How do you log your miles.....

[aquaholic]

Used to have an old b/w gps that showed distance traveled, new raymarine e7 chart plotter does not show this unless linked to a raymarine log unit, I have a clipper distance log but if I am correct in thinking this won't be accurate as it doesn't take in effect of tide etc, all I want to know is how many miles I have done. Any ideas?

 

[Spyro]

Used to have an old b/w gps that showed distance traveled, new raymarine e7 chart plotter does not show this unless linked to a raymarine log unit, I have a clipper distance log but if I am correct in thinking this won't be accurate as it doesn't take in effect of tide etc, all I want to know is how many miles I have done. Any ideas?

How accurate do you need it to be? My Raymarine log shows total distance and trip distance, yes it doesn't take into account tides but it will avaerage out over a longer period. I would say it is more important to have it calibrated correctly with the gps but that needs to be done at slack water.

 

[Pye_End]

Using a log. I do not subscribe to the idea that logs are superfluous.

If you use the GPS and work the tides efficiently you could over cook your miles sailed by maybe 20%. Not that this really matters for personal record keeping, but a log is very useful from a navigational point of view.

 

[little_roundtop]

Using a log. I do not subscribe to the idea that logs are superfluous.

+1 for recoding distance off the log.

 

[VicMallows]

+1 for recoding distance off the log.

Not if my experience with thru-hull logs is anything to go by. They seem to randomly stop working for random periods of time due to fouling.

 

[ukmctc]

measure off the chart, or if you want to make a rough guide use the gps or your log.
then just add it up on your log book daily. keep a running total.

 

[mireland]

measure off the chart, or if you want to make a rough guide use the gps or your log.
then just add it up on your log book daily. keep a running total.

+1

 

[Viking]

measure off the chart, or if you want to make a rough guide use the gps or your log.
then just add it up on your log book daily. keep a running total.

Yes! the proper way of doing it!

 

[KellysEye]

We also measure the chart. Although you can't do that on ocean passage charts thus we used GPS positions.

 

[alahol2]

When I had a trailing log I always used the log trip distances. When I got a through hull log I found that the thing would stop working at random intervals and certainly by half way through the season it would give up completely. I now use the trip meter on the GPS (but it does feel wrong). I feel cheated if I've sailed 30 miles through the water but only 25 over the ground.

 

[VicMallows]

I am now wondering why anyone particularly wants to know how far they've been. I know we are required to have a passage PLAN - even if only in our heads.........but I am nor aware of any requirement to keep a record of the passages we have successfully completed?

 

[LadyInBed]

I used to use S&D log but it was of very dubious accuracy.
Last year I started using the Chart Plotter log, probably a bit more accurate but it's only an approximate indicator.

 

[HinewaisMan]

It depends what you want to measure – how far you have gone or how far you have been through the water.

We measure with a running total by GPS measured distance covered AND by log. I’m not on the boat at the moment, but if I remember rightly, to date our distance measure is c.18,800nm (ish) from Australia to the UK, log is about 10% less.

So if that’s right, since leaving home, we’ve covered c.18,800nm, but the boat has only passed through c 16,500nm of water thanks to currents/tides.

But the log is measured through a paddle wheel that is prone to getting gunked up.

So we are measuring our journey based on Distance Over Ground, not Log.

 

[sailor211]

We also measure the chart. Although you can't do that on ocean passage charts thus we used GPS positions.

Why not

 

[mcframe]

It depends what you want to measure – how far you have gone or how far you have been through the water.

We measure with a running total by GPS measured distance covered AND by log. I’m not on the boat at the moment, but if I remember rightly, to date our distance measure is c.18,800nm (ish) from Australia to the UK, log is about 10% less.

So if that’s right, since leaving home, we’ve covered c.18,800nm, but the boat has only passed through c 16,500nm of water thanks to currents/tides.

How much further has the mast truck travelled (through the air) than the bottom of the keel (through the water)? ;->

 

[johnalison]

With a mast height of about 20 metres above the keel, travelling around the world will give it Pi times 40 metres extra or about 130 metres. The size of the Earth makes no difference.

 

[Blueboatman]

I have been known to use the Walker log to recalibrate the thru hull one

 

[William_H]

I am now wondering why anyone particularly wants to know how far they've been. I know we are required to have a passage PLAN - even if only in our heads.........but I am nor aware of any requirement to keep a record of the passages we have successfully completed?

I agree Vic it is only for bragging rights. My personal total of sailing distance would be calculated by years of sailing multiplied by usual number of voyages (races) per year multiplied by usual race distance. But then it doesn't matter anyway. olewill

 

[mcframe]

With a mast height of about 20 metres above the keel, travelling around the world will give it Pi times 40 metres extra or about 130 metres. The size of the Earth makes no difference.

Hehehe - I can see that was too easy for you (See the "rope around the world, then add 1 metre" question).

OTSO random applied nav/math questions, here's one that kept me amused for a couple of mins last year:

An Airbus A320 leaves (departs the stand) Zurich airport (47 deg 22 min N) bang on local sunset early Nov, and takes 5 minutes to clear the runway. It then flies 300 deg(true) towards LHR at a height of 20,000 feet at a speed of 600 knots.

Question: does a pax on seat 3A see another sunset?

i.e. What's the speed of sunset? vector the course & allow for altitude; approximations are better than nothing.

 

[aquaholic]

I have now found the function on the plotter that records gps log and trip, but would agree the best way is to measure off the chart during a passage.