Storm Tactics

[Whimsical]

One thing that always seems to be missing in the debate as to which device to employ, parra or drouge, is the position of the vessel in relation to the storm. If I was in the quadrant where running off would follow the track of the storm then I would use the anchor. Conversly if in the other quadrants then running off would shorten the dance with the devil so thats the way I would go.
Searoom may alter the decision however.

Mike

[Southern Star]

Mike, I would agree that trying to be in the correct quandrant of a storm as it approaches is extremely important. This is imprecise, of course, as storms rarely stay to a constant or predicted course. Furthermore, the required direction of travel (typically to the west in the northern hemishpere, east in the southern) might cause you to head towards shore, reducing available searoom and putting you over a shoaling (or at least shallowing) bottom: this would only worsen your prospects once the storm hits. If you have the sea room, then by all means you should sail away from the most lethal part of the storm.

Having said that, once you are in the storm and are at or approaching survival conditions (what we are talking about here), running off will require constant attention to the helm and increase the risk of pitchpoling.

There are many proponents of high-speed scudding, or running with a storm - Dumas and Moitessier being perhaps the first to write about it in the context of a yacht. Due to the requirement for constant and fastidious attention to the helm, Vigor recommends this tactic only if your boat is being overwhelmed streaming drogues, or setting to a sea-anchor. Indeed, even Moitessier attempted the technique only after he had deployed drogues and found that (eventually) the cockpit was being repeatedly barraged by breaking seas. We must also remember that he was obviously in the wrong quadrant as he remained with the storm for a couple of days - an awfully long time for a short-handed crew, even in good conditions.

So yes, scudding makes sense if you are in the correct quadrant, have searoom and adequate rested and capable crew. On the other hand, there is good sense in attempting a passive tactic as a first line of defence. This will allow the crew an opportunity to adjust to the violent motion, sounds and yes fear while maintaining their strength should scudding become necessary.

Brad

[Robertcateran]

To avoid the problem of what to do if the drogue is in adequate fro the conditions, have a boat that is set up for having the parachute from the rear,
Robert

[Wotname]

Paul L & Ssullivan,
I am not sure I can agree with the explanations of what causes a problem with storm created waves. I think we have to distinguish between what happens when a boat is safely hove to and when it is in danger of capsize / broaching / pitch poling etc.
Again I am only considering mono's (because I dont know anything about multi's).

Hove to (with or without para anchor set): From my understanding of the Pardey's Storm Tactics, the keel is ~ 50 degrees off the wind (and waves) due to being hove to. The water is then flowing sideways around the keel. This causes turbulence to the surface layers of the water in the wave system. As the boat is pushed sideways downwind, the disturbance appears to move to windard (but really is stationary). Before it dissipates, it has sufficent affect on the approaching wave to modify surface flows in the wave to prevent it breaking dangerously. This is the slick they refer to and how it prevents the crest of the approaching sea from breaking in the vinicity of the boat. The reason the keel shape is considered is because different keel shapes will affect how stationary the boat remains relative approaching seas. The boat must stay directly downwind of this slick and not fore reach out of this protective area. A full keel will remain more stationary then a fin keel but most fin keels should be able to be kept stationary with a bit more effort in considering sail area, sail position and tiller position. The para anchor when set off a bridle and kept directly upwind while the boat maintains ~50 off the wind helps to hold the boat stationary w.r.t. the slick. It also creates some disturbance to the surface layers itself and thus assists in modifying the wave crests even further upwind.
BTW this won't happen if a para anchor is set directly from the bow. The para anchor will try to pull the boat out of the hove to position thus will present its keel directly into the wave system and not create any turbulence. A fin keel boat will still sail around a bit and be exposed to breaking seas on its fore quater or even its beam - not good.

