Good Sailing Performance?

[onesea]

Rather than out and out speed, consider the boats' handling; no point going around supersonic with your hair on fire, if you arrive knackered after fighting the helm.

That depends upon how you like your sailing! You can always tuck a reef in.

Another thought for you with soft mud and descriptions you describe I guess you have large tidal range but its the time taken for the keel to get out of the mud. If sailing round draft restrictions the ability to sneak in and out a bit earlier opens your sailing window wider.

From what you would say I would think maybe toward a lift keel?
http://www.parkerseal.org.uk/forsale/Kerygma.aspx
or Similar often good in light winds and respected sea boats.
http://www.ancasta.com/boats-for-sale/sadler-25-28387/
A little bit more steady but remember your draft restrictions.

Just watch for old engines some run for ever others cost you money...

What ever you buy will be a compromise, even if you had a huge budget.

 

[lw395]

Sad to say, but the only way you are going to see passages averaging 6kt on a regular basis with only 26' of boat will be in a multihull or a foiler!

if you want to step down to a monohull that small you will have to join those of us slouching along at more like a 4 kt average.

Not entirely true, I've done some 6knot passages in a 22 ft boat, over the ground by not fighting the tide.
Equally, a 40ft boat can struggle to make good 4knots on a beat.
Sailing performance will also vary from boat to boat within the same design.
Good sails, gear that works and a clean fair bottom make a huge difference.

I think the RTIR is a useful guide, there is a lot of data for a lot of boats over the years.
But look at the spread for say Co32s or even the Sunsail boats, which are very well matched....

 

[Fantasie 19]

...The Fulmar was sold due to cost versus the amount of time spent aboard especially since the wife decided she has persevered enough and boating really isn’t for her. So I’m looking for something that will tie up less money to a pontoon that I can use mainly for single handed day sailing plus occasional longer south coast passage/cross channel trips....

Are you going to be able to justify the time spent away frm the current Mrs Amp1ng for cross channel and south coast cruising?? If it was me I would gear my search towards the day sailing... you can always charter if you want to go further afield... plenty of smaller "exciting" boats about, and you save money.... just a thought...

One other thought... as the previous and other posters mentioned - for SOG tide is king - yesterday we were out in a 30 foot AWB, averaged 6 knots all day - but 2.5 to 3.5 of that was tide assisted...

 

[Seajet]

That depends upon how you like your sailing! You can always tuck a reef in.

Another thought for you with soft mud and descriptions you describe I guess you have large tidal range but its the time taken for the keel to get out of the mud. If sailing round draft restrictions the ability to sneak in and out a bit earlier opens your sailing window wider.

From what you would say I would think maybe toward a lift keel?
http://www.parkerseal.org.uk/forsale/Kerygma.aspx
or Similar often good in light winds and respected sea boats.
http://www.ancasta.com/boats-for-sale/sadler-25-28387/
A little bit more steady but remember your draft restrictions.

Just watch for old engines some run for ever others cost you money...

What ever you buy will be a compromise, even if you had a huge budget.

Onesea,

I was referring to design as in being pleasant to helm - not sail trim, responsive but not twitchy; rudder authority plays a large part in this, for the sake of handling a spade type not blanketted and stalled by a deep skeg ( though rudder protection is a different issue ).

The tide range is quite moderate in the Solent, say 16'; as for lift keels, through sheer cowardice I never raise the keel when sailing ( though she is self righting with it up ) - the major plus is not ditch crawling as some people think - not much difference between 2' and 4'6" - but allowing the use of cheaper and pleasanter, sheltered shallow moorings close to the shore - I tried various deep water moorings with another boat and they were all a PITA !

As for speed when passage making, I have always thought the old ' 1.4 X square root of the wetted length ' a bit suspect, my 22' boat is no boy racer machine but she has averaged 7 knots across the Channel, however that was an ideal beam reach; for nav' planning I work on 5 knots but am usually pleasantly surprised.

 

[Twister_Ken]

Rather than out and out speed, consider the boats' handling; no point going around supersonic with your hair on fire, if you arrive knackered after fighting the helm.

As Twister Ken mentions you probably don't need a boat much longer than 20'; how about A Europa or other Oliver Lee designs ?!

Or if determined on a bigger boat, how about an Impala.

