speedometer vs. GPS

OCDACTIVE · 06-03-2010, 10:09 AM

ishoot308, great explaination of the gps speed. I have seen in many situations that in a slight turn it will actually show a greater speed then the true speed. This is why when racers are trying to break speed records they have to complete two passes to ensure accuracy.

My gps speedo needs a new battery, but livorsi wants $200 to do the replacment. However, there is no law that I have to have a speedo on the boat. So frankly I don't know how fast or slow I am going. Would be very hard to make that stick in court.

VtSteve · 06-03-2010, 11:28 AM

On Saturday, I tested mine out. The speedo is accurate up to around 45 to almost 50, then it goes my way

I will be testing the Garmin against the Tom Tom next weekend. As of now, the best GPS I have in my boat is the iPhone, with a $9.95 Navionics East app in it. I can see everything better, including the marker buoys, than with the Garmin 440. Interestingly, I have the optional $200 card in the Garmin.

brk-lnt · 06-03-2010, 11:32 AM

Quote:

Originally Posted by OCDACTIVE

My gps speedo needs a new battery, but livorsi wants $200 to do the replacment. However, there is no law that I have to have a speedo on the boat. So frankly I don't know how fast or slow I am going. Would be very hard to make that stick in court.

$200? Depending on the model, that is like 70-80% of the price when new. You should bring it by, my guess is the battery could be replaced for about $10.

OCDACTIVE · 06-03-2010, 11:56 AM

Quote:

Originally Posted by brk-lnt

$200? Depending on the model, that is like 70-80% of the price when new. You should bring it by, my guess is the battery could be replaced for about $10.

I have been online and apparently if you send it back to livorsi they give you a new model for $200 as an exchange. I have been told I can run a line to my new GPS once I get the network up and running which may negate the need to replace the battery or unit at all.

But frankly, I don't care what speed I am at. I am driving safe and prudent. Until there is a law that says I have to have a speedo it really doesn't matter.

Excalibur · 06-03-2010, 12:27 PM

I put a portable GPS in my boat for a weekend and wrote down the tachometer revolutions for particular speeds.
My pitot tube kicks up over 60 on Lake Winnisquam..

lawn psycho · 06-03-2010, 01:42 PM

My speedometer sucks. It doesn't even read until about 25 MPH and then when it does, it's off by 10MPH when compared to my GPS.

However, my boat tops out at 48.5MPH according to my GPS, and that's on flat water with only two people. I don't see a ticket in my future anytime soon

06-03-2010, 10:09 AM	#1
OCDACTIVE Senior Member Join Date: Feb 2009 Location: Fort Myers FL / Moultonboro Posts: 1,045 Thanks: 444 Thanked 574 Times in 178 Posts	ishoot308, great explaination of the gps speed. I have seen in many situations that in a slight turn it will actually show a greater speed then the true speed. This is why when racers are trying to break speed records they have to complete two passes to ensure accuracy. My gps speedo needs a new battery, but livorsi wants $200 to do the replacment. However, there is no law that I have to have a speedo on the boat. So frankly I don't know how fast or slow I am going. Would be very hard to make that stick in court. __________________ Have you had your Vessel Inspected Yet?

06-03-2010, 11:28 AM	#2
VtSteve Senior Member Join Date: Apr 2008 Posts: 1,320 Blog Entries: 1 Thanks: 230 Thanked 361 Times in 169 Posts	On Saturday, I tested mine out. The speedo is accurate up to around 45 to almost 50, then it goes my way I will be testing the Garmin against the Tom Tom next weekend. As of now, the best GPS I have in my boat is the iPhone, with a $9.95 Navionics East app in it. I can see everything better, including the marker buoys, than with the Garmin 440. Interestingly, I have the optional $200 card in the Garmin.

06-03-2010, 12:27 PM	#5
Excalibur Senior Member Join Date: Jul 2004 Location: Gilford,NH is where I would like to be and Southborough, MA is where I have to be Posts: 90 Thanks: 15 Thanked 11 Times in 4 Posts	I put a portable GPS in my boat for a weekend and wrote down the tachometer revolutions for particular speeds. My pitot tube kicks up over 60 on Lake Winnisquam..

06-03-2010, 01:42 PM	#6
lawn psycho Senior Member Join Date: Jul 2009 Location: On the move... Posts: 987 Thanks: 113 Thanked 248 Times in 133 Posts	My speedometer sucks. It doesn't even read until about 25 MPH and then when it does, it's off by 10MPH when compared to my GPS. However, my boat tops out at 48.5MPH according to my GPS, and that's on flat water with only two people. I don't see a ticket in my future anytime soon