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Old 27-08-2009, 11:53   #76
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Originally Posted by barnakiel View Post
And for those who like the Collin Archer version of the picture (which I love!) I can send you guys to contact NZ coastguard - 17 boats lost in the NZ / the Islands passage over last 15 years - at least 12 of which 'long keel heavy displacement'.

True said the average speed of the hurricane does not count - the actual case does - yet the average does not have to be gambled - it can be retrieved from NHC NOAA data. But without weather services support from NHC or any other reliable source the weather dodging can hardly be done (even in a 60ft skiff). Still a lot can be done to move the boat about - but the boat has to be a movable one, not a heavy displacement, long keel clunker (which is the most beautiful boat to have, in the harbour).

b.
These numbers mean nothing unless you know the percentage of "long keel" vs modern "fin keel" sailboats that attempted the passage in those same weather conditions with the same number of crew, comparably experienced.

And as others have noted, hull speed is hull speed regardless of keel configuration, unless you are talking about multi-hulls, exotic racing boats or power boats.
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Old 27-08-2009, 12:29   #77
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Originally Posted by S&S View Post
...
Heavy, withen reason, doesn't necessarily equate with "slow" and a full keel doesn't necessarily equate with unmanoeverable "clunker".But a flat bottom and a skinny fin keel does make things more interesting in heavy weather- and not in a good way.
Since you are using 'within reason' to classify heavy boats, why not use the same 'within reason' for lighter boats, instead of throwing all into one, unfavorable, category? I have owned two boats that I have cruised and used offshore. Both about the same length. Can you tell me which one is the heavy one and which is the light one - don't peak at the answer below?
1. Alberg 35
2. J/37

They are about the same displacement. And as far comfort in tough conditions, while I have never been in survival conditions in either boat, I can tell you that in really rough conditions both are uncomfortable and the J is much easier to manage.

Paul L
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Old 27-08-2009, 13:13   #78
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Originally Posted by hellosailor
Take a nice plumb bow like a J/24 out into a two foot chop, and all you do is pound-stop-start-pound-repeat as that plumbbow cannot ride up over any kind of choppy water, and instead acts as a very effective brake.

Uhh.... if you really believe this you need to look at some videos of the round the world racers in the southern ocean.... what acts as a brake is a wide bow with too much area as it hits the wave. Of course the plumb bow is a wet ride !
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Old 27-08-2009, 13:36   #79
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Originally Posted by Paul L View Post
Since you are using 'within reason' to classify heavy boats, why not use the same 'within reason' for lighter boats, instead of throwing all into one, unfavorable, category? I have owned two boats that I have cruised and used offshore. Both about the same length. Can you tell me which one is the heavy one and which is the light one - don't peak at the answer below?
1. Alberg 35
2. J/37

They are about the same displacement. And as far comfort in tough conditions, while I have never been in survival conditions in either boat, I can tell you that in really rough conditions both are uncomfortable and the J is much easier to manage.

Paul L
Sure, displacement and underbody configuration are just two of the variables as is sea state. If you're on long rollers going downwind you won't notice that a flat underbody will pound as you would in a short sea with overfalls. In the conditions I've experienced in both types of boats, I'd have a preference for easy bilges. The proof is in the pudding and I've not been on a J 37 in what I'd call "really rough"conditions so if it suits you better, great.
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Old 27-08-2009, 13:38   #80
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Originally Posted by hellosailor
Take a nice plumb bow like a J/24 out into a two foot chop, and all you do is pound-stop-start-pound-repeat as that plumbbow cannot ride up over any kind of choppy water, and instead acts as a very effective brake.

Uhh.... if you really believe this you need to look at some videos of the round the world racers in the southern ocean.... what acts as a brake is a wide bow with too much area as it hits the wave. Of course the plumb bow is a wet ride !
Umm. it works somewhat differently when you're normal mode is surfing at 20 knots.
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Old 27-08-2009, 15:13   #81
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surfing at 20 knots.
Ah, thank you for giving me the chance to make this remark:

Sailboats that are surfing do this down the face of a wave. They accelerate to well over hull speed during the surfing, but when the wave passes, they fall back to hull speed. They need the energy from the wave, in addition to the energy from the wind to sail at that speed.

Racers can surf too, but they take it a step further: they can sustain planing without the need for a wave to power it. The wind alone provides enough power for them to plane. This is very different from surfing, which every sailboat can do.

