Performance Anxiety

[Jim Cate]

Originally Posted by dannc

Is the boat a monohull? If so, I think every formula I have seen to calculate the speed of a boat depends on the water line length of the boat. Some use the boat displacement or wetted area as well but I think they all used LWL at some level.

A boat with a 40 foot water line length has a hull speed of 8.5 knots. 1.34 X sqrt( water line length)

To go an extra 1/2 knot, a 40 footer would have grow about 6 feet.

For a monohull, I don't think it is going to matter how much weight can be removed from an existing design/boat, hull speed and the ability to power over hull speed is going to be the limiting factor.

Later,
Dan

Dan, the typical "hull speed" calculation addresses the max speed that the boat can reach whilst in full displacement mode. Most modern monohulls will easily reach higher speeds downwind, especially surfing on the seas. For instance, our boat, with a 44 foot LWL frequently reaches speeds of 12 to 14 knots surfing, and has several times exceeded 15 knots. These are, of course, not sustained speeds, but if one can catch every wave, or a big fraction of them, one can materially improve over hull speed. The ease with which a given hull begins to surf is definitely related to weight, so Delancy's efforts to reduce weight may indeed improve his passage times... a little!

Further, in conditions where one can not reach hull speed (which describes a lot of sea time in my experience) again weight does influence speed. Quantifying the gains he might experience is not so easy for the casual punter, but to deny that they are there is not correct.

Finally, keeping one's boat light just makes it more responsive, and this, to me, makes it more fun to sail... even if it doesn't materially reduce passage times. So, while I might not remove a bulkhead to save weight, I can understand and even applaud Delancy's efforts.

Cheers,

Jim

[ontherocks83]

It seems every sport runs into this. When I was serious into backpacking and guiding there was a huge "Go Lite" movement (probably still is) for carrying the bare essentials and having the lightest gear available. People would go backpacking for days or weeks with next to nothing making the "least amount of impact" on the environment and carrying as little as possible.

These were also the people that when they got into trouble or hurt had no gear to be able to help or take care of themselves in an emergency and would rely solely on others to get them out of a jam. It used to drive me crazy.

There's a simple methodology in all of these situations, carry the equipment you need, don't carry the equipment you don't need.

[boom23]

It depends on how you use your boat. I do not have, or want, a race boat. I want a safe and comfortable boat. I've read somewhere that most cruisers spend over 95% of their time at anchor/dock. I want to make sure that my boat is comfortable for that 95% of the time so that my wife will enjoy the experience. If she does not, there will, probably, be no boat...

For my speed thirst, I have a smaller sailboat and other hobbies. I've done motorcycle and car racing, airplane flying, mountain biking, etc. I enjoy being on the edge.

For me, boating is for relaxation.

That's my 2 cents...

[goboatingnow]

Originally Posted by dannc

Is the boat a monohull? If so, I think every formula I have seen to calculate the speed of a boat depends on the water line length of the boat. Some use the boat displacement or wetted area as well but I think they all used LWL at some level.

A boat with a 40 foot water line length has a hull speed of 8.5 knots. 1.34 X sqrt( water line length)

To go an extra 1/2 knot, a 40 footer would have grow about 6 feet.

For a monohull, I don't think it is going to matter how much weight can be removed from an existing design/boat, hull speed and the ability to power over hull speed is going to be the limiting factor.

Later,
Dan

Not quite, it has to do with the wind to reach hull speed. Some heavy long keelers need a near gale to get going

Dave


Sent from my iPad using Tapatalk

[osirissail]

I suspect we are getting into basic definitions of what a "cruiser" is versus a "sailor." In my mind, a sailor is thinking and enjoying the movement and performance of his sailboat while a "cruiser" is merely interested in getting to the next wonderful location/harbor in a reasonably efficient and economical process.
Of course there are lots of folks who are mixture of "sailor" and "cruiser" but primarily the difference lies in sailing for the voyage or sailing for the destination.
All the weight savings ideas suggest a "sailor" attitude and sacrificing comfort and ease of passage making is secondary. For the "cruiser" the "extra poundage" is directly related to comfort and making the boat a "home." If we need more speed we get bigger or better sails. . .

