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AIS and Knot Meter Requirement

D

Darren

Enough to be safely dange
I was just looking threw the safety requirements and came across section 3.7 AIS. All boats shall have an AIS Transponder. Maybe I'm miss understanding or they are using the term wrong but I though transponders were only for larger boats, and were rather expensive. Did they mean receiver so you can see incoming traffic or did they really mean transponder so other can see you. The effective date is 2024 so maybe some newer devices will be on the market by then.

Also does GPS count as a knot meter?
 
a knot meter is a knot meter, eg a instrument for measuring speed through the water.
It is there as a requirement so that (amongst other things) the skipper has 1/2 of the means to maintain a dead reckoning track/position.
No, GPS doesn't meet the requirement.
But if you're Skip apparently an orange and a stop watch will do. ;)
 
DaveH said:
a knot meter is a knot meter, eg a instrument for measuring speed through the water.
It is there as a requirement so that (amongst other things) the skipper has 1/2 of the means to maintain a dead reckoning track/position.
No, GPS doesn't meet the requirement.
But if you're Skip apparently an orange and a stop watch will do. ;)
Click to expand...

I agree with the above. This has been covered before on my thread. What I say is unofficial, my opinion only, and at times unreliable. When I raced WILDFLOWER in a Pac Cup, head inspector Chuck Hawley came aboard at Santa Cruz Harbor with his inspection list. When he got to the knot meter requirement, I explained I built WF purposely with no thru-hull fittings and was not about to drill a hole in the hull for a 50 cent plastic paddle wheel. Chuck said, "yes, I agree, what is your point?"

I pulled out my knot meter, which was a large Navel orange written on it with black felt tip the the speed formula for measuring the time an orange peel passes bow to stern. Chuck agreed, and said he'd learned that formula as a kid also. I passed the knot meter requirement and we shared the orange.

This does not mean an SSS inspector will agree in 2023. But that was my experience and precedent at that time, 20 years ago.
 
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So you know, in the 1978 SHTP on WILDFLOWER I had no electronics or instruments but a compass and Walker log. I kept a log book updated every 4 hours with estimated course and speed, as well as celestial fixes and noon positions. After the finish at Hanalei I went back and plotted my Dead Reckoning positions only, not the celestial fixes...By the time I reached the finish, my DR position was 14 miles off. It can be done.

Still unsure of my navigation accuracy, I carried a small AM battery radio. When ~ 300 miles out, I began receiving Hawaiian stations. By rotating the radio (antenna) I assured myself Kauai was dead ahead. Hono off the port bow, and Hilo on the port side.
 
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My boat doesn't have a hole for a paddle wheel. I'd rather not drill a hole for a transducer to check a box. I guess I could have a transducer on a stick. I don't understand why GPS wouldn't count. I understand the point is for dead reckoning navigation but if you have power why not know exactly where you are with GPS. If you don't have power then yeah fruit away.
 
Redundancy is good. Oranges are tasty. If you have a handheld Garmin with plenty of batteries, an inexpensive tablet with a chart plotter installed, and a Standard Horizon radio with AIS and GPS, that all counts toward the requirement, right? No need for a hole in the hull.
 
Oh, gosh! Monday morning at work: But wait! I have something more important to do! Gotta look up arcane words.

knotmeter.jpg
 
That's why I call mine a speedo - is that in there? This is also good for raising the eyebrows of newer sailors (usually followed by an eye roll).
 
There are alternatives to an electronic paddle wheel installed in a hole through the hull. Go back to the 1960s...

The knot stick:
http://www.knotstick.com/

A chip log and a stop watch (similar to Skip's orange, simple to make yourself):
https://www.rmg.co.uk/collections/objects/rmgc-object-42932

If you really want to get fancy, there's the Walker Taffrail Log - though these were mostly used for larger ships traveling at higher speeds.

If you want to get more modern consider a Pitot Tube or Manometer. Pitot tubes are how airplanes sense their speed through the air - about as modern as you can get.
 
It does feel like if the intent for the knotmeter is dead reckoning to provide position that the GPS would provide much more accuracy. Of course if the satellite network goes poof then that's that but to points stated earlier, any floating object and a watch would work.
I'm not trying to be a smartass here, I'm certainly not a good navigator and have mostly used my cell phone's GPS, an app and downloaded NOAA charts. I'd love to be educated, in particular considering what I'm still hoping to accomplish one day. My plan is: have many GPS on board (using different networks), multiple electronic ways to see charts, and large scale paper charts.
 
Hi Philippe - an indirect (or direct) lightning strike to the boat is a more likely issue than the GPS constellation failing. A strike will take out the boat's on-board equipment containing integrated-circuits (IC) chips, at which point you're toast. I do carry a sextant, printed nautical almanac, HO 229, and believe it or not an analog/mechanical wrist watch - no battery inside the watch. I even know how to use it! Add some plotting paper and large scale paper charts, a pencil, straight edge, protractor - and you're good to go.

Perhaps super-old fashioned, but that stuff does help me find out where I am when all the fancy stuff is toast. And I have a Monitor windvane - not that you'd want one of those bolted to the transom of your Class 40! Lightning squalls are no fun, lightning bolts to the water are even worse.
 
Good point! I forgot about the strikes. I do recall recommendations about sticking a battery-powered GPS into the oven (which of course I don't have on my boat). I wonder if an EMP pouch would work just the same.
 
tiger beetle said:
Hi Philippe - an indirect (or direct) lightning strike to the boat is a more likely issue than the GPS constellation failing. A strike will take out the boat's on-board equipment containing integrated-circuits (IC) chips, at which point you're toast. I do carry a sextant, printed nautical almanac, HO 229, and believe it or not an analog/mechanical wrist watch - no battery inside the watch. I even know how to use it! Add some plotting paper and large scale paper charts, a pencil, straight edge, protractor - and you're good to go.

Perhaps super-old fashioned, but that stuff does help me find out where I am when all the fancy stuff is toast. And I have a Monitor windvane - not that you'd want one of those bolted to the transom of your Class 40! Lightning squalls are no fun, lightning bolts to the water are even worse.
Click to expand...

I work with data radios and when lightening strikes it on takes out what isn't grounded. I've had things get struck by lightning and that one thing doesn't work everything is fine. I've heard you can ground the mast by wrapping chain around the upper shrouds and backstay and run the other side into the water. To be clear I'm not saying hoist your anchor chain up the mast. Just wrap it around the base. I guess you could use your anchor chain. Or if you want something else you could run 4awg wire from the shrouds and back stay into the water. The point is getting the lightning to the ocean as fast as possible. It doesn't want to go inside your boat it wants to go to the ocean floor. Another thing you should have is a polyphase on your radio coax. Typically they are grounded to earth. So I guess if you have a metal thru hull near your radio that would work. Or ground it to your mast and then ground the mast over board. There's also lightening protection "fuse" things that we use at our field radio. I'd have to look up what they are called but they work like a transistor. The high current cause an open on the load side and sends the excess current to ground, or sea for our use.
 
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