Electronic Navigation Lesson Needed

[kiwa]

I have been off the cruising scene for a few years.I have offshore experience , my tools were an NC77 calculator and sextant with full horizon mirror and applicable charts.( Till I got Sat Nav just before I sold the boat - thought that was pretty amazing technology ) Coastal nav was a handbearing compass , depth sounder , sumlog , paralell rule etc.
I had SSB radio and liferaft (10 fixed channels )
Im looking at getting back into cruising ( buying a boat )and am quite mind boggled by what is on ( and sometimes not on ) yachts and what it does and what is worth having and what is not.
IE Chart plotter - does this replace the need for paper charts totally, How expensive is it to get charts for it ? Are they readily available.
SSB - able to send and recieve email (sounds pretty great - is it as simple as that??
Laptop computers- some boats have them with them with some sort of navigational programme ??
So in short - what is the essential nav requirements I will have to go out and purchase if they are not with the boat I buy.
I intend to go extended offshore
Any advise gratefully accepted - Thanks

[O.C.Diver]

Originally Posted by kiwa

I have been off the cruising scene for a few years.I have offshore experience , my tools were an NC77 calculator and sextant with full horizon mirror and applicable charts.( Till I got Sat Nav just before I sold the boat - thought that was pretty amazing technology ) Coastal nav was a handbearing compass , depth sounder , sumlog , paralell rule etc.
I had SSB radio and liferaft (10 fixed channels )
Im looking at getting back into cruising ( buying a boat )and am quite mind boggled by what is on ( and sometimes not on ) yachts and what it does and what is worth having and what is not.
IE Chart plotter - does this replace the need for paper charts totally, How expensive is it to get charts for it ? Are they readily available.
SSB - able to send and recieve email (sounds pretty great - is it as simple as that??
Laptop computers- some boats have them with them with some sort of navigational programme ??
So in short - what is the essential nav requirements I will have to go out and purchase if they are not with the boat I buy.
I intend to go extended offshore
Any advise gratefully accepted - Thanks

Paper charts and 2 GPSs at a minimum.

IMO, redundancy is the key. A simple battery operated hand held GPS will allow you to take your position and plot it on a paper chart. Additionally, you can enter a position off of your paper chart into the GPS and it will plot a course to that position (bearing to target), give you distance to that target, show your speed and actual course, and give you correction factor (cross track error) to correct your course. And that's about 10% of what a hand held GPS in the $150 to $300 range can do.

Now for me, I prefer a 10" diameter screen chart plotter (moving map) that holds my position in the center of the map, can reduce the scale to where the width of my screen is .125 miles across, will do split screen to show moving map & the data screen for course heading etcetera, and will do radar overlay where my radar is displayed on top of my moving map. The radar overlay confirms that the target you see up ahead is or isn't the can buoy you are expecting because it is or isn't next to the symbol on the chart. All this costs a couple dollars more

The key is redundancy. So I have the really nice full featured system and a hand held GPS with paper charts as back up.

Ted

[skipmac]

Hi Kiwa,

Your situation sounds close to mine. Sold my last boat 28 years ago. Navigation offshore was a Plath, HO249 and paper charts. Guess what. That will still work just fine.

If you want to join the 21st Century it's fun and saves a lot of time but I would keep the old tools along as backups. There are those that depend exclusively on electronic charts, I'm not one of them.

How you participate in the new electronics will depend primarily on budget and then on preferences.

Cheapest. Small GPS without electronic charts. Plot lat/lon on paper charts.

Next. Chart plotter/GPS with electronic charts. Can go with handheld units with small screens for a few hundred or built in units for hundreds to thousands.

Top. A multifunction, integrated system with displays in the cockpit and nav station. Will show chart and location with radar overlay, speed/depth/wind, send data to the AP and fix coffee in the morning. Bring your big wallet.

Charts. Not cheap but I think similar to buying a full set of paper charts (ocean, approaches, harbor, etc) for the same area covered by an electronic chart set, typically a $300-$400 per region in the US. I did start adding up the cost of a full set of charts to cruise UK and the med and stopped counting when I hit about $4000.00.

[donradcliffe]

You will want 2 netbook computers, plus the OpenCPN nav program--see the thread on this forum, plus 2 or 3 independent GPS's that will plug into your computers. One of these should be an AIS transponder.

A few paper charts as backup, a pactor unit for email and weather over the SSB, and your trusty sextant and watch if all the electronics pack it in.

[kiwa]

All good advise- starting to get my head around things-
Really seems to have taken the uncertainty out of navigation - which can onlyh be a good thing .
Will definately keep the sextant and paper charts as a back up though as you said - anybody ever thought of the chaos if someone decides in the interest of national saftey ( or some other world event ) they are swithching off the satalites!!!!

[O.C.Diver]

Originally Posted by kiwa

All good advise- starting to get my head around things-
Really seems to have taken the uncertainty out of navigation - which can onlyh be a good thing .
Will definately keep the sextant and paper charts as a back up though as you said - anybody ever thought of the chaos if someone decides in the interest of national saftey ( or some other world event ) they are swithching off the satalites!!!!

Actually, it is my understanding that the US government has a protocol to induce an error factor so that the enemy's gps guided weapons wouldn't hit their target. Since we know what the error factor would be, we could adjust our weapons to be accurate. My understanding was that an airplane would still be able to find the airport but not the runway with this error.

Ted