Yacht sinks off Bay of Islands in 40knots

[daletournier]

Originally Posted by CassidyNZ

During our severe weather event we had no drogues and at one point we’re running under bare poles too. Still the boat speed went up to 9kn at times and in the dead of night the boat took off down a wave. Scared me more than any other thing in my sailing life up to that point. My experience with bare pole sailing is that your choices of direction are quite limited.

I think the choice of size of drogues is important. Something too big (like some of the parachute anchors I have seen) would probably more stop the boat than slow it and that would not be my goal. This is all speculation on my part because I’ve never deployed a drogue as a survival tactic but I have deployed mine while motoring at 8kn. It slowed the boat to about 4kn and held it there which is I guess technically what it would do in a serious weather event.

Remember, swells run by a sailing boat at a much greater speed than boat speed and the combination of boat speed and the steepness of the swell are what would start a boat surfing. Remove either element and surfing won’t happen. That, to me, is the key - stop the boat surfing and you’re reasonably able to survive. And in my “tests”, it didn’t take a very big drogue to reduce boat speed sufficiently. FTR, my drogue is a meter diameter, steep sided cone (not umbrella) with a 400mm outlet downstream.

I've thought a small drogue would be better, just knocking a couple of knots of , speed limiting, I dont think that much is needed.

I agree bare poles isnt best but it worked quite well, my spade rudder is large and powerful I also engaged the Hydrovane as well ,big and small rudder working at the same time....what ever works.

[fxykty]

There’s also the issue of the breaking portion of a wave accelerating a boat. This has much greater force applied much more quickly to the boat than either wind or gravity. A single element drogue can get overwhelmed and release in those conditions - hence the development of the series drogue.

If you want to stop (lee shore, you need rest, etc), and your boat lies well to an anchor (doesn’t commonly yaw or hunt when anchored to the bottom in high/gusty winds), then your best bet is a sea anchor (aka parachute anchor) deployed off the bow. Parachutes are reputed to break the seas in front of you (essentially a submerged reef) and can work even in ultimate storms. You definitely need strong points near your bow and a way to reduce chafe.

If you want to keep moving and only want to limit surfs then a single element drogue will work as long as you’re not moving too fast and the waves aren’t too steep and/or breaking. But at some point the single element drogue will no longer limit your top speeds and may even break out and stop working.

A series drogue may be required if you don’t or can’t use a sea anchor but find yourself in an ultimate storm. It also essentially anchors you as it limits boat speed to 2-3 knots. In addition to strong points and reducing chafe at the stern, you also need to be sure that your stern, cockpit, companionway and/or door(s) can withstand breaking green water.

[JAFO]

Originally Posted by fxykty

Parachutes are reputed to break the seas in front of you (essentially a submerged reef) and can work even in ultimate storms. You definitely need strong points near your bow and a way to reduce chafe.

Parachutes also have the problem that they need tuning to the wavelength of the seas to be effective. The parachute needs to be situated one wavelength away from the boat. So as a storm progresses, there's a good chance you're going to have to go forward on deck to adjust the length of the bridle, right when you'd really be better off staying below. Series drogues don't suffer from this issue.

[CassidyNZ]

Originally Posted by JAFO

Parachutes also have the problem that they need tuning to the wavelength of the seas to be effective. The parachute needs to be situated one wavelength away from the boat. So as a storm progresses, there's a good chance you're going to have to go forward on deck to adjust the length of the bridle, right when you'd really be better off staying below. Series drogues don't suffer from this issue.

Again, the import of your posts is that you’re using a drogue/chute to stop your boat. I would (I believe) never do that and hence would never stream such a device from the bow. In order to keep moving, drogues, etc would be streamed astern. I have two very strong, smooth fairleads on the aft deck that completely eliminate chafe.

Oh, and tuning the line length to the wave period is apparently important with all such devices. The drogue wants to be buried under the wave behind the one that’s threatening you.

When I was a lot younger and reading sailing books by the legendary Eric Hiscock, he purported to use an oily rag draped over the stern or weather rail, dripping oil into the sea and claimed it made a substantial difference to the aggression of approaching seas. I shall try that one day (despite the fact that I may be polluting the oceans).

[CassidyNZ]

Originally Posted by fxykty

There’s also the issue of the breaking portion of a wave accelerating a boat. This has much greater force applied much more quickly to the boat than either wind or gravity.

That’s why slowing the boat is important to me. Firstly a boat that’s doing 3 or 4 knots will not accelerate as easily as one doing 9kn. Also, running with the seas presents a narrow target for white water also reducing the acceleration potential

Originally Posted by fxykty

Parachutes are reputed to break the seas in front of you (essentially a submerged reef) and can work even in ultimate storms. You definitely need strong points near your bow and a way to reduce chafe.