Of course, an Anderson 22 would do rather nicely!

 

[lpdsn]

Rather than out and out speed, consider the boats' handling; no point going around supersonic with your hair on fire, if you arrive knackered after fighting the helm.

Drifting well away from the OP's question I know, but... do you mind if I ask if you've ever helmed a boat built for out and out speed? I'm not talking about an AWB variant with slightly more sail area than the cruising version and a cruiser-racer label, but a real purpose-built racer.

You don't have to fight the helm as you seem to believe, in fact you have to take care to only make tiny adjustments to avoid oversteering. Mental concentration is extremely important but that's not the same as arriving knackered after struggling to keep the boat on course.

 

[Twister_Ken]

Drifting well away from the OP's question I know, but... do you mind if I ask if you've ever helmed a boat built for out and out speed? I'm not talking about an AWB variant with slightly more sail area than the cruising version and a cruiser-racer label, but a real purpose-built racer.

You don't have to fight the helm as you seem to believe, in fact you have to take care to only make tiny adjustments to avoid oversteering. Mental concentration is extremely important but that's not the same as arriving knackered after struggling to keep the boat on course.

1720 and a J80. As you say treat the tiller very gently - the thought of inducing a broach at 17kts is somewhat scary.

 

[Seajet]

Drifting well away from the OP's question I know, but... do you mind if I ask if you've ever helmed a boat built for out and out speed? I'm not talking about an AWB variant with slightly more sail area than the cruising version and a cruiser-racer label, but a real purpose-built racer.

You don't have to fight the helm as you seem to believe, in fact you have to take care to only make tiny adjustments to avoid oversteering. Mental concentration is extremely important but that's not the same as arriving knackered after struggling to keep the boat on course.

Well if you count Carter 30, Dart 18, Scorpion, Fireball, Osprey, E-Boat, and a few others I've forgotten in 44 years, then yes

I don't ' believe one has to fight the helm ' in well designed and trimmed boats; one Anderson 22 owner commented he had racing sailors come along ' just for the feel on the tiller ' - a boat should talk to the helmsman and be responsive, but not give him or her a workout !

You are welcome to come along for a go when she's launched and set up; can't guarantee the weather though...

Andy

 

[onesea]

SeaJet,

When I was saying about lifting the keel you are telling me you wait for the tide to raise high enough to lower your keel before leaving the mooring? When I said sneaking in and out I mean in and out of berth in to the main channel. Even at 16' range you can wait an hour to gain an extra meter, its still a reduction in potential sailing Windows.

Most boats if pushed become more physical to sail, it might not fighting with the tiller it could be trimming the main more tweaking the controls etc. you can choose how to sail any boat.

Generally though heavier / long keel boats will be more comfortable forgiving and less physically demanding once the wind pipes up. Any extra effort to put is not be noticed as readily apparent as with a lighter fin keel design, where trimming sails constantly can make significant improvements in speed.

 

[Twister_Ken]

Generally though heavier / long keel boats will be more comfortable forgiving and less physically demanding once the wind pipes up. Any extra effort to put is not be noticed as readily apparent as with a lighter fin keel design, where trimming sails constantly can make significant improvements in speed.

Having raced Swans (older S&S ones) for many years I can't agree. They required constant trimming of big sail areas to squeeze competitive performance out of them. If you want exercise, try short tacking a big old boat in a breeze.

 

[Seajet]

Having raced Swans (older S&S ones) for many years I can't agree. They required constant trimming of big sail areas to squeeze competitive performance out of them. If you want exercise, try short tacking a big old boat in a breeze.

A good example being the Nicholson 43 with the ginormous headsail !

Even the IOR influenced Carter 30 was hard work changing headsails, and suffered the rudder stalling behind the full depth skeg, which is what I'm trying to say about handling - not sail trim, and not just rudder authority either, it takes a balanced hull and a rig to suit.

I've never sailed one, but by all acounts the Hunter 490 is a boat with wonderful handling, and yes I rate my boat on that score too, no boat is perfect but I've not found anything better in 36 years.

By good handling I mean just a touch of weather helm ' to steer against ', without loading up when pressed hard, and willing to do what the helmsman wants be it racing or manouvering in a marina.

