Chris_Stannard
New member
The controversy over the Legend got me thinking a bit, and I went back to a couple of sources for more information. The study, done on the Contessa 32 and Half Tonner after the Fastnet referred only to the affect of stability on the sail carrying capability of the boat, not to its resistance to being rolled.
The sources I am quoting are Chapter 32 in Heavy Weather Sailing by Adlard coles (1992) edition, the Stability Factor section from Yaching Monthly's publication "The Complete Offshore Yacht". I also refer to the 'Fatal Storm', the book on the 98 Sydney Hobart Race, a book on the Fastnet, whose name I cannot remember but was written by a participant, and the article 'Surviving Heavy Weather' in this month's Yachting Monthly
Both Adlard Coles and the Complete Offshore Yacht have table showing the factors that come into play for stability. I draw on them for the following affects:
A Narrow Beam - improves
the resistance to capsize by a breaking wave,
the angle of vanishing stability,
downwave control which is important if you run off
and reduces the inverted stability so that in the worst case you are more likely to come back quickly.
On the down side it reduces the stiffness and therefore the ability to carry sail.
Displacement - A heavier displacement offers all of the same advantages as a narrow beam but to a less marked degree. It also improves stiffness. Chuck Paine, a well known designer jhad a 20/20 rule for cruising boats. This stated that a cruising boat should be able to carry all plain sail with 20 knots of indicated wind with no more than 20 degrees of heel
Angle of Vanishing Stability. Adlard Coles states that yachts with an angle of vanishing stability of less than 140 degrees can be left floating upside down for a period after inversion. He also considers that the righting moment between 100 and 130 degrees is important in the yachts resistance to capsize.
Most of these factors relate to meeting very severe weather at sea, so that any boat which claims a classification of A should have taken these factors into account.
The trouble is that they conflict with the the floating caravan approach (more beam) in less length, and cost (heavier boats cost more to build).
Using these factors I looked back over a few recent boat tests. These tend to show there are the heavier cruising boats, such as the Najad, Halberg Rassy, Malo etc and the lighter boats that tend to be for more coastal work, since they are lighter and less heavily constructed. On this basis
A comparison of the Dehler 36 with the Legend shows, (Dehler figures in brackets)
Legend 10.8m(11.0), Beam 3.6m(3.5), Draught 1.9m(2.0), Displacement 6305kg(6000), Ballast 2297kg(2200), Sail Area 66.9sqm(71). It would therefore appear that the Legend is not built primarily as a deep water cruiser but is in the same category as the Dehler
Adlard Coles makes the point that stability is not everything, it is only one factor that will increase the resistance to knock down. He also says that although a heavier boat is more likely to be able to withstand a breaking sea she needs to be stronger in order to stand up to the heavier loads that this will impose. He then states:
"THE SKILL AND COMMON SENSE OF THE CREW AND THE TACTICS THEY EMPLOY MAKE THE GREATEST CONTRIBUTION TO CAPSIZE AVOIDANCE"
The heavy weather article makes some interesting points, for example that an area of shallow water in a deep area can create problems. This seemed to be the case in the '78 Fastnet, when most of the trouble occured in the vicinity of the Labadie Bank, where the water shoals from aroung 120 metres to about 60. It also makes the point of low pressure systems being trapped against high pressure systems, and the affect of currents against winds. These are clearly illustrated in the 'Fatal Storm'. The 'Fatal Storm' also illustrates that you need to make ground away from the storm centre and that running across the sea is the worst thing you can do, the sea must either be on the quarter or on the bow.
A further factor that needs to be considered is the strength of the crew and their resistance to bad weather. How long will your crew keep going if it is rough.
When I started to sail, almost 50 years ago, I was taught that you had to plan within the capability of the crew. Thus when my wife and I are sailing together we plan on 12 hours maximum, daylight only and weather forecast of no more than Force 5. This means that we are rarely out after midnight and have yet to be caught by more than a Force 8. We also have a boat that will look after us.
I would not wish to prevent anyone from sailing but when I see stories of a Sadler 32 with a husband, wife and two small children coming through the Needles channel in bad weather, or I remember the passage skipper who was charged with manslaughter of a crew member who drowned when a boat, said by the coroner to be unfit for the purpose, sank in the Bay of Biscay I wonder if this is still remembered.
I would therefore recommend that you define what you want a boat to do, and what skill levels you have available to do it before you start looking at boats. Then get the best for your purpose. And read all you can on other people experiences, it will be too late when the gale starts. When you do get to sea make sure you have thought through all the bad weather what ifs, where will you run to, what happens if you cannot get there and so on. And last of all take action early
I hope this is of interest to some and apologies to all who think I am teaching granny to suck eggs.