[sailorboy1]

Originally Posted by Delancey

With an extra half knot of boat speed, a boat that is otherwise traveling at six knots can complete a 2,000 mile leg a day sooner. Am I the only one who sees value in this?

How much weight do you figure you will need to get the 1/2 knot average increase? Do you really think that there is really much difference between a 13.9 day trip and a 15.2 day trip that outweighs other factors on the boat. Would you only take 13.9 days of water?

[colemj]

Michele often thinks that our boat would benefit greatly through reducing its weight by 160lbs.

But she never mentions speed as a reason…

Mark

[robert sailor]

Well all kidding aside a 1/2 knot is a lot of speed to gain no matter how you do it. That's 12 miles a day on passages and I know few people that would not go to some effort if they thought they could gain a 1/2 knot. Feathering/folding props can do it in lighter air and many cruisers will spend the 3 grand but other than a clean bottom and decent sails there isn't much that you can do to get this amount of speed. Yes you can take out some weight but if its a medium displacement yacht your going to have to damn near empty it to gain a 1/2 knot.

[letsgetsailing3]

A half a knot speed increase would be nice, but you'd have to redesign the boat, not simply lose a few pounds in order to accomplish this.

For cruisers, performance is mostly about bragging rights. It's great fun to pass another boat, but if we're honest about it, you could also leave a half an hour earlier and achieve the same practical effect in terms of arrival times.

If you were in a hurry, you'd have taken a plane.

[JPA Cate]

Some people simply prefer responsive good sailing boats; others do not care, and some don't even care to learn reasonable sail trim. Some people are string pullers, and others flat out don't care. It's life.

The guy who brags about still using 20 yr. old sails, either cannot afford to change or truly does not care about sail shape.

Ann

[Delancey]

Originally Posted by Ann T. Cate

Some people simply prefer responsive good sailing boats; others do not care, and some don't even care to learn reasonable sail trim. Some people are string pullers, and others flat out don't care. It's life.

The guy who brags about still using 20 yr. old sails, either cannot afford to change or truly does not care about sail shape.

Ann

Ann T. Cate,

Just so that you know, I always pay attention when you have something to say as I oftentimes find your ability to render complex equations uncanny.

In this case I think you have it down cold.

That extra half a knot of boat speed I referred to is the product of a mindset. Some people have that mindset, some don't. Really, what more is there to say?

Cheers,
Del

[Andrew Troup]

Interesting range of views.

A good mate of mine built (with his own hands, except for a few helping hands, including mine) an astonishingly fine 40' cruiser racer, but in most parts of the world it would be a racer-cruiser (except perhaps for having convenience items like a Leisurefurl boom)

I've sailed with him on some ambitious itineraries.
One one occasion we set off around one of the world's more challenging Capes in a forecast I would be embarassed (and disbelieved) if I were to repeat it here.

It was in fact the best weather window we were likely to get (and I think the passage of time bore this out) before things took a turn for the worse, with winter only a couple of months away.

I mention this only because I am reminded, and want to emphasise for the sake of this discussion, what a wholesome boat it is -- we had a fantastic sail -- as we always seem to, on that vessel -- in conditions exactly per forecast.

And yet, the ruling principle my friend followed, without compromising strength, was to spare no effort (and little expense) to save weight. The saloon table is a work of consummate beauty, able to be set level at any angle of heel, but under the veneers is some high-tech core material more usually found in the hulls of race yachts.

The rudderstock is a particular work of art; he visited some of the exceptional super-yacht builders in this part of the world and they were generous with their time and advice (I think he may even have worked unpaid for at least one, but I may have that mixed up with another enterprising mate). He learned enough about carbon fibre composite to make a truly awesome job, including stainless steel journals moulded integrally, and then machined by him to a precision fit for the state-of-the-art self aligning spherical roller bearing units. This is a deep spade rudder, massively strongly built (way in excess of anything a skeg could realistically provide any rudder, and I say that as a design engineer)

Then he went on to build a carbon fibre quadrant. He already had the teak and carbon fibre steering wheel: He'd made that first of all, just for kicks, then decided he might as well have a yacht for it to go on. There has never been a failure of any of these lightweight items, a decade and a half later.