However very different things happen if there is no "protection" from this slick. As I understand storm conditions, the danger comes from large breaking seas overpowering the boat. Not the type of breaking crests where the water is simply flowing down the front of the wave like a giant white cap. Rather large curling or overreaching seas more like large surf breaking on a shoaling shore. These breaking seas will typically fall onto the lee side of the boat (hove to - out of the slick - or lying ahull). The boat is damaged with tons of water falling onto it. The wind has the boat already heeled, the lee deck is pushed further under by the breaking sea, the circular motion of the surface layer of the wave is pushing the keel up to windward and the boat is at least knocked down if not rolled right over. From my reading, most damage occurs to the lee side of the boat.
Slighty different mechanics occur if broaching but the end result remains the same. Again different mechanics with pitch poling and even worse outcomes.

The above is simply my limited undertsanding of the dymanics of the seas and mono's in storm conditions concluded from reading every account I can of the same and some rather limited sea time in winds over 40 kts. I am very happy to consider other explanations and to be proved wrong in any of my assumptions.

[David_Old_Jersey]

Originally Posted by Wotname

However very different things happen if there is no "protection" from this slick. As I understand storm conditions, the danger comes from large breaking seas overpowering the boat. Not the type of breaking crests where the water is simply flowing down the front of the wave like a giant white cap. Rather large curling or overreaching seas more like large surf breaking on a shoaling shore. These breaking seas will typically fall onto the lee side of the boat (hove to - out of the slick - or lying ahull). The boat is damaged with tons of water falling onto it. The wind has the boat already heeled, the lee deck is pushed further under by the breaking sea, the circular motion of the surface layer of the wave is pushing the keel up to windward and the boat is at least knocked down if not rolled right over. From my reading, most damage occurs to the lee side of the boat.
Slighty different mechanics occur if broaching but the end result remains the same. Again different mechanics with pitch poling and even worse outcomes.

The above is simply my limited undertsanding of the dymanics of the seas and mono's in storm conditions concluded from reading every account I can of the same and some rather limited sea time in winds over 40 kts. I am very happy to consider other explanations and to be proved wrong in any of my assumptions.

I too am struggling to understand the dynamics of all this......

The Pardey storm anchor approach seems to be an enhancement of hoving to - which I have tried on previous boats (just for fun / to see what happens / make lunch ) and found it worked great - albeit for me not in any weather where I actually needed to do so. I reckon the slick "works" because water goes for the route of least resistance - but I stand to be corrected!

My thinking is that if hoving to works well in "normal" bad weather, then the Pardey Storm Anchor hoving to approach will work well in "badder" bad weather .......but when (gawd forbid!) in a situation where green waves are breaking over the boat (like surf waves) then my gut tells me I would want the bow directly facing these breaking waves and not to be lying abeam or even having only a fore quarter facing the breaking waves..........even if the price to be paid is the loss of the slick that makes life more comfortable for "normal" waves. (from my attempts at surfing many years ago I am well aware that their is an awful lot of (dynamic?) power in breaking waves - as well as simply a lot of weight!).

Am not planning to test any of this anytime soon

[Ramona]

Originally Posted by David_Old_Jersey

my gut tells me I would want the bow directly facing these breaking waves and not to be lying abeam or even having only a fore quarter facing the breaking waves.

Directly facing the waves is not a good idea. Even with moderate sized waves you can find your self airborne and falling into the trough. I have done this in my 40 foot fishing vessel and it hurts.
Up the waves at an angle and down the other side the same is the optimum.

sneuman, thanks for your write up. It is helping me decide on my next yacht.

[CharlieCobra]

Originally Posted by David_Old_Jersey

I too am struggling to understand the dynamics of all this......

The Pardey storm anchor approach seems to be an enhancement of hoving to - which I have tried on previous boats (just for fun / to see what happens / make lunch ) and found it worked great - albeit for me not in any weather where I actually needed to do so. I reckon the slick "works" because water goes for the route of least resistance - but I stand to be corrected!

My thinking is that if hoving to works well in "normal" bad weather, then the Pardey Storm Anchor hoving to approach will work well in "badder" bad weather .......but when (gawd forbid!) in a situation where green waves are breaking over the boat (like surf waves) then my gut tells me I would want the bow directly facing these breaking waves and not to be lying abeam or even having only a fore quarter facing the breaking waves..........even if the price to be paid is the loss of the slick that makes life more comfortable for "normal" waves. (from my attempts at surfing many years ago I am well aware that their is an awful lot of (dynamic?) power in breaking waves - as well as simply a lot of weight!).

