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#16 | |
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I am still trying to imagine how a sailboat could have any effect on breaking ocean swells that weigh hundreds of thousands of times more by putting the swells on the boats quarter thus creating some leeway generated turbulence. I don't doubt it is possible because I am trying to keep my mind open but the concept totally evades me. As far as dumping oil...that makes sense. Oil would absorb energy at the oil water interface plus affect surface tension of the water, both causing a dampening effect. It's an old mariners trick. ![]() I'm not saying anyone is right or wrong...I am just trying to understand the concepts.
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David Last edited by David M; 18-02-2008 at 09:30. |
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#17 |
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Location: Belleville, Ontario, Canada; Playa Zaragoza, Isla de Margarita
Boat: 1994 Solaris Sunstream 40 'Estrella del Sur'
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David, if that were the only reason I might agree. Although locking your helm on the centre-line is no easy matter if your boat is being forced backwards and slewing somewhat to the side in breaking waves. Certainly I would not rely upon the standard brake in an Edson pedestal, for example. Even with hydraulic steering/lashings, the forces generated would eventually create some play that would only exacerbate the situation, leading to even greater forces as the rudder moves off the centre-line.
While to you this seems crazy, there are some sound reasons for the series -drogue. At its simplest, they work because boats tend to have greater lift from the stern than the bow, and because boats are designed to move forwards rather than backwards. Brad |
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#18 | |
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For us the thought of towing a drouge when running off is frightning. The loads impossed on the steering gear would be very high. I would rather not tow anything and let the boat run under bare poles. Wave trains move at what 15 knots or so? As long as we have room that is our game plan. Each and every boat needs a way to deal with weather, strategies may be different from boat to boat though. |
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#19 |
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Location: Belleville, Ontario, Canada; Playa Zaragoza, Isla de Margarita
Boat: 1994 Solaris Sunstream 40 'Estrella del Sur'
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Joli, I couldn't agree more. One word of caution about running with a storm, however: despite the experiences of Dumas, Moitessier and others, it requires a great deal of sea-room and if things get bad enough, there is a very real risk of pitchpoling, even in a well-designed and constructed yacht (read the Smeetons 'Twice is Enough', if I remember the title correctly). At some point you may have to slow the boat down, and that is where drogues and sea-anchors come into play.
Brad |
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#20 |
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This is amounting to naval architects designing steering systems that can handle 99% of the situations that a boat will encounter. I don't know if there are economic reasons for this but there probably are as with all things. Would it take that much more money (and weight increase) to increase the scantlings and design of a steering system so that a yacht can go bow into breaking ocean swells with a nicely locked up rudder? Storms are a part of life for a mariner. It would not take Hercules to turn a rudder with a 60/40 balance even if going backwards at a few knots.
Just curious, at roughly what length does a sailboat need powered hydraulic assist to steer? In seascouts we had a 104 foot twin screw powerboat that had human powered cable steering. Old sailing ships had human powered rudders of course, but in all practicality, how about modern sailing vessels?
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David Last edited by David M; 18-02-2008 at 09:49. |
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#21 |
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This is a tough 'armchair' question. We've all read what works for different folks. I would imagine you pick the story with the boat that most resembles yours and hope for the best.
As for catamarans, I believe the definitive story is the Queen's Birthday storm. Lie ahull, get yourself tied down in the salon and hold on until the ride is over. However, this advice is of little use when there's the possibility of a lee shore. |
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#22 | |
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David |
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#23 |
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Location: Belleville, Ontario, Canada; Playa Zaragoza, Isla de Margarita
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David, hydraulic steering is often installed on vessels that do not require 'power' assist. My Cartwright 36 pilothouse had it because it is ideally suited to multiple steering stations. The boat herself, however, was extremely well balanced and could be steered easily with the hydraulics off and the emergency tiller in place.
