burmuda as a result of one of these freaks. He named his next tri 'Rouge Wave'.

On that other tread Gonzo had written, "I've been hit by two rogue waves. One of the NE coast of Brazil while delivering a sailboat to Martinique. We were sailing the trades with maybe 8-10 foot seas when out of nowhere a 30 foot wave made us broach.
The second time was aboard a trawler in the North Atlantic. A Northester had been blowing for about ten days and the seas where about 20-25 footers. I heard what sounded like a freight train, it was a huge breaker. It completely submerged the 85' boat up to the bridge. I was at the stern by the gallows and somehow managed to hold on to a cleat.

Brian added: These waves are such freaks that there is no 'definition' of their shape as there might be with long, maybe overly big, ocean waves.

Gulfstream Rouge

Back in the early 70's I was crew on a commercial dive boat 80' with 9' draft, raised pilot house. We were racing a coldfront across the stream from West End. The seas got huge and the wind picked up to a steady 60 knots. Waves were slamming into the pilot house and breaking over the top. The 13' whaler on deck washed away and the 23' Formula we were towing was long gone. I was on watch with the search light on. Then a huge vertical wall of beautiful blue water. Then we were underwater and the water pressure hurt your ears. Next every window in the pilot and the aft doors house were blown out from the wave. Water in the boat up to our bellies. I thought we were going to the bottom. The boat shuddered as it surfaced. It felt like trying to hold a basket ball underwater with one hand. It was a good boat I guess. The captain had lots of glass sticking out of his face and head. Blood everywhere. Then in the distance we saw an SOS from a searchlight. We headed over but found nothing and all of our electronics were ruined. So we could not call on the radio. Waves 30ft and breaking white everywhere. North Winds vs. North Current=big steep waves.
Engine driven bilge pump saved the day. It got cold, in the 30's and every wave was breaking into the pilot house. No compass. I could see a planet every once in a while then saw Ft. Pierce the next afternoon. A very long cold night. A yacht would have not done as well. I think the wave must have been over 50 feet high. It broke over the entire boat. Like most sea stories "I swear this is true"

That story seems hard to invent, but I am curious as to how the motors continued in operation after they were submerged. I take it they quit but you were able to get them started again?

Clogged filters

I may have given the wrong impression. The boat was submerged. The engine room stayed fairly dry only about 3 feet of water over the floor boards. This was a commercial fishing boat and not a yacht. Sea Scanner had pneumatic start. The filters clogged several times and we ended up with socks over the racors as a primary. It was a scary time. I've taken up white uniforms and the ICW. Just finished doing my 6th liscense renewal and this was the worse waves I have ever seen.

do you design

Hi Brian,
do you design Yachts ?

When I was a kid, we walked to school, 20 miles, up hill in both directions in 10' of snow while....oops, wrong thread

Which brings up the question: what would the optimum length be for surviving extreme waves. (Assuming something less than a battleship.) Or rather than length should the concern be the length to freeboard ratio?

Just to stir the pot, there was a post on another site about how 100' MYs can snap like sticks. That post was by a trawler fan, who made no bones about not being a fan of stylish yachts. On the other hand I have also read that yacht type trawlers are something of a deception, as they are much lighter than a commercial trawler with its hold full of fish. Not trying to take sides on any of these statements, just showing the range of confusion out there when it comes to sea keeping.

Kelly Cook

Just came across this article. 27 metre wave. What I found interesting is that they calculate the height by using the water pressure beneath the wave.

http://news.bbc.co.uk/1/hi/sci/tech/4739741.stm

Another true sea story

Many years ago I was on 40 ft steel cruising yacht that got caught out in Bass Strait. On more than one occasion we were dropped off a wave which blasted paint off the hull, some of which we found near the masthead several days later when we got into port. I don't know how big the waves were, seemed like 100 feet at the time but they were probabely 25 or so but steep and sharp. I do remember hearing about a ship that was in the same storm that suffered major structural damage. I guess the point that I would like to make is that while a smaller boat may be more uncomfortable it's survivablity may be a little better, but a lot of luck, knowledge and skill comes into play.

Nasty pieces of water

There are many nasty pieces of water around the world, Bass Straight is definately one of them. Shoals, strong currents and at times strong breezes, I have been through the straights under sail 6 times twice it was glassy calm 3 times it was a nice sail and the other time we got the absolute s@#$ kicked out of us. Kind of similar to my experiances with Cape Hatteras.

WHOA!

Is that real, or PhotoShop?