The most asked question we get about Jedi is how fast she can sail. The answer is 26 knots. When we say that, we always get to hear the story about how they did 10-18 knots once etc. They are talking about surfing, we are talking about planing. As far as I know, the Sundeer 64's are about the only production cruisers that can sustain planing. We might need the help from a wave to start planing (when there's less than 25 kts wind), but we keep planing after the wave is gone. The reason a Sundeer 64 can do this, is that the boat is 64' long, has the under water lines for it, and is very light displacement. The light displacement is because the interior is only 39' between the two watertight bulkheads, plus the balsa cored hull and deck.

The racers plane all the way continuously. Open 60's have the same hull speed we have: 11-12 kts and I don't even want to guess their 24hr average but I'm sure it's well over 300 nm (we can already do better than 300nm). I wouldn't be surprised when they do more than 400 nm. They need to plane continuously to make that average speed.

So, they plane at 20 knots, not surf at 20 knots ;-)

Now, about that "light displacement boats bounce around" theory. It's flawed. It is the total, absolute weight of the boat that makes it a smooth ride or not. So, a very light displacement boat that weighs 50,000 lbs, behaves nice at sea, even nicer than a shorter boat with the same weight.

cheers,
Nick.
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Old 27-08-2009, 16:07   #82
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Well put Nick. Whatever boat gets you there works, but I've come full circle over the years, "light is right!". Light designs do tend to be a little more jerky, but I think that's more due to their modern shapes than what they weigh. My Passport 47 was a beautiful, long waterline boat but heavy. In steep chop and 30 knots ont he Chesapeake and just south of Hattaras I was passed by boats that were smaller, lighter and had pretty plumb bows!
As far as the original posting: What is Bluewater? Well the young man (16 year old?) that just finished sailing around the world was in an old 36 ft Islander production boat. As I remember, the original Dove was a production boat too... and Joshua Slocomb's Spray was pretty much a salvage job wasnt it?
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Old 27-08-2009, 16:17   #83
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Originally Posted by S&S View Post
Sure, displacement and underbody configuration are just two of the variables as is sea state. If you're on long rollers going downwind you won't notice that a flat underbody will pound as you would in a short sea with overfalls. In the conditions I've experienced in both types of boats, I'd have a preference for easy bilges. The proof is in the pudding and I've not been on a J 37 in what I'd call "really rough"conditions so if it suits you better, great.
As I noted, in both cases it is uncomfortable. There's no such thing as small boats in rough conditions being comfortable. But those long over hangs of the very good looking, in my opinion, Alberg 35, lead to some nasty hobby-horsing in rough conditions. The need for the boat to get into a large heel before it finds any stability also make for a most uncomfortable ride for me. The boat was designed to old racing rules, not for comfort of ride. Certainly hard on the weather in rough conditions the J is likely to pound. But I can crack off 5 or 10 degs and go for a more comfortable ride and still be sailing higher than most. To each his own.

Paul L
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Old 27-08-2009, 16:25   #84
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So, they plane at 20 knots, not surf at 20 knots ;-)
Yep- plane.

In any event,the boat is running faster than hull speed which is the normal limit for the "hole in the water" types. The potential disadvantages for hull forms that are capable of sustained planing were illustrated in the pic on the last page. Don't see how one could get around that.
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Old 27-08-2009, 17:13   #85
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The potential disadvantages for hull forms that are capable of sustained planing were illustrated in the pic on the last page. Don't see how one could get around that.
Well, we don't need to get around that, but because this is a nice discussion, I'll try anyway ;-)

The photo is showing what? A racer that's upside down, inverted, 180 degree heeling. For some reason, it's either bow or stern into the waves in a very calm sea. Most boats, incl. all (but one, probably) cruisers, need the help of a wave on the beam to go right side up again. This racer might right itself too, when a wave on the beam gives a hand.

The racer. Look at the shape of the hull. This is not a yacht, it is a very big dinghy. The shape is much like that of a 470 or Flying Dutchman. It is a pure speed machine, not at all designed to provide comfort in any conditions, let alone rough weather.

Now image yourself the shape of the hull of a planing powerboat. It's much different but still, it can plane too. So, this illustrates that there are more ways to design a planing hull. The powerboat needs to carry much more weight than the racer, and that leads to a different hull.