I assume you mean diffuse the seas and if so that’s a good thing. But I wouldn’t want any device that turns forty feet of green swell into ten feet of white water

Originally Posted by fxykty

In addition to strong points and reducing chafe at the stern, you also need to be sure that your stern, cockpit, companionway and/or door(s) can withstand breaking green water.

I have two large, smooth fairleads on the transom that all but eliminate chafe. And a centre cockpit that keeps unruly white water at bay.

[fxykty]

Originally Posted by CassidyNZ

That’s why slowing the boat is important to me. Firstly a boat that’s doing 3 or 4 knots will not accelerate as easily as one doing 9kn. Also, running with the seas presents a narrow target for white water also reducing the acceleration potential







I assume you mean diffuse the seas and if so that’s a good thing. But I wouldn’t want any device that turns forty feet of green swell into ten feet of white water







I have two large, smooth fairleads on the transom that all but eliminate chafe. And a centre cockpit that keeps unruly white water at bay.

Diffuse yes, not surf, but only based on what I’ve seen reported and on sites like Coppins, a manufacturer of parachute sea anchors.

Regarding fairleads, even smooth surfaces will chafe as the friction creates heat. If you’re using a non-stretch UHMWPE line through the fairleads you’re OK but if you’ve got polyester or nylon it will chafe in storm conditions. Best is if you have a clear run from your chainplates or cleats to your drogue, with no fairleads needed. Hence why folks will mount chainplates on the outboard sides of their stern(s) and protruding beyond the stern.

[JAFO]

Originally Posted by CassidyNZ

Again, the import of your posts is that you’re using a drogue/chute to stop your boat. I would (I believe) never do that and hence would never stream such a device from the bow. In order to keep moving, drogues, etc would be streamed astern. I have two very strong, smooth fairleads on the aft deck that completely eliminate chafe.

Oh, and tuning the line length to the wave period is apparently important with all such devices. The drogue wants to be buried under the wave behind the one that’s threatening you.

Umm.. no.. you presume wrongly. I'm not in favour of streaming a JSD from the bow either. I'm presently designing a permanently ready-to-deploy JSD system with strong chafe-free fittings on the stern for my next boat. Basically, horizontally mounted, oversize chainplates positioned to pull through the centre of mass of the boat. See the image below, of the ones on Roger Taylor's Mingming II for an idea of what I'm going for. Each plate is rated at 120% of the mass of the entire boat. Frankly, I'd like to beef that up to 150% each, which is part of the reason mine will be titanium rather than stainless steel.






And a properly set up JSD is meant to be sufficiently weighted at the end, such that it buries itself to a depth that makes the wave period irrelevant.

[JAFO]

Originally Posted by CassidyNZ

When I was a lot younger and reading sailing books by the legendary Eric Hiscock, he purported to use an oily rag draped over the stern or weather rail, dripping oil into the sea and claimed it made a substantial difference to the aggression of approaching seas. I shall try that one day (despite the fact that I may be polluting the oceans).

It wasn't just Hiscock.. it was a commonly used tactic at the time and was widely proclaimed as effective by all who tried it. However, it wasn't a rag.. it was a bag. Filled with several litres of oil, and with 2 or 3 small holes punched into it. IIRC, the Pardey's use one in conjunction with their parachute drogue.

Originally Posted by fxykty

Best is if you have a clear run from your chainplates or cleats to your drogue, with no fairleads needed. Hence why folks will mount chainplates on the outboard sides of their stern(s) and protruding beyond the stern.

Exactly... just like the ones in my post above.

[Tillsbury]

Originally Posted by JAFO

It wasn't just Hiscock.. it was a commonly used tactic at the time and was widely proclaimed as effective by all who tried it. However, it wasn't a rag.. it was a bag. Filled with several litres of oil, and with 2 or 3 small holes punched into it. IIRC, the Pardey's use one in conjunction with their parachute drogue.

The bag is an old-school solution. Another way with our new-fangled boats is to drip it down the galley sink. I did this in the North Sea once - stuffed an oily rag down the plug and poured oil on top so it slowly dripped down the drain. It really helps a confused sea behind you, it truly needs to be experienced to believe it works. The waves don’t get smaller but they do get smoother and you can see them coming so much better.

[Wotname]

Yes, using oil to calm rough (i.e. breaking) seas seems to be forgotten art. Perhaps because many refuse to believe they can influence the behaviour of large waves that are a 100+ metres upwind.

The Pardeys have tried to get the message out but...

In essence, if the boat is parked (lying to a sea anchor or hove to), the only danger upwind is breaking seas where as the dangers to a moving boat is surfing / broaching / pitch poling / crew fatigue etc (as well as the breaking seas of course.)

