GPS Units 2020

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Andrew
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GPS Units 2020

Post by Andrew »

Hi All,

It would be good to find out what GPS units everyone is using for Navigation,
I went for the portable type on a budget, but there are other options / chartplotters out there these days, what do you recommend?

My story: Returned from a trip from Hinchinbrook island , 5 days 4 nights (24th to 28th Sept 2020). had never sailed it before, its a huge semi-wilderness area. It made me realize that good GPS navigation gear is probably well worth it for cruises into unfamilar remote tidal regions.

I used my Garmin GPSmap64sx handheld unit for the trip (use them for work) but it's not ideal. It's a hiking GPS with topographic base maps for land use, the basemap just shows blue for the sea. It can mark a point in the ocean where i wanted to go then it would show data like the ETA, speed made good, time to travel on the compass page. It's not really suitable for serious marine Navigation. Also It will sink like a stone, runs on 2 x AA batteries.

So on return was motivated and bought a Garmin GPSmap78sc,
Its a marine portable GPS with charts/ chartplotter.

The color charts cover ALL of Australia and NZ in fine detail, every navigation bouy or lighthouse, all the ports and anchorages, intertidal zones - sandbanks, undersea cables and pipes, even pens in Marinas are shown. Has bottom contours and spot depth soundings. . Also bought the mounting bracket, . It can go into a travel bag and be used on any boat anywhere. runs on 2 AA batterys, floats and water resistant. It was considerably cheaper (on special, $360) than most of the big screen fixed and cabled chartplotters out there that i looked at.

Always carry conventional Marine paper charts aboard too, old fashioned but easy to see the overall picture at a glance (the GPS has a small screen and mostly tells you whats immediately around you)
Andrew

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Peter T
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Re: GPS Units 2020

Post by Peter T »

I have still got my old hand held Garmin GPS 45. Was told that it's out of date and wouldn't work anymore. Cleaned up the battery connectors and fitted new batteries. It had been years without use and had lost all its data. Turned it on and left it sitting in the middle of my back yard for a couple of hours and guess what, Woo Hoo, found heaps of satellites and it's working fine. Now all I need to do is make a fitting to bolt to the boat to mount the holding frame and wire it up and away we go. Only problem is the date. It's pre 2000.
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Andrew
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Re: GPS Units 2020

Post by Andrew »

Good that the old GPS45 is still going strong Peter, i used my GPSmap76 for decades, but finally the screen has a black patch (with reverse contrast) growing in the middle of it, so hard to read it now.

That's a more economical way to go David, and the barometric altimeter and inbuilt compass probably aren't vital features when moving at sealevel.

(Some of the fishfinders ive been looking at also got chartplotting, but now halfway down the two separate units route now.. )

Cheers
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Ozzie
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Re: GPS Units 2020

Post by Ozzie »

Good topic guys. I just thought I would add for those of us who don’t need to do the complex things that a proper marine GPS will do that it’s also possible to use your car GPS unit or maybe an old one you have since superseded for limited use on the water. I have an ancient Garmin Nuvi that I have used for this purpose. At least this will give you a fairly accurate speed albeit in kilometres per hour which you can have a small conversation scale stuck nearby. But as I have never connected up my paddle wheel speed log it’s not half bad for this purpose.

Also we have this when on the lake at night after a funny or perhaps not so funny incident occurred one night after we had been fishing and we’re heading on a long run back to the mooring. I had let the fuel tank get a bit low, but had a jerrycan stored for backup purposes so we stopped the boat turned the engine off and refuelled then headed on our way taking close observation of the navigation lights that we were familiar with in the area. You can see where I’m going with this story, suddenly something seemed wrong with the navigation lights that should’ve been ahead of us were not there. A quick review of the Garman indicated we were heading totally in the wrong direction.

It’s unlikely I guess, but if you are navigating in crook visibility with rain, drizzle, fog, maybe your just tired, whatever even in familiar waters it is sometimes not hard to get disoriented. If the circumstances arrive I suggest everyone try testing yourself one night in familiar waters, close your eyes get your crew to spin your boat around in circles a bit then open your eyes and try to continue without assistance from the crew.. fun exercise. :roll: Yep, you could also use your phone for this but it’s surprising how many have a superseded car GPS floating around somewhere that you could leave on the boat. Also many phones need mobile tower connection to work as a gps and chew up lots of power in that function. Again i’m not suggesting in any way replacing dedicated GPS units for those requiring important navigation and depths etc, but this could be of use to someone else.

Also you have to accept of course that such devices are not marine grade and therefore not waterproof but it’s easy to solve this problem by simply sticking them in a good clear plastic bag or container which can in turn be stuck to the bulkhead with double sided tape or something similar. Poverty central...over and out

https://www.thegpsstore.com/Can-I-Use-a ... -Boat.aspx

Here’s an article I just googled up that discusses it
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Re: GPS Units 2020

Post by Ozzie »

Yep, I know most of the shoals in various bays in LM after 65 years, but I need to know which bay I’m in first :oops:

Phones will give some marine info I believe with correct app , I would not rely on phone towers. I have had a fish finder/sounder brand new for years . One day I’ll get it out of the box.
Ozzie
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Enola - “Helen said that it’s only land sickness."
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Andrew
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Re: GPS Units 2020

Post by Andrew »

Wow that's crazy wave heights David, lucky to survive that saga, (I was going to use my altimeter for mountain hikes!)

