Hull speed vs. wind speed

[nies]

Well its 28 below this a.m., just burned my chip log for heat , the wood chairs next.....oh for warm breezes.....Phil

[kchunk]

I really don't know if I want to continue with this...

Maybe my chart plotter has a speed transducer plugged in. You know, the little paddle wheel that always gets jammed up with barnacles or zebra muscles or that little twig of seaweed. That thing is about as accurate as a chip log.

I suppose you can look at boat speed from two different perspectives. When I used to crew on a Swan in a local regatta here, just off of Daytona Beach, speed through the water was of utmost importance. Slightest trim adjustments would yield +/- the smallest fractions of a knot and our captain wanted every one of those fractions in our favor. Now, me and Com-Pac, I'm not as interested in how fast I'm going through the water as opposed to how fast am heading toward my destination...my speed OVER water (or ground if you will).

Anyway Shawn, you're right the GPS alone will not give water speed. So, what does that do to our algebra lesson from earlier? We have speed accurately measured at 5 kts using our chip log and we know we have a distance of 100 nautical miles to traverse to reach our destination; can we assume with any accuracy when we'll arrive using either Time = Distance / Rate or our slide rule or spin wheel machine? I suppose you could just guess at the current and come pretty close, but that negates any accuracy no matter the measuring device.

The chart plotter computes this automatically and updates it every second or so.

I'm certainly not trying to start, nor am I interested in, a pissing contest. Mariners, like most people, will always have differing opinions on the best way to get something done. I'm not trying to convince anyone that my way is best...I really don't care. But I guess what I am trying to say is just because it works for you (whomever), doesn't necessarily mean you've found the best way of doing it (whatever). Don't be so closed minded. And be careful with the influence you may wield. Some here may put a lot of value in the experienced opinions of others.

For what it's worth...




Oh, and Bob, Mr. Merv Grazinski of Oklahoma City was his name. Thanks for the Stella reference. A little Google and a little snopes.com (love that sight) convinced me it's urban legend. Can't believe everything you read I guess...

And Newt, yes, we've gone way off topic AGAIN. Imagine that...a topic on the CPYOA that strayed off topic. That never happens here 

[newt]

Grog to ya Greg. May your keys passagemaking be full of  warm easterlies and lacking in clocking northen'ers

[nies]

O.K., I give up .....I'm going to buy a hand held GPS just to play with, why I would need one on a lake of 5000 acres I don't know, just don't tell the wife I don't need one...........any suggestions on brand, etc?..........Phil

[botelerr]

The need for a chart plotter depends where you sail. I sail on the Mississippi most of the time on the CP19, don't even have a depth guage, probably should.. but once a year I sail off the coast on Maine on a 30 Sea Fairer,, we use detailed charts, a plotter and a compass,, the rock shelves are frequent and un-forgiving.. and yes, last year we still hit one..Rob

[Craig Weis]

Go here

http://www.usps.org/localusps/door/

and ask Marcus about which ones work well. He's the man.

skip.

[HenryC]

Upon rereading my earlier posts on this topic, I can see how I may be coming across a bit shrill and opinionated on the tired old debate of modern vs traditional navigation.  I apologize, and I am ready to concede that it is perfectly right and proper for any skipper to take advantage of any technology at his disposal if it makes his sailing safer or more convenient.  

Your chilling picture of a "norther" off the port bow brings back to mind unpleasant memories of trying to deal with flogging sails, charts and papers blowing about, and a panicky crew-- simultaneously.  Of course, having all your navigational information instantly available at your fingertips in an easily visualizable form is priceless.  Only a fool could fail to see the advantage in that.

My concern is how over-reliance on technology can also lead to over-confidence, and to neglect of basic skills.  You don't need to be a celestial navigator, but you should know the stars rise in the east. And technology also requires a heavy investment in practice and training.  It only becomes second-nature after you've used it for a while.

