Graham376
Well-known member
Might be old data on your web browser, maybe try putting a ? at the end in the address bar
https://www.nasamarine.com/product/electromagnetic-log/?
On the page you link to, below the text you show, it says out of stock.
Electromagnetic log transducer.
- Thread starter doug748
- Start date
On the page you link to, below the text you show, it says out of stock.
Blue Sunray
Well-known member
:encouragement:
Let us know how you get on
+1
tean
New member
Okay ordered one from MES. £150 without the display.
GHA
Well-known member
vyv_cox
Well-known member
Lots of negative comments about traditional wheel type logs in this thread. I am most impressed with my new Airmar log/depth/temperature transducer. In combination with the B&G kit it provides an astonishing amount of data in combination with the GPS input, indicating the speed and direction of currents.
I painted the wheel and housing with one coat of Velox at the beginning of my season, launched April 29. The transducer has not been removed or cleaned in almost three months, photo shows it when removed on July 23.
I painted the wheel and housing with one coat of Velox at the beginning of my season, launched April 29. The transducer has not been removed or cleaned in almost three months, photo shows it when removed on July 23.
matt1
Well-known member
Lots of negative comments about traditional wheel type logs in this thread. I am most impressed with my new Airmar log/depth/temperature transducer. In combination with the B&G kit it provides an astonishing amount of data in combination with the GPS input, indicating the speed and direction of currents.
I painted the wheel and housing with one coat of Velox at the beginning of my season, launched April 29. The transducer has not been removed or cleaned in almost three months, photo shows it when removed on July 23.
Interesting! I got a new boat this year with the same transducer. Launched April and no problems at all (which is amazing for the Hamble - last boat would have fouled in weeks), even though the boat itself has grown a beard in the last fortnight!
Not sure that it was antifouled with anything....but maybe it was
lw395
Well-known member
It's easy to remove the log unit and clean it, but it still runs slower as the hull grows a layer of slime.
Will this affect the electromagnetic units the same , or do they penetrate beyond the boundary layer?
I think good AF on the hull will slow growth on the paddle wheel nearby.
Will this affect the electromagnetic units the same , or do they penetrate beyond the boundary layer?
I think good AF on the hull will slow growth on the paddle wheel nearby.
tean
New member
It is of course very easy to remove and clean a log, but it always produces a fountain that even if I get the cap on quick allows a good few liters of sea into the bilge. That might not be a problem if you have a leaky boat that routinely gets salt water in the bilge but it's a pain if like me, you're a fussy sort who is a bit OCD about having clean, dry bilges. That amount of water won't get my pumps particularly interested and so I'll have to mop it out by hand. And then I'll feel the need to rinse it all with freshwater to get rid of the salt. And mop that out too. It all becomes too much of a faff and so I don't bother and the log remains fouled until the next time I dry the boat out.
I remember years ago I had a boat with a Navico log that had a spring loaded valve in the skin fitting that helped a lot but haven't had that luxury for a while now.
Perhaps the EM log will turn out to need cleaning just as often. It appears to have electrical contacts on it that presumably have to connect to the water. Presumably it won't work if they get fouled with sea stuff. Who knows? Nobody on this forum by the looks of it, so I've taken the punt and will try to rectify that.
I remember years ago I had a boat with a Navico log that had a spring loaded valve in the skin fitting that helped a lot but haven't had that luxury for a while now.
Perhaps the EM log will turn out to need cleaning just as often. It appears to have electrical contacts on it that presumably have to connect to the water. Presumably it won't work if they get fouled with sea stuff. Who knows? Nobody on this forum by the looks of it, so I've taken the punt and will try to rectify that.
lw395
Well-known member
I look forwards to hearing how it goes.
Just a shame about the 0.1 knot resolution.
The biggest use for a speed log is looking for changes due to sail trim, a log that goes from 6.0 to 6.1 knots could be telling you about a significant increase, or it could just mean it's flipped over from 6.049 to 6.051
I want to see numbers going 6.04, 6.05, 6.06 etc as the speed builds, although the actual speed will always only be 'about six' as the real accuracy is not to be taken seriously.
It's about seeing the little changes, or sometimes stoppng the wishful thinking imagining that pulling the sheet in has made you go faster.
Just a shame about the 0.1 knot resolution.