He's now in his mid 70s, and over the years we've many many times almost but not quite hit the magic 200 nautical miles in a 24 hour day. (On a boat like this, such a day's run requires regular bursts of speed up to 15 knots, so theoretical hull speed is not an applicable consideration)

On a trip last year back from the Pacific, with his young family, they were hove-to off NZ's East Cape when he said to his son "What are we doing this for? The wind shows no sign of dropping, but it is, now, from the right direction" so they made sail, straight-lined it for home, incidentally cracking the 200mpd on the way. He was over the moon.

I'm not as competitive as he is, but it is a sheer delight to sail with him and on his boat, regardless of itinerary, because it is such a thoroughbred and SO free of handling vices.

It sports a ballast bulb on a deep draft, minimum drag keel, powerful buttocks (although well short of extreme), buggerall volume in the bilge. The projecting tail on the bulb is admittedly a pain if the chain gets round it when anchored in williwaw conditions - that's possibly the one aspect which is sub-optimal for cruising - but it has only actually happened once. (perhaps also the minimal capacity for bilgewater rates a 'downside' mention - unavoidable with this hull form, except in an aluminium boat where a sump can be built in the top element of the fin keel)

If you believed what you read on the www a boat like this should not be able to heave to, be horrible to steer in storm force winds, jerky motion, etc etc.

Bollocks. Running in the biggest seas it has ever seen, with just the storm staysail, I recall using my thigh to immobilise the wheel rim and warming my hands in my bib pants for minutes at a time.

And I say "Bollocks" based not just on this example: I've been fortunate to sail on full keel boats to nasty corners of the subAntarctic, and radical ocean racers in the Southern Ocean, and most things between, and I just do not understand where people are coming from when they rhapsodise about skegs, slack bilges, etc etc.

My observations suggest that there are sweet boats and there are pigs.

But there's no pattern linking that to specific design types, at least not that I have ever been able to detect.

And the sweet boats are not always fast, but they are almost always good performers for their type.
To me, a boat has to be responsive enough that you can work it to windward nicely without having to look, and if it passes that test in a variety of conditions, more often than not it will be OK handling-wise under most circumstances.

I'm probably off-topic and certainly over any reasonable word limit, but what I'm trying to substantiate is my reasons for seeing no yawning gulf between performance and fitness for voyaging.

[Andrew Troup]

Let me clarify that making an offshore boat unusually light is not something I would ever suggest every owner should pursue with zeal on key, mission critical items, unless they have commensurate skill and knowledge, or advice from a trained professional, working for hire.

One avenue which I think is well worth pursuing, though, is not the quantum of weight but the LOCATION.

Example: I'm a fan of plenty of generously sized chain.

And so I'm a fan of a chainlocker back by the mast. If the chain can be pulled out inspection ports in the bottom of the locker and spread in the bilge for offshore passages (under bolted-down sole panels!) after duly cleaning, naturally... you can get all that weight low enough to justify a substantial reduction in the formal ballast for a cruising boat - and in a grounding, the chain will naturally be going into the water, floating you off earlier.

win win win.

[deluxe68]

Originally Posted by Andrew Troup

Interesting range of views.

A good mate of mine built (with his own hands, except for a few helping hands, including mine) an astonishingly fine 40' cruiser racer, but in most parts of the world it would be a racer-cruiser (except perhaps for having convenience items like a Leisurefurl boom)

I've sailed with him on some ambitious itineraries.
One one occasion we set off around one of the world's more challenging Capes in a forecast I would be embarassed (and disbelieved) if I were to repeat it here.

It was in fact the best weather window we were likely to get (and I think the passage of time bore this out) before things took a turn for the worse, with winter only a couple of months away.

I mention this only because I am reminded, and want to emphasise for the sake of this discussion, what a wholesome boat it is -- we had a fantastic sail -- as we always seem to, on that vessel -- in conditions exactly per forecast.

And yet, the ruling principle my friend followed, without compromising strength, was to spare no effort (and little expense) to save weight. The saloon table is a work of consummate beauty, able to be set level at any angle of heel, but under the veneers is some high-tech core material more usually found in the hulls of race yachts.