As an example of what I rate as my favourite racing dinghy, the Osprey, she was seemingly responsive to just ones' thought of a course change, but never heavy on the helm or twitchy.

Compared to the trendy International 14 I crewed on, slightly faster but handled like a rocket powered tea trolley...

Onesea,

I am not ' asking you to believe I wait for the tide at the mooring to lower the keel ', sorry I should have been clearer; of course I sail or motor off with the keel up, sometimes leaving a furrow in the mud, but being a naturally cautious type I don't raise both sails in any fresh wind until I have the keel down; Bob Salmon sailed most of the way across the Atlantic with ' Anderson Affair's keel up, but I reckon if God and Oliver Lee ( same person ) designed a keel for me, I'll use it !

 

[TimBennet]

. . . and suffered the rudder stalling behind the full depth skeg,

Whatever happened to the rudder it didn't 'stall' as that is impossible with a full depth skeg.

However, I do agree there are good boats and bad boats and lightweight boats and heavyweight boats, and no simple correlation between them.

 

[Spirit of Glenans]

If you would consider a fairly broad fin keel, go for a UFO 27. It's the 'missing link' between the Twisters and the Oysters. I had one and sold it to buy a Dufour 30. I wish I hadn't

 

[Amulet]

Amulet is rather like a Contessa 26 - for passage planning in normal circumstances we reckon with 4 knots - that usually turns out a little pessimistic, but not much.

 

[Seajet]

Whatever happened to the rudder it didn't 'stall' as that is impossible with a full depth skeg.

However, I do agree there are good boats and bad boats and lightweight boats and heavyweight boats, and no simple correlation between them.

Tim,

why is it ' impossible to stall a rudder with a full depth skeg ' ?

I wish I'd known that on the several times I experienced rudder stall on the Carter 30 !

Unless one goes to town with things like vortex generators there's every chance of the skeg masking the flow over the rudder in tight turns or broaches, an anology would be the ' all moving horizontal tailplane ' developed on aircraft for the same reason.

 

[TimBennet]

why is it ' impossible to stall a rudder with a full depth skeg ' ?

The rudder is simply a trim tab on the back of the skeg. The foil is a combination of the skeg and rudder and it's impossible to have the angle of attack high enough to stall such a combination. It's well documented in the literature.

You can certainly oversteer with a skeg hung rudder putting it over far enough that it essentially acts as a brake and not a trim tab, but in such cases the pressure on the tiller arm is high.
In contrast when a spade rudder stalls, the loadings on the tiller arm tend towards zero, thereby encouraging beginners to apply more helm, rather than less helm to reattach the flow.

 

[KellysEye]

> but I like passages at 6knts through the water

If you want work out what boat you need for six knots this is the basic data on how to calculate it from water line length, displacement and sail area from detailed and extensive research on Beth and Evans Starzinger's site: http://www.bethandevans.com/pdf/200mile.pdf It's definitely worth reading it all but this is an extract.

Using a statistical technique called multiple regression to analyze a random sample of 140 monohulls ranging from heavy displacement traditional designs to ULDBs, we examined the effect various boat characteristics had on rated speed as calculated under IMS. We found that waterline length (LWL) and the sail area to displacement (SA/D) ratio explained more than 95% of the differences in speed between different boats, and thus were the key drivers of sailing performance across the fleet. We ended up with the following equation:
IMS rated speed in knots = 2.62 + 0.066*SA/D ratio + 0.051*LWL in feet
This equation says that anything that looks vaguely like a modern sailboat can manage to make good 2.62 knots on average no matter what its other characteristics might be. This is reasonable in light of the fact that ‘drift’ speed seems to be between 1 and 2 knots: Hugh Vilhen averaged just under a knot crossing the Atlantic in 5'4" Father’s Day, and Thor Heyerdahl and his crew of scientists floated from Peru to the Tuamotus at an average speed of just under 2 knots on the raft Kon-Tiki. Beyond that, IMS rated speed correlates to waterline length and the sail area to displacement ratio. An increase of five points in SA/D ratio, say from 15 to 20, will, on average, result in an increase of a third of a knot of boat speed (5*0.066=0.33) or 8 nautical miles per day; and an increase of five feet in waterline length will, on average, result in an increase of a quarter of a knot (5*.051=0.255) or 6 nautical miles per day, very close to what we found in analyzing the Bermuda Race and ARC data. Because it’s based on IMS data, which assumes a certain wind profile, boats will do better than this average on breezy, downwind passages and worse on light air or windward passages.