The biggest use for a speed log is looking for changes due to sail trim, a log that goes from 6.0 to 6.1 knots could be telling you about a significant increase, or it could just mean it's flipped over from 6.049 to 6.051
I want to see numbers going 6.04, 6.05, 6.06 etc as the speed builds, although the actual speed will always only be 'about six' as the real accuracy is not to be taken seriously.
It's about seeing the little changes, or sometimes stoppng the wishful thinking imagining that pulling the sheet in has made you go faster.
richlear
Member
I installed one on my Hunter Pilot 27 about 6 weeks ago and have been very pleased with it. Installation was easy (I paid a professional!!) and it has just done what it says on the tin since then. Calibration is easy using the interface box. Would definitely recommend.
Rich
Rich
adamlang
Member
Would it be easy to wire into the Raymarine ST60 instruments, or SL70C chart plotter?
My main interest would be in the true wind calculations that I think are based on the log speed. Does anyone know whether that works on nmea log speed or if it's just a seatalk thing?
Thanks.
My main interest would be in the true wind calculations that I think are based on the log speed. Does anyone know whether that works on nmea log speed or if it's just a seatalk thing?
Thanks.
cpedw
Well-known member
To get true wind on the ST60 wind display then boat speed is needed on Seatalk.
I think the most useful way to achieve that would be to convert the NMEA output to log-type pulses and feed those into the ST60 log display, as discussed here. One snag is that uses the GPS speed sentence RMC but NASA outputs VHW. As Nigel Mercier showed, it's possible to "roll your own" so it shouldn't be hard to make a converter using VHW from a NASA log. I was thinking of doing that myself if there's positive feedback for the NASA log.
Derek
oldmanofthehills
Well-known member
All hull mounted logs will be affected by weed and barnacle build up on adjacent hull and on unit itself, so none will be much good for navigation over any distance unless continually recalibrated. I adjust gain several times a year by comparing gps with log in still non tidal harbours or lagoons. The only advantage of the new one is that it cant be fouled by twigs or seaweed or broken by boat lifts. If I needed a new one it might be worth extra cost if it could interface directly with my TackTick but I don't and it cant.
tean
New member
My Raymarine autopilot has an NMEA input and outputs Seatalk, which your ST60 wind instrument could use. Perhaps your SL70 can do the same?
tean
New member
Well it's arrived. Nasa seem to have upped the quality of their packaging.
photodog
Lord High Commander of Upper Broughton and Gunthor
tean
New member
Unfortunately I haven't had time to dry the boat out and fit it yet. I currently have an Echopilot paddle wheel job and need to enlarge the hole to take the new transducer. Might get it done next month.
Blue Sunray
Well-known member
:encouragement: I too look forward to the report in due course.
tean
New member
Well I'm afraid circumstances conspired to prevent me getting the EM log fitted last year before winter lay up, but it's fitted now and I can report that it does indeed work.
This morning I moved the boat from its lay-up creek to its mooring which is only about half a mile but the log did pretty much exactly as you'd expect. It is very sensitive at low speeds, giving good readings below 0.25 knots that would hardly get a paddle wheel moving, but even in completely still water it rarely seems to settle to zero, giving random readings of up to about 0.08 knots. I only went up to about 4.5 knots as I had a small RIB tied alongside but the log seemed to track the GPS speed to within about 0.2 knots for most of the time in tideless water.
So very happy so far. Let's see how it fares as the marine beasties start to cling to it.
Rather less happy with the re-vamped YBW forum. Very slow and clunky on my browser.
This morning I moved the boat from its lay-up creek to its mooring which is only about half a mile but the log did pretty much exactly as you'd expect. It is very sensitive at low speeds, giving good readings below 0.25 knots that would hardly get a paddle wheel moving, but even in completely still water it rarely seems to settle to zero, giving random readings of up to about 0.08 knots. I only went up to about 4.5 knots as I had a small RIB tied alongside but the log seemed to track the GPS speed to within about 0.2 knots for most of the time in tideless water.
So very happy so far. Let's see how it fares as the marine beasties start to cling to it.
Rather less happy with the re-vamped YBW forum. Very slow and clunky on my browser.
tean
New member
Having just glanced through some recent posts on this forum, just in case anyone is feeling offended that I have been out boating when we're supposed to be in virus lockdown, I should perhaps say that I am very fortunate to live on a remote Scottish Island and go boating from the pier at the bottom of my garden, so no dodgy unnecessary travelling, no meeting other boats on the water, no sending "the wrong message" to the general public, and no hanging around crowded slipways were involved in the making of my previous post.