Still, I suppose when the compass and chart were introduced, the old-timers complained about how the old skills were disappearing...

[tmolik]

To all com-pac sailors..
The only real important issue is not speed thru the water but speed over ground.  Long ago (1978), with my Catalina 27, I went out the Ft. Lauderdale cut a couple of miles, sailed all day, I think north, when done, I turned directly back in to return, no angles, but straight in. Not a lot of miles covered, but a lot of "thru the water miles".
Now, after many years sailing a Peason 35 on Lakes Erie and Michigan, I thrive now to keep it simple, (KISS) with my 2001 Suncat.  No battery to keep charged, no thu the hull fittings, a trailer to allow me to go anywhere, etc.,etc.  I use a Garmin 276C mounted on a small transportable  board for chart plotter, speed over the ground, tide predictor, etc. It's a great small boat tool. Naturally I use paper charts.  Also I have two hand held compasses for verification, plus a hand held West Marine depth sounder.  Unless you are a blue water sailor, or a blue water pretender, you need to keep it simple on a small sailboat with limited speed and distance traveled in a day's sailing. 
I have a Plath and Weems sextant used once to earn navigator rating from USPS and I never used it on the water, a big expensive  overkill!!  Someday I may sell it. I thought of installing Lazy Jacks, but that would be contrary to the KISS principle. I could go on, but you know, KISS.
   
 

[Salty19]

I'm not a blue water sailor, but if I did decide to do it someday, I would definitely learn manual navigation using sextant and charts.  And would of course bring along a GPS and also look into other electronics (like the chartplotter).  I have good navigation skills with topo maps and compass-and use this first when surveying my land.   I bring along a GPS mainly to know if I get lost, I'll have my campsite/truck marked as a waypoint.  It will get me home.  With that said, if it failed I would still be able to retace my tracks using a good old fashioned compass, maps and notes.  Albeit at the expense of time.

I think of electronics as convenience features only.  And I'm kind of a gadget guy. Anything can happen to them...they could get wet, the battery could short out, there could be a wiring problem or just a flaky power connector.  Or they could give you the wrong data (unlikely).

If you rely on electronics and they fail and there is no knowledge manually how to navigate, you're screwed. 
In most all situations they are great to have.  But if they fail you need a backup plan.

[Shawn]

"Now, me and Com-Pac, I'm not as interested in how fast I'm going through the water as opposed to how fast am heading toward my destination...my speed OVER water (or ground if you will).

This thread is about hull speed, something a GPS alone can't give you. This is a common error I have seen in many threads, glad you know the difference.

"The chart plotter computes this automatically and updates it every second or so."

I have a Garmin 478 chartplotter. When I want to know my hullspeed I use my knotstick.

Shawn

[CaptRon28]

I got a kick out of reading many of the above responses. I've been sailing for a long time with numerous ocean deliveries on much larger boats. Any electronic devices you've got on the boat are just tools which can help you at times. Can you do with out them, -sure! Should you know what to do when they break down - of course! Would Columbus have liked a chart plotter with an up-to-date electronic chart on the Santa Maria. You bet he would! And remember that your vhf is an electronic tool too. I wouldn't leave the dock with out it. You shouldn't either.

And boat speed vs ground speed vs wind speed. What's the big commotion about? All three are important numbers which you should know at most times. You can't really use ground speed to measure and improve the boats sailing performace day after day. It's how fast you are going thru the WATER that matters then. Same for boat speed. Your speed in the water is not that helpfull in finding out when you will get to the next waypoint or destinaton. And wind speed has very little in common with either of the above. Translating that to boat speed depends on the boat, the condition of the sails, the wind angle, and the ability of the skipper and crew, etc. There are sailboats out there which will go over 3 times faster than wind speed. Like 30+ knots in 10! And there are boats which will do maybe 2 knots in 10.

Ron M  - USCG Master's, 100 tons, ocean rated
Telstar 28, looking for a Horizon Cat