photodog
Lord High Commander of Upper Broughton and Gunthor
Hahaha.. just because a Moody has never done 10 knots... doesnt means its not possible....!
10 knots in a Bavaria
- Thread starter Bav34
- Start date
fireball
Well-Known Member
It's because Bavarias are so light and flimsy ...
Bav34 has obviously emptied his ballast tanks (fuel & water) and sent the bulb of the keel on ahead (handy these shoal keels) ... so he's actually planning ...
Bav34 has obviously emptied his ballast tanks (fuel & water) and sent the bulb of the keel on ahead (handy these shoal keels) ... so he's actually planning ...
photodog
Lord High Commander of Upper Broughton and Gunthor
Here is a nifty little hull speed calculator... in case yer lazy....
http://www.sailingusa.info/cal__hull_speed.htm
A bav 34 .is nearly 36 feet... so thats about 8 knots.
http://www.sailingusa.info/cal__hull_speed.htm
A bav 34 .is nearly 36 feet... so thats about 8 knots.
BlueSkyNick
Well-Known Member
Bollox. The formula is based on LWL not LOA so its closer to 7 kts than 8.
QED
And no a Moody wouldnt go any faster either, its nowt to do with the manufacturer, if its a fully displacement hull not a planer.
fireball
Well-Known Member
I got 12 knots out of a 30'er with about 24' waterline length .... admittedly there was one wave at the pushpit and one at the pullpit .... oh and full sail in 25 knots broad reach ... I think that can technically be called surfing though ..
The Bav34 is 35' long. if the ratio is about the same as ours then the LWL will be about 33' which gives 7.7 knots theoretical hull speed - as we know, hull speed can be pushed beyond that, it just takes a lot more power - so 8 knots is certainly possible - given the right wind conditions.
The Bav34 is 35' long. if the ratio is about the same as ours then the LWL will be about 33' which gives 7.7 knots theoretical hull speed - as we know, hull speed can be pushed beyond that, it just takes a lot more power - so 8 knots is certainly possible - given the right wind conditions.
photodog
Lord High Commander of Upper Broughton and Gunthor
Bollox. The formula is based on LWL not LOA so its closer to 7 kts than 8
Yah, but with those two in the cockpit its gonna be draggin its transom and thats gotta add a bit eh?? (Lenght wise... but more drag as well..)
Anyways... a 34 is 28 feet LWL.... which puts the hull speed at just over 7 knots...
And us at around the same..... but we regularly see 7.5-7.8 knots on a reach.... (SOG on the GPS... no appreciable tide) so the angle of heel... how much of the backside is in the water... waves.. etc.. all have a effect...
Yah, but with those two in the cockpit its gonna be draggin its transom and thats gotta add a bit eh?? (Lenght wise... but more drag as well..)
Anyways... a 34 is 28 feet LWL.... which puts the hull speed at just over 7 knots...
And us at around the same..... but we regularly see 7.5-7.8 knots on a reach.... (SOG on the GPS... no appreciable tide) so the angle of heel... how much of the backside is in the water... waves.. etc.. all have a effect...
BlueSkyNick
Well-Known Member
Like photodog says, the LWL is about 28ft so theoretical hull speed is just over 7kts. Even taking into account all that you both say, its still a good way short of 10 innit!
Look at the GPS on the video - it ranges from 0.5 to 1.5 kts less.
Logs for through te water speed shouldnt be taken too seriouisly, IMO.
Look at the GPS on the video - it ranges from 0.5 to 1.5 kts less.
Logs for through te water speed shouldnt be taken too seriouisly, IMO.
blackdogsailing
Well-Known Member
There are a number of hull speed calculators on the web. The formula as previously stated is x times sq. root of waterline length. x is given as anything between 1.34 and 1.51, I presume for different hull shapes though I am not sure why the difference. To get 10 kts. you will need a waterline of about 43 feet 
bendyone
Well-Known Member
Well done, dont worry about the knockers it's a great feeling when your boats goes well.
grafozz
Well-Known Member
18.5 knots ... on GPS
With just 1/2 the jib out ...no main .... 52 knots of wind !.....flat sea , 500 metres offshore ......
using the hull speed calculator for 38 ft it should have been 16.52 knots ?
it is x 2 for a cat isn,t it ?.....
With just 1/2 the jib out ...no main .... 52 knots of wind !.....flat sea , 500 metres offshore ......
using the hull speed calculator for 38 ft it should have been 16.52 knots ?
it is x 2 for a cat isn,t it ?.....
jimi
Well-Known Member
Well I managed 12 knots in my Bennie 331 last week ... but that was surfing down waves off the Lizard ... the bum was a bit dirty or I think I could have managed more .. my record so far is 16 knots in a F7 in Christchurch Bay.
phatcat1
Well-Known Member
10 knots!
Is that all!