I'm going to feel allot safer with the new marine charted GPS, (plus GPS enabled fishfinder..croc finder?) too many coral reefs, mud and sandbanks with sizeable tides - etc around here. and planning to venture into unknown waters soon for longer time periods. Ozzy Im using mobile phone navigation too, but since going to the "far side" of high continental Islands a few times and loosing signal/reliable navigation... and also worried about my mobile getting salt water stuffed-up forever,

In the process of fitting the electronic gear. Their mounts are designed to go on a horizontal surface. so Building a 7" wide seat/mini bridgedeck in 3/4" pine across the companionway doorway, and mounting the electronic units on it, each side (there's a 2-3" space between doorway and the cockpit sides , they snugly fit into) i was worried that jib sheets etc would soon wipe them out on the cockpit bench fronts. the cabin top is worse, have to clamber over it under the bimini would knock them off) Where they are now, the 2 units can tilt at about 40deg and swivel a bit for different tacks, to get best view angle) Where they are located is also fairly dry and out of the spray line. They can be removed and stowed inside if needed.

got 12v main battery power onto the F'finder and the GPS page works..(It's a Garmin Striker +4 with GPS, total cost was $200 with bcf club membership, it has no internal batteries but connects to 12v with a cable) has its own bathymetric chart making capability as it scans the seafloor and stores waypoints for return navigation, but no marine charts. Anyway double-redundancy with 2 gps units aboard. The GPSmap78cs runs on 2 AA batteries so will go even if the main electrical system is down.

The GPS F'finder's transducer is transom mount design. So going to try that location first, just running the wire up the cockpit drain and along the floor side under the grating mat for now/ testing times. If it works will leave it, otherwise there's several internal locations (but they would need oil filled housings, far more complex) (ps found an old cable entry hole in the transom higher up, so may use that if it works ok).

There is a square hole in the cabin end , where the ancient fishfinder lived. it may make a good compass location. Interesting the idea of a lit handbearing compass with a wall mount,,
Last edited by Andrew on Wed Oct 07, 2020 8:42 pm, edited 1 time in total.
Andrew

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Re: GPS Units 2020

Post by Andrew »

I used my car GPS for awhile Ozzie, it could do rough navigation set to off road mode.

Made some progress on the ff/gps - got the transducer transom mounted and the demo mode going, so all the sounders pages had something on them. There are still screws and holes etc from an old transducer. so put it next to that, its about 30 cm out from the centerline/keel-line on the opposite side to the outboard. The boarding ladder is just outside the transducer, and the rudder swing doesn't knock it.

Never can be too careful David, thanks for info on compass (getting thread drift happening...is it time for a compass only new thread?)

(ps: my ff/gps also has a compass readout on the gps map page...)
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Re: GPS Units 2020

Post by Andrew »

The technology must be surging in leaps and bounds, but this doesnt necessarily make old tech obsolete. Best to have old tech backup aboard incase some or all of electronics fail. "if it works ok, leave it" is my motto.

On Tarzali Bill's utube videos of "Secret Chords" qld coast voyage, spotted GPS chartplotter/fish finder mounted on a stainless swing arm high up in the companionway door. Its all in one unit. This looks like a very good setup for cruising. It can be swung in and monitored from the cabin as well.
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Re: GPS Units 2020

Post by Andrew »

Thanks for the prompt David, was starting to get a bit slack in my old age and the electronics age! started improving my ,"ye olde" coastal nav kit as you've listed. Finally dug up the old brass dividers and roller parallel rule (from NSW coastal cruising days, 1988)..looking for Jeff Togills (1980s) coastal nav book next.

Learnt Navigation in the 1970's and 1980's, getting a bit rusty

Plan is to test the new navigation equipment out in local waters first, before any bigger ventures
Last edited by Andrew on Wed Oct 14, 2020 8:00 am, edited 1 time in total.
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Re: GPS Units 2020

Post by Andrew »

I agree David, several backup nav systems required for big trips outside our local well known sailing grounds.

Rarely GPS signals get fuzzed during wars, so its about 30m out..

Sorry i edited my last post, re the original "transit" satnav system of the 1980's. We are very fortunate with modern GPS. 3m accurate, 100% coverage and cheap. (The transit satnav in 1983 cost that owner $6000 then, about the cost of a fully fledged coastal keel yacht now,like a Top Hat to H28, ajusted for inflation!) (My whole budget to deep sea crew for 5 months in 1983 was way less than that!). The old sat nav had blind periods lasting hours, and satellites whizzed by quickly in LEO. also accuraccy was 50 -100m..good then. The skippers taught me how to take sextant sights, "sun run noon set" method, fix accuracy lucky to be several nautical miles,, but good enough mid ocean. Had a go with star sights too, (but much harder), the good olde days

expensive satnav was totally superceded by GPS in 90s ..(could this happen to present GPS in future?)
Andrew

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