Speedometer dilemma

metriccrescentwrench

metriccrescentwrench

Commander
Joined
Oct 22, 2007
Messages
2,598
Depending on loading and conditions my boat tops out at around 65 mph, so I've got an 80 mph speedometer in it. I spend a lot of time pulling my son on a wakeboard or skis, and I'm sure I'll be hounded into pulling a tube this summer also. The problem is that with the 80 mph speedometer I just about need a magnifying glass to read the speed when we're doing watersports because the low end of the dial is so compressed, so it's a real struggle to give anyone a good steady speed.

I'm very close to deciding to put in a 60 mph speedometer just so I can get more resolution at the low end of the range, and when I'm hauling butt not worry about the speed and just be satisfied that we're going fast. I'm a little worried about that though - I know that most industrial pressure gauges can typically handle a small amount of overpressure before they're damaged. Does anyone know if that holds for boat speedometers as well (since they're really nothing but a pressure gauge with a dial marked in mph).
 
R

rbh

Fleet Admiral
Joined
Mar 21, 2009
Messages
7,939
Re: Speedometer dilemma

How about using some white out to put a line on the gauge that you can see clearly, that would be the cheap fix.
 
metriccrescentwrench

metriccrescentwrench

Commander
Joined
Oct 22, 2007
Messages
2,598
Re: Speedometer dilemma

rbh said:
How about using some white out to put a line on the gauge that you can see clearly, that would be the cheap fix.
Click to expand...

Well, it's more a matter of resolution. With the 80 mph speedometer the width of that white line would be at least 5 mph for the speeds wakeboarders want to be pulled. I like to be able to hold speed within 1 or 2 mph at most when I'm pulling someone.
 
Chinewalker

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Speedometer dilemma

You could add a second speedometer... More gauges might even look cool!
 
coolbri70

coolbri70

Lieutenant Commander
Joined
Oct 6, 2011
Messages
1,554
Re: Speedometer dilemma

I like gps gives a nice digital display
 
U

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
Re: Speedometer dilemma

A GPS Speedometer will go in the same hole.

The dial will then be linear instead of exponential like the pressure Speedos.
A 60 mph Pressure Speedometer is still going to have 42 mph at mid scale and 30 at 1/4 scale.
 
D

Dawg'sLife93

Petty Officer 1st Class
Joined
May 4, 2013
Messages
245
Re: Speedometer dilemma

I just bought an old Garmin GPS at a pawn shop for 20.00 bucks, It has just a 4" speedo option and it sucky cups to my windscreen. The maps for roads are out od date by 4 years, but who cares. I'll work great in the boat.
 
M

MolsonCanadian

Petty Officer 2nd Class
Joined
Jul 9, 2010
Messages
199
Re: Speedometer dilemma

I use a free iPhone app. All it displays is a large readout either in KPH, MPH or knots.
 
H

H20Rat

Vice Admiral
Joined
Mar 8, 2009
Messages
5,201
Re: Speedometer dilemma

Do you boat on a river with any current? If so, a gps speedo is useless... The river i wakeboard on has about 2.5mph of current, so if the driver tried to use that while i'm wakeboarding and tried to drive 20.5 mph, i'd be going downstream at 18 mph, and would then speed up to 23 mph on the return trip upstream. Long story short, if that applies to you, a gps wont' be any better than your current gauge.

So if it were me and a gps wasn't an option, the first thing I'd try is just run the gauge and see what happens. Keep in mind your gauge might start spraying water, so if you have electronics by it, you may want to try it outside of the dash first. If it does blow up on you and leaks, you can get really cheap solenoid valves, put one inline that you can control via a switch on the dash. For high speed runs, flip the switch to disconnect the speedo from the line.
 
You must log in or register to reply here.
Top