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29-07-2009, 08:39 PM
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#1
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Registered User
Country: uk
Location: barrow in furness cumbria
Occupation: letting agent
Boat name: fantastic
Boat make: phantom 18
Engines: mercury 2.4
Cruising area: walney
Join Date: Mar 2009
Location: barrow in furness cumbria
Posts: 237
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speedometer
looking for somet to give me a good reading on speed for a speed power boat . what can you recommend looking for value for money
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dont fight with ugly people they have nothing to lose
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29-07-2009, 08:44 PM
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#2
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Registered User
Boat make: Burgess
Join Date: Feb 2008
Posts: 60
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Gps
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29-07-2009, 08:59 PM
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#3
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Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
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GPS & I use this puppy
combines Speed ,Volt, RPM & compass all in the one unit - also has a gps output for any repeater if you wanted to run one
http://nordskogperformance.net/produ...&cat=22&page=1
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At least 75% of people who read this will try to lick their elbow!
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29-07-2009, 09:27 PM
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#4
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Registered User
Join Date: Jun 2009
Posts: 670
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Quote:
Originally Posted by rob m
looking for somet to give me a good reading on speed for a speed power boat . what can you recommend looking for value for money
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ive just got an old navman in mine (non-marine)..very accruate speed reading but city and town maps usless
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29-07-2009, 09:51 PM
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#5
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numbskull
Country: United Kingdom
Location: South
Occupation: none
Interests: none
Boat name: Leviathan
Boat make: Phantom 28
Cruising area: South Coast
Join Date: Mar 2004
Location: South
Posts: 15,959
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GPS is great, because you can run in a fast tide, then bullshit, but not bullshit about how fast ya boat is.
Buy a Gaffrig or Livorsi pitot and hold your head high when you tell people what speed ya boat does.
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29-07-2009, 10:31 PM
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#6
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Registered User
Country: Ireland
Location: Dublin
Occupation: Boatbuilder
Boat make: Hydrostream V-king, 650SS OCR ,Ring 21, Ring 18, Phantom 18.
Engines: 300Hp Mercury 2.4, 130 Yamaha, Bridgeport EFI, XR6, Merc 200.
Cruising area: Malahide, Dublin
Join Date: May 2004
Location: Dublin
Posts: 1,803
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Quote:
Originally Posted by Jon Fuller
Buy a Gaffrig or Livorsi pitot and hold your head high when you tell people what speed ya boat does.
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How accurate are the Gaffrig/Livorsi pittot ones Jon?
Alan
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29-07-2009, 10:56 PM
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#7
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numbskull
Country: United Kingdom
Location: South
Occupation: none
Interests: none
Boat name: Leviathan
Boat make: Phantom 28
Cruising area: South Coast
Join Date: Mar 2004
Location: South
Posts: 15,959
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Quote:
Originally Posted by Hydrostream
How accurate are the Gaffrig/Livorsi pittot ones Jon?
Alan
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My experience is that they're excellent.
When we've been on Windermere, they're been absolutely bang on with the official speed. We indicated 79-1/2 mph in the yellow extreme (virtually full scale on a 80mph Gaffrig), and the official speed was 79.37mph.
When I've done very honest 2 way runs on southampton water with my boat, again it's been spot on. a 2-way gps average agrees within a gnats cock of the Gaffrig reading.
In both cases we've used the in-built pitot pickup in the Bravo drive, not a transom mounted pitot. The drive version is good and deep in the water away from the running surface.
It seems to be human (powerboater) nature to always quote the highest speed they've ever seen on their gps as their 'top' speed, which is rarely an accurate figure for the boat. When my Gaffrig says 70, I'm comfortable it's actually doing 70, or fecking close to it.
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29-07-2009, 11:09 PM
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#8
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Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
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Quote:
Originally Posted by Jon Fuller
GPS is great, because you can run in a fast tide, then bullshit, but not bullshit about how fast ya boat is.
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Quite correct - more of a problem on a displacement hull
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It is impossible to lick your elbow.
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At least 75% of people who read this will try to lick their elbow!
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29-07-2009, 11:12 PM
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#9
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Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
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Nuts Edit Time Out.
Pitot measures speed over/through the water - GPS over the Earth surface - each has it's shortcomings & advantages
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It is impossible to lick your elbow.
Team25Racing.com
At least 75% of people who read this will try to lick their elbow!
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29-07-2009, 11:31 PM
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#10
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numbskull
Country: United Kingdom
Location: South
Occupation: none
Interests: none
Boat name: Leviathan
Boat make: Phantom 28
Cruising area: South Coast
Join Date: Mar 2004
Location: South
Posts: 15,959
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Quote:
Originally Posted by BluFin
Quite correct - more of a problem on a displacement hull
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a 4 mph following tide adds 4 mph to your gps speed, whether you're going at 5 mph, or 105 mph.
BTW, I was being facecious.
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30-07-2009, 12:22 AM
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#11
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Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
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Quote:
Originally Posted by Jon Fuller
a 4 mph following tide adds 4 mph to your gps speed, whether you're going at 5 mph, or 105 mph.
BTW, I was being facecious.
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So was I
There are +ve & -ve to both. But interestingly when you make a record attempt it's between two fixed points on the surface of the earth (typical 1Km). They don’t shorten or lengthen it because of the tide or wind & no correction is made in respect of that in the attempt unless it's athletics.
