Measuring temp in the Gulf Stream

[La Vie Dansante]

I'll be sailing up the Gulf Stream this month, from Key West to St. Simon's. In order to hug the western wall, I'd like to measure the sea surface temp along the way. Do digital laser IR thermometer guns work for this purpose, or should I tow something?

[Paul L]

If you have a saltwater pump at the galley you can pump seawater into a cup and use the IR thermometer to get a reasonably close temp reading.

[billknny]

If the instruments on your boat are capable of showing you set and drift, (and based on you boat, I would guess they are...) that will actually be a more immediate and helpful way of doing what you are trying to do.

I have a transducer that gives me ocean surface temperature, and I find it useful for fishing, but for staying in the gulf stream you'd be better off monitoring the current rate and direction.

[RaymondR]

A lot of fish finders also display water temperature and some of them have nmea output which might let you log temperature on a computer.

[psk125]

We used to fill a bucket from over the side and stick a thermometer in it. Not complicated.

[mvmojo]

Off shore racing to Bermuda, racers fill the toilet bowl with water and drop in a pool thermometer.

[boatman1]

No idea if a IR “gun” will work reliably tryin to measure sea surface temps. I think that the observation of temperature is certainly valuable for determining if you’re on or off the bus. The online stream forecasts are pretty good, so don’t neglect plotting where the west wall is. On one northbound voyage several years ago the stream took an almost 90 degree right(east) off Canaveral and didn’t head back north towards Hatteras for about a hundred or so miles. Baffled me at the time.

[Snore]

You are overthinking this. When SOG is greater than speed through water you are in it. From KW to West Palm/ Lake Worth Inlet, stay in 300 feet of water or more and yeeeehaw!

[psk125]

Originally Posted by Snore

You are overthinking this. When SOG is greater than speed through water you are in it. From KW to West Palm/ Lake Worth Inlet, stay in 300 feet of water or more and yeeeehaw!

Unless you stumble into an eddy and it starts pushing you the wrong way...

[maine50]

Yes the IR device will work fine. have use one several times thru the Gulf stream to bermuda or to caribbean.--Usually the depth meter will also have a temp reading.

[puffcard]

We came up from Bahamas two weeks ago and the West wall was cranking. Had over 3.5-4kts current at times. Made a 216nm day, that's a +9kts avg under just sail in a 37ft boat. We have a temp chart on the Garmin plotter, which works great to see small changes. My bet, it's so hot in the keys, may be hard to see temperature changes. We used the Gulf Stream predictor on Passageweather.com. It predicts the stream position for a couple days out. Print it out and layout waypoint coming up the coast. Like driving up I95.

[Snore]

Originally Posted by psk125

Unless you stumble into an eddy and it starts pushing you the wrong way...

Going up the coast that is a low probability. Then you would see SOG less than boat speed.