If the breaking aspects of the upwind seas can be reduced by the vortices created by a para anchor / large keel / oil, the dangers are reduced.

The physics of why it works are apparently not well understood by the modern sailor.

[CassidyNZ]

Originally Posted by JAFO

Basically, horizontally mounted, oversize chainplates positioned to pull through the centre of mass of the boat. See the image below, of the ones on Roger Taylor's Mingming II for an idea of what I'm going for. Each plate is rated at 120% of the mass of the entire boat. Frankly, I'd like to beef that up to 150% each, which is part of the reason mine will be titanium rather than stainless steel.

Trying not to be picky but seems to me it doesn’t matter how strong the chainplates are, the strength of the attachments will be governed by the shear strength of the shackle pin.

And let’s be fair, those appendages are not pretty and hanging over the back to attach those shackles in a lumpy sea would intimidate me and probably cost a range of tools

Originally Posted by JAFO

And a properly set up JSD is meant to be sufficiently weighted at the end, such that it buries itself to a depth that makes the wave period irrelevant.

The reason I have not considered acquiring a JSD is that I look at the structure and wonder where I would store something that voluminous. Even 100 metres of sturdy rope takes a lot of space, all those little pockets and their tackle added to the line must fill a large space.

[Tillsbury]

Have a read of the articles on morganscloud regarding jsds. Dyneema as a primary line makes it so much smaller and lighter. He also discusses that the limits of the shear strength of the bolts through the stern plates was the limiting factor in most of the designs.

[fxykty]

Originally Posted by Tillsbury

Have a read of the articles on morganscloud regarding jsds. Dyneema as a primary line makes it so much smaller and lighter. He also discusses that the limits of the shear strength of the bolts through the stern plates was the limiting factor in most of the designs.

Yes, Dyneema single braid. And soft shackles.

We’re in the midst of creating a 156 cone JSD with almost 200m of line and bridle. It will fit in a bag 30cm in diameter and 70cm high. Not including the weight, it weighs about 12kg, which is mostly cone weight. Because the Dyneema (actually Acera Amundsen) is so light, and floats, we are planning to double the weight at the end - 40kg rather than 18kg as specified by OceanBrake when using polyester double braid. Not sure whether we’ll use chain or a kellet for the weight.

We’ve built soft shackles to attach the bridles to the boat chainplates. They’re made from 12mm Acera Amundsen and can each take the weight of our boat. No metal hardware anywhere on our JSD except the thimble at the end of the tail to which the weight is attached.

Regarding a previous comment, it is pre-rigged before a passage. Deploying it means lowering the weight over the stern and letting it run out of the bag. No tools or exposure needed.

[JAFO]

Originally Posted by CassidyNZ

Trying not to be picky but seems to me it doesn’t matter how strong the chainplates are, the strength of the attachments will be governed by the shear strength of the shackle pin.

Which is why one should use suitably sized shackles, yes?

Originally Posted by CassidyNZ

And let’s be fair, those appendages are not pretty and hanging over the back to attach those shackles in a lumpy sea would intimidate me and probably cost a range of tools

Hmm.. I wasn't aware that 'prettiness' was a consideration for safety gear. And if you think you'd need to hang over the stern and attach the shackles in a lumpy sea, you're kind of missing the point. The idea is that the shackles are permanently attached, so that the JSD is ready to deploy without any faffing about during dangerous conditions. But I suppose that would be even less pretty.

Originally Posted by CassidyNZ

The reason I have not considered acquiring a JSD is that I look at the structure and wonder where I would store something that voluminous. Even 100 metres of sturdy rope takes a lot of space, all those little pockets and their tackle added to the line must fill a large space.

What Roger Taylor has done is distribute his JSD between two deck boxes at the stern, so it's always ready to go. I plan on doing something similar, although probably using a single larger box.

Originally Posted by Tillsbury

Have a read of the articles on morganscloud regarding jsds. Dyneema as a primary line makes it so much smaller and lighter. He also discusses that the limits of the shear strength of the bolts through the stern plates was the limiting factor in most of the designs.

Thanks.. lots of information to absorb there.. interesting too to see that Dyneema comes with its own set of issues and challenges too.. not least being the need for a heavier weight at the end, and a more difficult recovery afterwards.

[barryglewis]

After moving the liferaft from front end of cockpit (under a lid) to the pushpit we now stow a Jordan series drogue in its place. It takes nearly the same room!
Its also where the aluminium companion way washboards live when not in use.
Chainplates for the drogue are bolted to the toerail which is integral part of the hull, with shackles permanantly fitted. Have clips to connect bridle to shackles. Wish I had gotten a dyneema version of drogue