Check this out from our summer trip across to Vlissengen - This was our max mind you, not the average!
Is that all!
Check this out from our summer trip across to Vlissengen - This was our max mind you, not the average!
fireball
Well-Known Member
I think that's what raymarine max out at - cos ours showed that on our way back from Poole in a F2-3 beam reach!
Ken_Irby
N/A
10kts shown when you scrolled to "MAX"?
this means that for an instant only the boat was travelling at 10kt through the water. she would of course need to have been planing since this is above her hull speed. i have seen 13.2 on our similar instrument after a hairy down-wind run in the gulf of corinth regularly surfing down the waves but can't remember actually observing it at the precise moment. the average speed might be quite modest. your log appears to be a bit optimistic when compared to the gps but in tidal waters it isn't possible to be sure on that. judging by the bow wave you are probably very near to theoretical max speed for a displacement boat (assuming lwl=30')
Chas on Kentrina's login therefore not necessarily her views
this means that for an instant only the boat was travelling at 10kt through the water. she would of course need to have been planing since this is above her hull speed. i have seen 13.2 on our similar instrument after a hairy down-wind run in the gulf of corinth regularly surfing down the waves but can't remember actually observing it at the precise moment. the average speed might be quite modest. your log appears to be a bit optimistic when compared to the gps but in tidal waters it isn't possible to be sure on that. judging by the bow wave you are probably very near to theoretical max speed for a displacement boat (assuming lwl=30')
Chas on Kentrina's login therefore not necessarily her views
Quandary
Well-Known Member
10 Knots in a Bav34?
I am up for your challenge anytime, unfortunately I havent got a Sigma of either size just now, but I still have all the trophies.
How much time are you willing to give my Finngulf 33?
I used to find that racing handicaps give a fair indication of boat speed, we are rated in the same class up here as the Bav 48s (but we cannot beat one of them over the water in wind above force 4 ) the other one we never see.
In 2007 we set off down Loch Ness in the Sigma 38,following wind built steadily from 25 to 39 knots,no gusts at all, nearly flat water with no real waves to surf on, one reef with preventer no.2 genoa boomed out, we never managed to exceed 9.2 knots.
Last year in the F33 broad reaching in the Sound of Sleat in 12-16 knots at 6.2 kts we were overtaken by a Norwegian fish farm boat, climbed on it lovely stern wave and honked along at 12 kts. for several minutes but the dog did not like it so (with difficulty) we jumped off.
I am up for your challenge anytime, unfortunately I havent got a Sigma of either size just now, but I still have all the trophies.
How much time are you willing to give my Finngulf 33?
I used to find that racing handicaps give a fair indication of boat speed, we are rated in the same class up here as the Bav 48s (but we cannot beat one of them over the water in wind above force 4 ) the other one we never see.
In 2007 we set off down Loch Ness in the Sigma 38,following wind built steadily from 25 to 39 knots,no gusts at all, nearly flat water with no real waves to surf on, one reef with preventer no.2 genoa boomed out, we never managed to exceed 9.2 knots.
Last year in the F33 broad reaching in the Sound of Sleat in 12-16 knots at 6.2 kts we were overtaken by a Norwegian fish farm boat, climbed on it lovely stern wave and honked along at 12 kts. for several minutes but the dog did not like it so (with difficulty) we jumped off.
myoldsailor
Well-Known Member
come on..weour all thinking it...
still looks like a boring yacht to sail.
still looks like a boring yacht to sail.
andygc
Well-Known Member
Not at all. Hull speed is not an indication of maximum speed in a displacement boat but is merely an estimate of the speed at which the wave-making resistance increases substantially. You can easily exceed notional hull speed by adding power - it just needs a lot. There is a short article in Wikipedia with a nice illustration of a steam yacht running at three times its notional hull speed - and it is not planing - just Google "hull speed".
The Type 23 frigate has an overall length of 436 feet, but according to the calculator mentioned above would need a waterline length of 660 feet to reach the 34.4 knots recorded by HMS Sutherland in 2008. It doesn't plane, but it does have a couple of RR Speys.
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doug748
Well-Known Member
I saw 11.5 kts on the GPS this summer, in 25kts from the beam.
Not bad for a Contessa 32 and quite enough for me.
Not bad for a Contessa 32 and quite enough for me.
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barfly4657
N/A
Worth running that Measured Distance in Southampton Water a few times to calibrate your log - then perhaps local peeps would stop telling porkies!
doris
Well-Known Member
eight inches
Ah the joy of numbers. Bet there are a few chaps on this thread whose wives have a problem getting the car through a width restrictor.
'But darling if this is 8 inches then surely there must be plenty of room!'
Ah the joy of numbers. Bet there are a few chaps on this thread whose wives have a problem getting the car through a width restrictor.
'But darling if this is 8 inches then surely there must be plenty of room!'