your boat, and how fast she goes

Snapdragon 24

Sail - Best ever 6.2 on the log, confirmed by GPS. More usually 4 - 5knts off the wind
Motor (28hp*) 7.2 flat out with a clean bum, but that's just a waste of diesel. Being sensible, 5 - 5.5.




*Yes, I know. But it was what was available at a price (£0) I could afford when I needed it!
 
There are always two answers...

...when asking questions of how fast any particular yacht will go/how close she will point

1. Is the Yacht Club Bar answer - often delivered after a couple of beers safely on dry land, with other "competitive" answers from others standing at the bar in the offing and most importantly with no immediate way of checking

2. The actual speed/pointing acheived in real conditions on the water - actually doing it there and then and consistently.

The wise reader will have to scan through the answers to these posts and decide for themselves which catergory each reply fits into

The nice think about the first answer is you don't even need a boat - spout that you can make 17 knots to windward on a steadfastwiggle 29 with enough aplomb and in the right setting someone might believe you...
 
Uphams Waterbug (1950s wooden cutter)
On a beam/broad reach, sustained 7.8knots
Wind ahead of the beam, 6.3 knots
Hard on the wind, 5.5knots

Stuart Turner P55 = 3.2 knots cruising speed, 3.8 knots sustained "high speed", 4.2knots @WOT (max 5 mins, before it starts coughing).

Yeah - I sail everywhere unless it is flat calm!!!
 
Stemar said:
Snapdragon 24

Sail - Best ever 6.2 on the log, confirmed by GPS. More usually 4 - 5knts off the wind
Motor (28hp*) 7.2 flat out with a clean bum, but that's just a waste of diesel. Being sensible, 5 - 5.5.




*Yes, I know. But it was what was available at a price (£0) I could afford when I needed it!
Click to expand...

i have 31 ft WL & only manage 7.5kts (Max Boat speed NOT SOG ) with a clean bottom,what the hell is wrong with my boat :mad::mad:
 
sailorman said:
i have 31 ft WL & only manage 7.5kts (Max Boat speed NOT SOG ) with a clean bottom,what the hell is wrong with my boat :mad::mad:
Click to expand...

I doubt there is anything wrong with your boat fella. The 'problem' is more likely to be:

honesty
you've actually taken the trouble to calibrate your log
 
Get past the intro and watch this J109 and note the speeds on the log!

http://www.youtube.com/watch?v=13bo7-pUQ5w

Otherwise, 1.34 x sq rt of LWL in feet is the usual hull speed formula but can be exceeded in perfect conditions with a lot of power be that sail or motor provided that the wind direction and seastate are not themselves the limiting factor. The constant 1.34 is not written in stone however and with enough power can be stretched even to 1.5 on slippery boats. Our record was 19.1kts but that was surfing, usual max 8.5kts 41ft cruiser racer 36ft plus LWL (under way, less when static), theoretical hull speed 8kts but nevertheless we could do 8.5kts flat out under 44hp engine. Under sail in perfect conditions off the wind (not surfing) 9kts was common, 10kts occasional. Upwind optimum was 7kts at 28 degrees apparent.

Our log was fully calibrated and all figures are boatspeed not SOG.
 
Robin said:
Get past the intro and watch this J109 and note the speeds on the log!

http://www.youtube.com/watch?v=13bo7-pUQ5w

Otherwise, 1.34 x sq rt of LWL in feet is the usual hull speed formula but can be exceeded in perfect conditions with a lot of power be that sail or motor provided that the wind direction and seastate are not themselves the limiting factor. The constant 1.34 is not written in stone however and with enough power can be stretched even to 1.5 on slippery boats. Our record was 19.1kts but that was surfing, usual max 8.5kts 41ft cruiser racer 36ft plus LWL (under way, less when static), theoretical hull speed 8kts but nevertheless we could do 8.5kts flat out under 44hp engine. Under sail in perfect conditions off the wind (not surfing) 9kts was common, 10kts occasional. Upwind optimum was 7kts at 28 degrees apparent.