Hydraulic steering is also used on my cat, again not because the vessel requires a 'power assist', but because it is also ideally suited to having one wheel operate two rudders. Properly engineered hydraulic steering systems may reduce 'feel' (less relevant in a catamaran anyway), but they are both extremely strong and reliable (and certainly more so than the ubiquitous cable systems used in so many boats). Is there a point at which hydraulic steering becomes a necessity? No doubt, but that would no doubt be contingent upon the anticipated steering forces more than length overall, or displacement. In any case, it is bound to be on a boat much larger (or much more poorly balanced ) than I would ever own. Brad |
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#24 |
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#25 |
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I think we need to differentiate between Multis and Monos. They obviously quite different machines and react very differently in the water. From the literature I have seen, a series drogue appears to make a lot of sense for a Multi. I am not so sure about a Mono, and the rest of the post refers only to my thoughts on Monos.
I agree with the comments about para anchors possibily collasping and putting large stains on rodes, anchor points etc. The Pardey's go into some detail about the length of rode in relation to wave lengths etc to keep the para anchor "filled". This would need to be monitored as conditions change. I have a few concerns about series drogues for a Mono. With a stern drogue, the boat is still sailing downwind and needs to be steered (manually or otherwise); in essence you are still underway and require more input (and energy) from the crew to sail the boat; you are using up searoom at a much faster rate; you are probably travelling with the storm thus prolonging your exposure. A drogue does not alter the sea state and breaking seas still have to be contended with. Likewise the risk of broaching, while reduced, is still present and this threat increases as fatigue increase. A para anchor set from the bow seems to have significant inherent risks also. Most are already mentioned by others on this thread. Hove to (under sail / rudder angle alone) seems to be OK except for the risk of breaking seas - and to me that seems to be a very significant risk from the handfull of breaking seas I have seen in the Tasman sea. I am assuming the design of the boat allows it to be hove to satisfactorly. However setting a para anchor on a running bridle from the bow and quarter while hove to seems to overcome most of the risks providing the boat can be kept inside the protection of the slick and the postioning of the para anchor is maintained relative to the wave length. Yes, that will require monitoring and so will chafe issues but the boat is now (supposedly) free from the threat of breaking seas, capsize, pitchpoling, riding the seas comfortably, not underway, fairly stationary while the storm is moving away and in general, providing a safe haven for the crew to rest in. The key to the whole thing appears to be the existence and effectivness of this "slick" - to prevent the seas immediately to windward from breaking. I know some of you doubt it effectivness - and I doubt it a bit too - but although I don't understand (yet) how it works, I am starting to believe it must, if significant sailors report that it is true. Sounds to be good to be true doesn't it. That is why I keep asking for first hand experience to confirm (or otherwise) the theory. So far, the only first hand accounts I have found are the Pardey's. I may be able to post my own experiences here one day as I am planning to experiment with this (in a safe manner) as soon as I am back on the water. Thanks to Irwinsailor for starting this thread and to everyone else willing to share their thoughts and time so far. ![]()
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All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence |
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#26 |
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BTW I don't mean to make any significant storm sound trivial, I am aware of the awesome power of nature - I am just trying to find the best possible way to prepare for such events. The outcome depends on foresight, preparation, knowledge and God.
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All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence |
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#27 |
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Wotname, when fully deployed the Jordan series-drogue slows the boat to 1 1/2 knots (approx.) and does not require any steering imput. As to sea room, boats with properly deployed para-anchors will also drift - you cannot overcome the effects of current.
Brad |
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#28 |
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Thanks Brad, I wasn't aware the series drogue would allow the boat to "self steer" and not require some helm input. Must have missed that bit in my reading. I can sort of see how it might work - a big arm keeping the stern of the boat to windard as it sails downwind very slowly.
Pardey's experience seems to suggest 1/4 to 1/2 knots of drift - and I realize this will depend on boat design etc. But that is still at least 3 times slower. Again we are talking speed through the water due to wind forces acting on the boat. Current will have the same effect on searoom using either system. There are still the concerns of reducing the prospect of breaking seas around the boat and the general stability of a boat hove to compared to a boat still making way downwind. I am talking Monos again as they can roll substantially when running (even running slowly). I can't see (yet) how a series drogue would prevent such rolling.
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All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence |
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#29 |
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The Pardey's have a DVD called Storm Tactics that shows what they are talking about. I have watched it several times and tried heaving to once in 40kts of wind with 12' white caps on lake Michigan. The slick was there and the boat rode very well just as it showed in the DVD.
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Gunner |
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#30 | |
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