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Old 17 February 2012, 13:06   #1
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Most economical speed?

What is the most economical speed per mile to run at?

Is it the speed to maintain planing ability, whatever your boat/engine?

Or is it slightly quicker to have less boat in the water as long as you're not pushing your engine to its limits?

C'mon techies.
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Old 17 February 2012, 13:16   #2
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What is the most economical speed per mile to run at?
ow lorng didd yew sitt ther finkin 'wots de darftist kwestiun i cann axe'

ps yorr a still
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Old 17 February 2012, 13:27   #3
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Quite a while. Sat on a train from Birmingham. Glad to be leaving.

I guess though it's immaterial if I stay attached to a bouy anyway!
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Old 17 February 2012, 13:30   #4
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ps yorr a still
still aye nobbur yew mean? i fownd diss - doo yew fink itts is?
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Old 17 February 2012, 13:32   #5
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That would be a quality hat for the April Cruise!!
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Old 17 February 2012, 13:41   #6
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I've just made this box (for my non-rib boat!). It is connected to a fuel flow sensor in the fuel line that sends a pulse for every 0.4 ml of fuel that is used. The number of pulses, GPS speed and lat/long get logged to an SD memory card once per second. The SD card also contains a programmable calibration factor to change the 0.4ml to whatever it needs to be to be accurate.


By setting the initial fuel quantity it counts down as fuel is used.

It also generates a little scrolling bar chart of flow rate as it varies with time:


(and shows GPS position, speed, etc.,)

The plan is to use this data to find out exactly how fuel consumption varies with speed (it gets told ho many people are in the boat and the amount of fuel, so total mass is guessable). With enough data, I hope to be able to get a good idea of fuel burn rate vs speed and, if I can log it, r.p.m.

I know wind, tide, etc,., will affect speed over the ground, which is why I will get as much data as I can and weight the data with the number of points at each speed. The aim is to build up a 'map' of " fuel consumption rate" vs "speed" (and also generate KML for each trip that can be viewed in Google Earth).

It might not work in practice, but I'm sure going to give it a try!

The sensor is fuel-proof, air-tight, able to cover a wide range of flow rates and has no metal-to-metal contact. With only 5V going to it, I am confident it won't blow up on me. I just need to get the boat wet now..

Engineers, eh?!
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Old 17 February 2012, 13:48   #7
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[QUOTE="HUMBER P4VWL"]Quite a while. Sat on a train from Birmingham. Glad to be leaving.



And what's wrong with Birmingham yea Cheshire snob
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Old 17 February 2012, 13:48   #8
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I put it up before, but these are my findings.
The orange line shows the reach with a certain amount of fuel.
At 1000 rpm you get the furthest but it will take ages to get there.
The most economical speed is between 3000 and 4000 rpm though. In my case anyway.

The blue line shows the speed and the pink line the fuel used.
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Old 17 February 2012, 13:50   #9
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Quote:
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doo yew fink itts is?
nar. dis iz iz att

Quote:
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That would be a quality hat for the April Cruise!!

wot wiv yew an dat kirny nobbur inn iz ledderhosen wot wil de welch peepuls fink
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Old 17 February 2012, 14:02   #10
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Quote:
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nar. dis iz iz att

wot wiv yew an dat kirny nobbur inn iz ledderhosen wot wil de welch peepuls fink
You crack me up fishy
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