I know and understand what you are saying ,unfortunately there are a few on here that will make out you are lying / exaggerating.
We had this conversation 7-8 years ago regarding boat speed through a moving wave of water if you can remember .
I frequently make 8.5 -10 kts boat speed in 16 -22 kt wind speed on a reach and there is little tide or much current out here, my log does not work, but we do have three GPS/plotters on board

I cannot understand Quandary as when I did CS ? YM in Conwy they had a Sigma 38 or 40 "Mistral" I think it was called and that boat was often going into double digit boat speeds
Click to expand...
 
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1997 Bav 46 Exclusive.

LOA 46 ft
LWL 42 ft

Do 9 kts +- a tinge sailing

78 HP Volvo = 9 KTS flat out.

What is the formula for hull speed??? (8.9 kts.) As per formula. I never lie. :D
 
Sabre 27, twin keel

Beam reach 5.9 knots,
8.5 surfing (scary!)

Under power 5.8 knots max (3500 rpm),
4.8 knots sensible (2600 rpm)

The log has NOT been calibrated
 
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sailorman said:
i have 31 ft WL & only manage 7.5kts (Max Boat speed NOT SOG ) with a clean bottom,what the hell is wrong with my boat :mad::mad:
Click to expand...

You've got a sensible engine, not double what anyone could reasonably want! Jissel's grossly overpowered, but it does come in handy getting back into Portsmouth against a spring ebb!

Hull speed's around 6 knots, so any more is just a waste of fuel, but it's fun to upset the Sunsail boats that think they're quicker than me, once in a while.
 
If you are interested in hull speed, have a read of Bethwaite's 'High Performance Sailing', some interesting graphs for various hull shapes. Also Larrson and Elliason's Principles of Yacht Design. Basically what was a brick wall with older designs has become more of a ramp with modern hulls. And very thin (catamaran) or very light flat hulls don't apply.
My Lightwave 395 never seemed to get very high numbers on the log, but our best Round The Island Race was under 7 1/4 hours, FWIW. A big difference between cruising sails and racing rig with 9 bodies on the rail. Beating you could get 8knts on the B&G in race mode, with say 20knts over the deck, ie. F4. But then we never took the number too seriously, just used them to look for best speed/pointing compromise.
Under engine very dependent on how clean the bottom was, I think it would do 7kts if you could stand the noise, Yanmar 3GM, possibly not optimal prop. 5knts was more relaxing and used very little fuel.

How many people have managed to calibrate their logs? I never quite trusted mine to be the same on both tacks and I'm sure that the cal went bad at higher speeds, this might just be that it averages over a different time frame to the gps?
Has anybody ever sailed on a boat where the true wind indicated does not change as you bear off at the windward mark? I think the G in B&G stood for 'Guesswork'. The B would be censored on here.


edit. I'm not slagging B&G so much as people who believe the numbers to 1% or whatever, B&G instruments are better than most, especially if they are free with a used boat!
 
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benlui said:
What make and model is your boat, and what’s her fastest speed underway both by sail, and by motor?

For under sail, assume no run of tide, a flat sea, and quote your max speed before you need to take in your first reef.

For Example
Shipman 28
beam reach, 7-8kts
motor, max speed 7-8kts (nanni diesel 21hp)
Click to expand...

When I first spotted this thread I thought that it would bring out the optimists and sure enough in post no 1 it does so.

I race against a Shipman 28 regularly week after week. It is well sailed and it wins some races. But there is no way ( and data is recorded off the Garmin) that it sails at the above speeds. If it did, it would win every race.
 
Hallberg Rassy 34. As has often been said here, HRs are incredibly slow. I calibrate my log to read about 0.1 knot fast at 6.5 knots, but it overreads a bit more when faster.

Max comfortable reaching speed - about 7.5
Optimum close-hauled 5.9
Max ever - 11.5

The right-hand column here shows distance over ground every half-hour on a dead run in the Baltic, with at the most 1/4 knot current on that day. You will see that speeds of around 7 knots were maintained for quite a while. Small jib & no spinnaker; about 20 knots true wind.
66.jpg
 
Beneteau First 435. Calibrated log on 2 runs, measured half mile in perfect conditions 8.2 kts, 17 kts apparent about 65 degrees. I usually think if I'm doing 8 kts. that is pretty much it. Under power, 50 hp perkins at 2500 rpm and a pathetically small prop 6.2 kts !!!

Chris
 
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