Time between two fixed points. You can play off the numbers one way or another depending on the perspective that the individual prefers, both work, both effective, both have error margins situation dependant.
It's only a bona fide timed run that counts for speed anything else it's just a ball park unverified number by an uncertified instrument that is only installed as an aid to navigation.
Gezz the guy only asked about speedos
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It is impossible to lick your elbow.
Team25Racing.com
At least 75% of people who read this will try to lick their elbow!
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30-07-2009, 12:24 AM
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#12
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Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
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Quote:
Originally Posted by Jon Fuller
Buy a Gaffrig or Livorsi pitot and hold your head high when you tell people what speed ya boat does.
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Oh thats speed through the water not between two fixed points
__________________
It is impossible to lick your elbow.
Team25Racing.com
At least 75% of people who read this will try to lick their elbow!
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30-07-2009, 12:49 AM
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#13
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numbskull
Country: United Kingdom
Location: South
Occupation: none
Interests: none
Boat name: Leviathan
Boat make: Phantom 28
Cruising area: South Coast
Join Date: Mar 2004
Location: South
Posts: 15,959
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OK, so carry on kiddin yaself. no skin off my nose.
There's some fast flowing water in the CI's, mebbe worth a trip for team wam for a fake speed claim. (47mph)
'Through the water' is the hard bit.
Records are always two way, within the hour to try to 'cover up' all the problems with measurement of speed over ground.
GPS is a superb tool, but what we're all trying to achieve is speed over water, not ground.
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30-07-2009, 05:26 PM
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#14
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Engine tester
Country: united kingdom
Location: Southend on Sea
Occupation: Construction
Interests: Gin & Women
Boat name: motorvator
Boat make: Revenger San Marino / Sunseeker Camargue 46 / Phantom 18/19/600
Engines: 502 mercruiser / Detroit 550s / 115 ProXS / Anything Borrowed
Cruising area: Thames, Southend
Join Date: Nov 2006
Location: Southend on Sea
Posts: 1,021
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But shirley as any good nav knows, if an alternative route exists that adds say 2 nm to a journey but gains a tidal stream advantage of 4 knots and the race period is likely an hour then the alternative route is the no brainer.
So we are actually interested in getting between two fixed points on the globe in the shortest time possible regardless of speed through the water QED.
Or am I thinking too hard
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"Lend us a motor Chaos"
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30-07-2009, 05:59 PM
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#15
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numbskull
Country: United Kingdom
Location: South
Occupation: none
Interests: none
Boat name: Leviathan
Boat make: Phantom 28
Cruising area: South Coast
Join Date: Mar 2004
Location: South
Posts: 15,959
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Quote:
Originally Posted by motorvator
Or am I thinking too hard
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I think you should come out & show us.
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30-07-2009, 06:18 PM
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#16
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Registered User
Country: England
Location: Hampshire
Occupation: Credit Crunched
Interests: Rally Driving
Boat name: Double 2 Shirts
Boat make: Planatec 41
Engines: 2x625's+ From Uncle Sam
Cruising area: Solent
Join Date: May 2007
Location: Hampshire
Posts: 2,522
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Quote:
Originally Posted by Jon Fuller
I think you should come out & show us.
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I thought it was the distance travelled over the time taken to do the distance - forget speed through the water...
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30-07-2009, 06:22 PM
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#17
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Registered User
Country: England
Location: Hampshire
Occupation: Credit Crunched
Interests: Rally Driving
Boat name: Double 2 Shirts
Boat make: Planatec 41
Engines: 2x625's+ From Uncle Sam
Cruising area: Solent
Join Date: May 2007
Location: Hampshire
Posts: 2,522
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But these are the thoughts of a simpleton not a racer... and as far as i know that has been the definition of "Speed" for time immoral
For what its worth and what do I know anyway ........
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30-07-2009, 06:27 PM
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#18
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numbskull
Country: United Kingdom
Location: South
Occupation: none
Interests: none
Boat name: Leviathan
Boat make: Phantom 28
Cruising area: South Coast
Join Date: Mar 2004
Location: South
Posts: 15,959
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Quote:
Originally Posted by Pash 1
and what do I know anyway ........
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I think you can answer that.
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30-07-2009, 06:38 PM
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#19
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Engine tester
Country: united kingdom
Location: Southend on Sea
Occupation: Construction
Interests: Gin & Women
Boat name: motorvator
Boat make: Revenger San Marino / Sunseeker Camargue 46 / Phantom 18/19/600
Engines: 502 mercruiser / Detroit 550s / 115 ProXS / Anything Borrowed
Cruising area: Thames, Southend
Join Date: Nov 2006
Location: Southend on Sea
Posts: 1,021
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Quote:
Originally Posted by Jon Fuller
I think you should come out & show us.
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Ok Ok I'd like to announce to the forum I'm a closet lesbian , but what on earth did you want me to show you?
__________________
"Lend us a motor Chaos"
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30-07-2009, 07:23 PM
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#20
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Registered User
Country: England
Location: Hampshire
Occupation: Credit Crunched
Interests: Rally Driving
Boat name: Double 2 Shirts
Boat make: Planatec 41
Engines: 2x625's+ From Uncle Sam
Cruising area: Solent
Join Date: May 2007
Location: Hampshire
Posts: 2,522
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Quote:
Originally Posted by Jon Fuller
I think you can answer that.
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I did its distance over time......
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