Now look at the first photo I attached: a table planes too, even though the shape is very different again.

Architects are able to design hulls that are a compromise. For a racer, two things are important: speed, plus just enough seaworthiness to make it to the finish line.
For a cruiser, speed normally comes much lower on the list, and things like interior volume and number of berths are higher up.

But sometimes, a designer wakes up and draws a shape that is very safe but fast and comfortable too. It will probably cost more to build so the big series production yards won't buy the design. Steve Dashew didn't care and he build them himself instead. The second photo gives a good view of our hull shape. You can see that the bottom is much flatter than most other cruisers, especially the aft section (for planing) but nothing like that of a racer as shown earlier in the thread.

Each and every design must be looked at separately, you can't just say "all light displacement this" or "all full keelers that", because there are huge differences within those groups.

So, did I get around? ;-)

ciao!
Nick.
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Old 27-08-2009, 17:34   #86
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Nick,
In addition the pic referenced above is an older design boat. Due to issues like this most (all) of the box rules (like Open 40 Open 60) for open ocean racing now have strict stabilty and self-righting requirements. And these are not some pie in the sky requirement that gets faked by the numbers, they actually flip the boat and see how it recovers.


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Old 27-08-2009, 19:36   #87
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Although the design of a blue water boat may be rocket science, it seems to me that from the mariner's perspective it's mostly common sense. When sailing offshore, the wind will sometimes blow very hard and the waves will get big-- for days on end. You will be far from land with no sheltered anchorage in which to seek refuge.

So, you need a boat that is up to the task. It has to be sturdy (hull and rigging). It should have redundant systems (e.g pumps) and all of the accessories needed for storm conditions (parachutes, drogues, etc.) with the ability to heave to if necessary. It should be able to recover from a knockdown.

So if a boat, whatever it's configuration, can do these things, then it's a blue water boat.
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Old 27-08-2009, 20:16   #88
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I would not include heaving to as a must have. But it is indeed a nice to have. Found out the hard way when knocked down. So as an ultimate tactics from then on I say - beat or run, but never park.

May sound a bit philosophical and sure is - but what we do with the boat, how we manage bad weather, extends on and influences our mindset.

So beat or run, but never park.

b.
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Old 27-08-2009, 20:54   #89
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Nick,
In addition the pic referenced above is an older design boat. Due to issues like this most (all) of the box rules (like Open 40 Open 60) for open ocean racing now have strict stability and self-righting requirements. And these are not some pie in the sky requirement that gets faked by the numbers, they actually flip the boat and see how it recovers.
Actually not. That picture is from the 2008-2009 Vendee Globe. The boat was built in 2004.

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Originally Posted by s/v Jedi View Post
The photo is showing what? A racer that's upside down, inverted, 180 degree heeling. For some reason, it's either bow or stern into the waves in a very calm sea. Most boats, incl. all (but one, probably) cruisers, need the help of a wave on the beam to go right side up again. This racer might right itself too, when a wave on the beam gives a hand.
This boat will never right itself. The reason it is inverted in the first place is because the keel bulb is gone. It hit an object and the bulb at the end of the keel sheared off. BTW - this picture was taken 200 miles due south of cape horn.

All that being said, the fate of this boat is mostly irrelevant to this thread. The only lesson to be learned from it's fate is that a long, thin keel with most of the weight on a bulb at the bottom is VERY vulnerable and therefore a very bad idea for a cruising boat.
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Old 27-08-2009, 22:27   #90
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This boat will never right itself. The reason it is inverted in the first place is because the keel bulb is gone.
I knew it was a trap I was getting in. So, I change my story to: "assuming the keel bulb would still be in place, it might right itself... etc."

Quote:
The only lesson to be learned from it's fate is that a long, thin keel with most of the weight on a bulb at the bottom is VERY vulnerable and therefore a very bad idea for a cruising boat.
Oh I admit the keel shape is pretty radical and I have never seen it under a cruiser so the designers don't need the lesson. I do agree with the keel not being good for a cruiser, but for different reasons: you can improve the bulb-keel attachment strength easily; the problem is that a bulb like that makes a pretty good hook when you run aground (just like wing keels which are used for cruisers), plus it's a bit much draft so impractical for a cruiser.

cheers,
Nick.
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