When do you put out the Drogue?

[roverhi]

Dragging a drogue has three big advantages, it slows the boat down so, in most instances, won't bury the bow and pitchpole at the bottom of a wave. The second is that it keeps the stern to the seas so you aren't caught broadside and rolled. Third, the crew is below decks, relatively safe and not subject to extreme winds, spray and chill. Probably the best option for a short handed cruising boat crew with limited experience on the helm. You may get pooped occasionally but the boat will survive. Biggest issue is going to be chafe on the drogue line. Many reports of the drogue being lost to chafe when it was most needed.

Racers do stupid and crazy things to win and have plenty of crazy bodies on board to do it. They can cycle through helmsman to limit fatigue and stay on top of steering the boat so it doesn't accidentally get rolled or pitchpole. Not an option for the shorthanded/solo sailers.

Moitessier was running before a monstrous southern hemisphere low pressure that lasted for several days. The boat was riding as well as could be expected but was constantly being overtaken by the waves and getting pooped. Moitessier who had lost two boats, sailed most of the way around the world, and conducted a sailing school in the Med. for a couple of years was way more experienced than most and relatively young. 'Joshua' was literally built like a pressure boiler and probably would have survived anything the sea threw at it as long as the hatches stayed on. He'd set the boat up with an inside steering station so he wasn't sitting outside at the mercy of hurricane force winds, wind driven spray, solid water and wind chill. He decided to surf through the storm but that required him to be on the helm for more than 30 hours through at least one night. I think he got lucky because the concentration required to maintain his heading relative to the waves, especially with limited visibility at night, says more about the directional stability of the boat than the Herculean effort needed to steer the boat minute by minute in mountainous seas over more than a day to meet the challenge of the waves.

In the case of the boat in this post, a drogue may have allowed the boat to go through the wave without being thrown on it's side, injuring the owner, and flooding the boat. Then again, nothing short of a miracle might have prevented the damage. We are talking about a 28,000# boat designed and built to survive these conditions. A rogue wave that could be as much as twice the height of the prevailing storm waves is something that luck has as much to do with coming out relatively unscathed as any technique the skipper took to run through the storm.

[arsenelupiga]

I go with drogue & rum and keep speed 5-10 kn most of time. 2-4 seem too slow.

Force of waves is greatly reduced. You also have some chance to avoid worst parts of hole or valley like one described in article.

[Snowpetrel]

The two times I've run with drogues I've found the steering was kind of weird. The boat certainly didnt want to just trundle along dead downwind.

She really wanted to put the seas on the quarter, then the drogue line would end up 45 degrees off dead downwind and it would pin her at that 45 deg angle. So you would have to kind of gybe and get the boat back downwind of the drogue.

I havent used a series drogue, but I think the extra drag would help keep her running true.

Hook up a towline on a bridle from the back of an outboard dinghy and youll get a feel for what it was like.

[El Pinguino]

When I was smacked in late January or early Feb we were running quite happily with the general wave train and no drogue when a breaking sea...which I never saw coming as I had my back to it.... appeared maybe 45 degrees on the quarter....and yes it was sitting on top of an already quite substantial sea... don't know how a drogue would have helped...

[Lizzy Belle]

Originally Posted by Snowpetrel

^^^ about1400 feet should do it. Ive been on an 800 foot container ship that fell down the mine into a big hole.

True enough, but I was asking about sailboats, not container ships

[boatman61]

Originally Posted by DumnMad

This guy appears very capable and experienced but still got caught by a rogue wave.
Maybe the real problem was his boat was too short for these out of season conditions.

Sailors rescued from crippled yacht - national | Stuff.co.nz

So good they survived to tell the tale

**** happens and its not possible to say why it did.. skipper down below.. inexperienced crew topside.. pushing on instead of heaving to..??
As to the size.. methinks that's a knee jerk irrelevance.. if a Zodiac was the 'rescue vessel' to disembark the crew..
Its just down to bad luck if your sitting in the bottom of the pan when it lands..
Glad everyones safe and injuries superficial..

[thinwater]

Originally Posted by Snowpetrel

...Another time was sailing a S&S34 from hobart to bluff. Building westerly, great sailing but as the wind built we kept reducing sail. very suddenly it went from fun to scary. the sea changed and you could hear them breaking like distant thunder. She started sliding down the faces kind of sideways. We quickly dropped the 3rd reefed main and ran under a scrap of headsail. The seas kept building, and it got darker as the sun set. We set the drogue and then later a long warp when the drogue kept jumping out of the water. It was a rather uncomfortable night. wave must have been at least 100 meters long as the drogue line was 60 meters and it was only half way to the breaker behind us. We didn't get knocked down, luck? or did we set the drogue early enough? Not sure...