 

[Seajet]

Tim,

I'm afraid we will have to agree to differ; I certainly don't think of my rudder as a trim tab, which is traditionally used to correct balance, or as a servo to actuate the main rudder.

What literature do you refer to re skeg and rudder foils ?

I am used to sailing boats and usually steer with two fingers lightly on the tiller, not taking big handfuls.

It certainly is possible for a rudder behind a full depth skeg to stall, it's easy to picture when one thinks about it, and I have experienced it; for that matter it's possible to stall keels as well, with flow separation from high angles of attack, without even a skeg in front to mask the flow.

 

[Bobc]

Can I suggest that you take a look at a late Trapper 500/501, and perhaps a Moody 27 (although that might stretch the budget a bit).

http://yachts.apolloduck.co.uk/advert.phtml?id=340976

http://yachts.apolloduck.co.uk/feature.phtml?id=206926

http://yachts.apolloduck.co.uk/advert.phtml?id=331709



Both good all-rounders with good sailing ability and more internal room than a co26.

 

[Amulet]

I don't buy it I'm afraid. Unless I've misunderstood they did a simple linear regression. This is obviously inappropriate as the speed is zero bounded, and also displacement hull speed is known to be proportional to the square root of the waterline length - which is pretty good hint that you're not going to get away with pretending the relationship is linear. Having done a linear regression on non-linear data they end up with an intercept of 2.62, which is completely meaningless, but they make a half-assed attempt to explain it. In all, the passage you quote looks to me like complete statistical twaddle, and I'm surprised that it is published.

The maximum displacement hull speed of any hull in knots is roughly equal to the square root of the waterline length in feet times1.34 or thereabouts. (With the exceptions of very narrow or wave-piercing hulls, and planing hulls.) This means that a lwl of 20 feet can just be pushed at a MAXIMUM of six knots. (OK, if you apply an absurd amount of energy you might be able to make a non-planing hull plane, but something would probably break.) The hydrodynamics of why this is the case are well understood. I plan on 4 knots for my boat, which is about 20 feet on the waterline, and can be pushed to just over 6 knots. If you want to break this hull-speed barrier, get a multihull with waterline beam less than about a twelfth of lwl.

> but I like passages at 6knts through the water

If you want work out what boat you need for six knots this is the basic data on how to calculate it from water line length, displacement and sail area from detailed and extensive research on Beth and Evans Starzinger's site: http://www.bethandevans.com/pdf/200mile.pdf It's definitely worth reading it all but this is an extract.

Using a statistical technique called multiple regression to analyze a random sample of 140 monohulls ranging from heavy displacement traditional designs to ULDBs, we examined the effect various boat characteristics had on rated speed as calculated under IMS. We found that waterline length (LWL) and the sail area to displacement (SA/D) ratio explained more than 95% of the differences in speed between different boats, and thus were the key drivers of sailing performance across the fleet. We ended up with the following equation:
IMS rated speed in knots = 2.62 + 0.066*SA/D ratio + 0.051*LWL in feet
This equation says that anything that looks vaguely like a modern sailboat can manage to make good 2.62 knots on average no matter what its other characteristics might be. This is reasonable in light of the fact that ‘drift’ speed seems to be between 1 and 2 knots: Hugh Vilhen averaged just under a knot crossing the Atlantic in 5'4" Father’s Day, and Thor Heyerdahl and his crew of scientists floated from Peru to the Tuamotus at an average speed of just under 2 knots on the raft Kon-Tiki. Beyond that, IMS rated speed correlates to waterline length and the sail area to displacement ratio. An increase of five points in SA/D ratio, say from 15 to 20, will, on average, result in an increase of a third of a knot of boat speed (5*0.066=0.33) or 8 nautical miles per day; and an increase of five feet in waterline length will, on average, result in an increase of a quarter of a knot (5*.051=0.255) or 6 nautical miles per day, very close to what we found in analyzing the Bermuda Race and ARC data. Because it’s based on IMS data, which assumes a certain wind profile, boats will do better than this average on breezy, downwind passages and worse on light air or windward passages.