The rudderstock is a particular work of art; he visited some of the exceptional super-yacht builders in this part of the world and they were generous with their time and advice (I think he may even have worked unpaid for at least one, but I may have that mixed up with another enterprising mate). He learned enough about carbon fibre composite to make a truly awesome job, including stainless steel journals moulded integrally, and then machined by him to a precision fit for the state-of-the-art self aligning spherical roller bearing units. This is a deep spade rudder, massively strongly built (way in excess of anything a skeg could realistically provide any rudder, and I say that as a design engineer)

Then he went on to build a carbon fibre quadrant. He already had the teak and carbon fibre steering wheel: He'd made that first of all, just for kicks, then decided he might as well have a yacht for it to go on. There has never been a failure of any of these lightweight items, a decade and a half later.

He's now in his mid 70s, and over the years we've many many times almost but not quite hit the magic 200 nautical miles in a 24 hour day. (On a boat like this, such a day's run requires regular bursts of speed up to 15 knots, so theoretical hull speed is not an applicable consideration)

On a trip last year back from the Pacific, with his young family, they were hove-to off NZ's East Cape when he said to his son "What are we doing this for? The wind shows no sign of dropping, but it is, now, from the right direction" so they made sail, straight-lined it for home, incidentally cracking the 200mpd on the way. He was over the moon.

I'm not as competitive as he is, but it is a sheer delight to sail with him and on his boat, regardless of itinerary, because it is such a thoroughbred and SO free of handling vices.

It sports a ballast bulb on a deep draft, minimum drag keel, powerful buttocks (although well short of extreme), buggerall volume in the bilge. The projecting tail on the bulb is admittedly a pain if the chain gets round it when anchored in williwaw conditions - that's possibly the one aspect which is sub-optimal for cruising - but it has only actually happened once. (perhaps also the minimal capacity for bilgewater rates a 'downside' mention - unavoidable with this hull form, except in an aluminium boat where a sump can be built in the top element of the fin keel)

If you believed what you read on the www a boat like this should not be able to heave to, be horrible to steer in storm force winds, jerky motion, etc etc.

Bollocks. Running in the biggest seas it has ever seen, with just the storm staysail, I recall using my thigh to immobilise the wheel rim and warming my hands in my bib pants for minutes at a time.

And I say "Bollocks" based not just on this example: I've been fortunate to sail on full keel boats to nasty corners of the subAntarctic, and radical ocean racers in the Southern Ocean, and most things between, and I just do not understand where people are coming from when they rhapsodise about skegs, slack bilges, etc etc.

My observations suggest that there are sweet boats and there are pigs.

But there's no pattern linking that to specific design types, at least not that I have ever been able to detect.

And the sweet boats are not always fast, but they are almost always good performers for their type.
To me, a boat has to be responsive enough that you can work it to windward nicely without having to look, and if it passes that test in a variety of conditions, more often than not it will be OK handling-wise under most circumstances.

I'm probably off-topic and certainly over any reasonable word limit, but what I'm trying to substantiate is my reasons for seeing no yawning gulf between performance and fitness for voyaging.

Perfectly stated. That is exactly what I am looking for in our next boat for cruising.

[atoll]

Originally Posted by Delancey

To me, performance is important. If for nothing else, I consider it a safety feature and to this end I make every possible effort to maximize my boat's potential.

I have made a number of small changes as well as some more noticeable ones to my mid-eighties production boat including having removed several partial bulkheads, most of the interior doors, and any superfluous cabinetry.

Elsewhere I have done things like removing the steering wheel and replacing it with a tiller, removed a mast pulpit I felt was a tripping hazard, or traded the cabin top main sheet traveler with a cockpit arrangement.

I do these things to reduce weigh and increase ease of handling because even though I am a cruiser, I think a couple pounds here and there can make a difference and because things like being able to instantly ease the main in a puff while driving the boat single handed is more important to me than having an uncluttered cockpit.

I can't say I have seen this topic directly addressed and sometimes I wonder if I am the only one who thinks this way....

my friend alex up graded his boat in the way you suggested for his last circumnavigation..........even got a smaller girlfriend.......

alex klaar on Vimeo