Why only 60 meter? True, Seabrake only recommends 3 boat lengths, but that is the minimum on the instruction card and is really a reference for emergency steering and crossing bars. All drogue manufactures recommend 10+ boat lengths, in part because the length helps keep the rode down and in part to get the drogue on the other side of the wave.

I'm assuming it was a GP24L?

[boatman61]

Its my understanding the optimum minimum is two waves behind the boat..

[Snowpetrel]

Originally Posted by thinwater

Why only 60 meter? True, Seabrake only recommends 3 boat lengths, but that is the minimum on the instruction card and is really a reference for emergency steering and crossing bars. All drogue manufactures recommend 10+ boat lengths, in part because the length helps keep the rode down and in part to get the drogue on the other side of the wave.

I'm assuming it was a GP24L?

That was the length of the climbing rope we had. We mistakenly thought the stretch would be a good thing... and 60 meters seemed like plenty of rope.

It was actually a sea squid, a plastic copy of the smaller plastic seabrakes , pre fabric seabrake days. Even with a chunk of chain on it the seasquid was flying 10 or so meters through the air as it broke free of the water.

Many mistakes. Should have had a non stretchy line at least 150-200 meters long. And much more chain.

The next time I ran one it worked much better.

[Snowpetrel]

Originally Posted by boatman61

Its my understanding the optimum minimum is two waves behind the boat..

That would have needed about 250-300 meters of rope in my case.

[arsenelupiga]

Originally Posted by Snowpetrel

That would have needed about 250-300 meters of rope in my case.

i have 125 m of 20mm nylon for this purpose. This gives 60 m long loop where anchor, chain etc can be deployed.

You say no good

[boatman61]

It could be I am totally wrong on this, however..
If just one wave behind this can allow a 'sag' to develop as a wave passes under while the drogue is sucked forward by the forces of the next approaching wave.. result is a sudden acceleration forward unchecked then the chance of a sudden stopping action at an inconvenient moment.. if the drogue is two waves back this reduces the chances of this happening enormously..
I've yet to see dangerous waves/troughs 100metres apart.. more commonly in a big sea they're 50-60ft crest to crest maximum.. but then I've never been in a Hurricane.. 70kts and 12metres sea's is the biggest I've done.

[Snowpetrel]

^^ This is a table of significant wave heights and average values for a fully developed wavetrain. Its quite scary! Normally fetch and time limits the waves to something much smaller than these values for stronger winds, but just occasionally the dynamic fetch and durations can give rise to these kind of waves. As I understand it dynamic fetch and duration values mean you dont actually need to be in this sort of wind for that long. Eg a strong fast moving system can cause a scenario where the waves are carried over the ocean at a similar speed to the system so wave heights can rapidly build, much faster from the point of veiw of us as a nearly stationary observer would expect from the normal cumulative sea state diagram.

As you can see the wavelengths are getting pretty long for say a force 9, 41-47 knots of wind gives an 11 meter high significant wave height (biggest rogue waves will be potentially 2 to 3 times this height say around 30 meters or so, fortunately very rare..) the average wavelength is around 165meters or 541 feet. So to get two wavelengths worth of warp in a fully developed force 9 sea state youd need around 330 meters of warp, for an average wave. But the wavelengths are pretty variable, so to be safe you would need much more. If it got up to force 10 you would need more like 500 meters!

I think all we can do is stick out lots of warp. Last time I put out about 150 meters (I had a full 220m coil of 18mm three strand polyoleifin ready to go) in a pretty moderate sea state, with a lot of chain, about ten meters of 10mm, and it went much better, than the 50 or 60 meters of climbing rope.

I think thats the genius of the series drogue. Because it divides the drogue over a large area of water its less effected by the wavelength problems that effect a single drogue.

Id be keen to try a multi element drogue oneday, say with a seabrake at the end and a tyre or something better much closer. It might work better than a single element drogue. Evans Starzinger uses something similar as I recall.

[Snowpetrel]

Originally Posted by arsenelupiga

i have 125 m of 20mm nylon for this purpose. This gives 60 m long loop where anchor, chain etc can be deployed.

You say no good

20mm nylon will have much less stretch than our 11mm climbing rope had, and 125 meters is lots more than our 60 odd meters, so it would probably work ok, especially if you use plenty of chain to stop it popping out of the water.

[DumnMad]

I asked the OP question before we had been out of sight of land.
Now having done 2 Tasman crossings and experienced Beaufort 9 & 10 I've come to realise the inertia of a heavy 24t boat does make the need for a drogue to control surging not so obvious. Waves 10m H and 150m long are not that steep if you are running with them and the breaking tops are only a little bit scary.
My skipper kept us running at 45 degrees + or - with staysail and mizzen in Force 9 gusting 54knots. We had to work the helm quite a bit but skipper seemed to think it was quite a smooth trip. (He's been a fisherman on NZ's West Coast .)