Chris
Chris Stannard
The sources I am quoting are Chapter 32 in Heavy Weather Sailing by Adlard coles (1992) edition, the Stability Factor section from Yaching Monthly's publication "The Complete Offshore Yacht". I also refer to the 'Fatal Storm', the book on the 98 Sydney Hobart Race, a book on the Fastnet, whose name I cannot remember but was written by a participant, and the article 'Surviving Heavy Weather' in this month's Yachting Monthly
Both Adlard Coles and the Complete Offshore Yacht have table showing the factors that come into play for stability. I draw on them for the following affects:
A Narrow Beam - improves
the resistance to capsize by a breaking wave,
the angle of vanishing stability,
downwave control which is important if you run off
and reduces the inverted stability so that in the worst case you are more likely to come back quickly.
On the down side it reduces the stiffness and therefore the ability to carry sail.
Displacement - A heavier displacement offers all of the same advantages as a narrow beam but to a less marked degree. It also improves stiffness. Chuck Paine, a well known designer jhad a 20/20 rule for cruising boats. This stated that a cruising boat should be able to carry all plain sail with 20 knots of indicated wind with no more than 20 degrees of heel
Angle of Vanishing Stability. Adlard Coles states that yachts with an angle of vanishing stability of less than 140 degrees can be left floating upside down for a period after inversion. He also considers that the righting moment between 100 and 130 degrees is important in the yachts resistance to capsize.
Most of these factors relate to meeting very severe weather at sea, so that any boat which claims a classification of A should have taken these factors into account.
The trouble is that they conflict with the the floating caravan approach (more beam) in less length, and cost (heavier boats cost more to build).
Using these factors I looked back over a few recent boat tests. These tend to show there are the heavier cruising boats, such as the Najad, Halberg Rassy, Malo etc and the lighter boats that tend to be for more coastal work, since they are lighter and less heavily constructed. On this basis
A comparison of the Dehler 36 with the Legend shows, (Dehler figures in brackets)
Legend 10.8m(11.0), Beam 3.6m(3.5), Draught 1.9m(2.0), Displacement 6305kg(6000), Ballast 2297kg(2200), Sail Area 66.9sqm(71). It would therefore appear that the Legend is not built primarily as a deep water cruiser but is in the same category as the Dehler
Adlard Coles makes the point that stability is not everything, it is only one factor that will increase the resistance to knock down. He also says that although a heavier boat is more likely to be able to withstand a breaking sea she needs to be stronger in order to stand up to the heavier loads that this will impose. He then states:
"THE SKILL AND COMMON SENSE OF THE CREW AND THE TACTICS THEY EMPLOY MAKE THE GREATEST CONTRIBUTION TO CAPSIZE AVOIDANCE"
The heavy weather article makes some interesting points, for example that an area of shallow water in a deep area can create problems. This seemed to be the case in the '78 Fastnet, when most of the trouble occured in the vicinity of the Labadie Bank, where the water shoals from aroung 120 metres to about 60. It also makes the point of low pressure systems being trapped against high pressure systems, and the affect of currents against winds. These are clearly illustrated in the 'Fatal Storm'. The 'Fatal Storm' also illustrates that you need to make ground away from the storm centre and that running across the sea is the worst thing you can do, the sea must either be on the quarter or on the bow.
A further factor that needs to be considered is the strength of the crew and their resistance to bad weather. How long will your crew keep going if it is rough.
When I started to sail, almost 50 years ago, I was taught that you had to plan within the capability of the crew. Thus when my wife and I are sailing together we plan on 12 hours maximum, daylight only and weather forecast of no more than Force 5. This means that we are rarely out after midnight and have yet to be caught by more than a Force 8. We also have a boat that will look after us.
I would not wish to prevent anyone from sailing but when I see stories of a Sadler 32 with a husband, wife and two small children coming through the Needles channel in bad weather, or I remember the passage skipper who was charged with manslaughter of a crew member who drowned when a boat, said by the coroner to be unfit for the purpose, sank in the Bay of Biscay I wonder if this is still remembered.
I would therefore recommend that you define what you want a boat to do, and what skill levels you have available to do it before you start looking at boats. Then get the best for your purpose. And read all you can on other people experiences, it will be too late when the gale starts. When you do get to sea make sure you have thought through all the bad weather what ifs, where will you run to, what happens if you cannot get there and so on. And last of all take action early
I hope this is of interest to some and apologies to all who think I am teaching granny to suck eggs.
Chris
Chris Stannard