Am not planning to test any of this anytime soon

What the Pardeys found was that when hove to with the para anchor, the breakers seemed to collapse onto the slick before they reached the boat and the only thing that hit the boat was foam. IIRC they watched for a long time to see exactly what the big breakers were doing before going below.

[David_Old_Jersey]

Originally Posted by CharlieCobra

What the Pardeys found was that when hove to with the para anchor, the breakers seemed to collapse onto the slick before they reached the boat and the only thing that hit the boat was foam. IIRC they watched for a long time to see exactly what the big breakers were doing before going below.

It occurs to me that it takes a certain type of person to sit in the middle of a gale and say to themselves "lets try something completely new and untried".

I have been thinking .........could a Para Anchor be deployed from the stern? with the boat then held at the 50 degree angle - it would save having to turn the vessel.......of course would need strong points at the stern!

Anyone want to try it out in a Force 10? (just to satisfy my curiosity )

[Charlie]

The Jordan Series Drogue is one of the ideas that I would want to use in the case of a Typhoon or Hurricane. The Drogue was studied by the Coastguard. It was designed after research on the '79 fastnet race fatalities. But I think that one has to look at their tactics in light of a few consideration including: type of keel, shape and height of waves, amount of wind. I don't have experience in a storm like SNueman but I think that having multiple methods for surviving a storm is the key. Heaving to, running off, series drogue, and using your brain.

[Southern Star]

Dan, regardless of the 'slick', deploying a sea-anchor from a bridle off the bow/side deck is still a very effective approach to storm management for many yachts.

Brad

[dacust]

Originally Posted by Southern Star

Dan, regardless of the 'slick', deploying a sea-anchor from a bridle off the bow/side deck is still a very effective approach to storm management for many yachts.

Brad

Oh, I'm not argueing with that. I'm only talking about the slick and the claim that it can stop waves from breaking because of the way it disturbs the water.

[mjt]

Originally Posted by dacust

Oh, I'm not argueing with that. I'm only talking about the slick and the claim that it can stop waves from breaking because of the way it disturbs the water.

Apart from the lucid and detailed account given by the Pardey's in their book, the best motivation I have for believing that the slick induced by a hove to boat can stop breaking waves is this simple experiment:

Get in your dinghy in windy/choppy conditions. Row along and watch the behaviour of the vortices (swirls) left by your oar strokes. The vortices stop wavelets and are so stable that often you can count as many as twenty oar strokes receding into the distance behind your dinghy.

That stability and ability to break up waves comes from the momentum of the vortices. It is a smaller scale version of the combined effects of a hove to keel and a large parachute anchor which will induce swirling in the sea, making a nice stable slick/pathway which helps to destabilise breakers and keep your boat safe.

[Wotname]

Originally Posted by mjt

...
Get in your dinghy in windy/choppy conditions. Row along and watch the behaviour of the vortices (swirls) left by your oar strokes. The vortices stop wavelets and are so stable that often you can count as many as twenty oar strokes receding into the distance behind your dinghy.

That stability and ability to break up waves comes from the momentum of the vortices. It is a smaller scale version of the combined effects of a hove to keel and a large parachute anchor which will induce swirling in the sea, making a nice stable slick/pathway which helps to destabilise breakers and keep your boat safe.

Excellent observation, thanks for the input, it helps to understand the dynamics even if I still don't know the science behind it.

[Wotname]

Originally Posted by dacust

Oh, I'm not argueing with that. I'm only talking about the slick and the claim that it can stop waves from breaking because of the way it disturbs the water.

Revisiting the thread as the OP was reading L & L's Storm Tactics. Their third edition arrived today and I will have to get off CF and start reading this new updated edition.

The first gem was referring to the "slick" as a Von Karman vortex street (try a google search for more info).

[Nauticatarcher]

The best storm tactic is good weather forecasting and avoidance, with modern forecasting techniques and the ability to receive them on board its just about possible to sail around anything, do you go for the fence at the top of the cliff or the ambulance at the bottom