Steer by Compass or GPS

Tinman · 03-11-2007, 01:51 PM

What do you guys use to steer a course, the compass or the GPS? I usually pull up the destination waypoint on the GPS, and note the magnetic course. Then I use the compass to follow this course to my destination.

When I talk to other Ifishers on the radio, I've noticed they don't seem to be using compass courses. For example, before heading home from the tuna grounds, I've asked others to confirm the magnetic course that my GPS is reading. But often I get a confused response when I speak of magnetic courses.

Do you guys steer directly by following the GPS arrow or using the cross-track function? What are the pros and cons of doing this vs using a magnetic compass heading. Thanks

Nalu · 03-11-2007, 02:17 PM

Tinman-- For me it's a combination. I have all my headings for coming across the bar in a notepad, and I look between my GPS and Compass when I come across. Magnetic headings from each buoy to the hole, as well as magnetic headings taken each time I leave a new port.

Once actually on the water, I note the general magnetic heading I am taking, but the reality is that GPS takes over from there. With my GPS connected into my autopilot, I don't really steer much at all when travelling between port and halibut or tuna desitinations and likewise upon return.

You bring up a good point though, hopefully everyone knows their magnetic headings to get home when they are offshore. Solar flares, or other things can wreak havoc with GPS Sats. Fortunately I also have a fluxgate compass with my AP, so even if my GPS is down I can lock into a compass heading and it will keep me on that heading.

backlash442 · 03-11-2007, 02:32 PM

I always use a compass heading to steer by and look at the gps to make sure I'm going the right direction (no autopilot) and make adjustments as necessary. Compass is mounted directly in front of the steering wheel so easy to follow vs the gps which was not. Friends boats are the same way but I guess everyone can mount in different locations. This is just what I was/am used to.

You should never rely on the gps to get you back home in case it goes down. Best to have charts on board and constantly think about where you are in relationship to home and the heading you'd need to take to get there. It's ok to be off a few degrees in the day time but it's a very different situation when you are running back in at night.

BTW autopilot is well worth the cost.

Maverick Maxcat · 03-11-2007, 02:37 PM

the autopilot does the steering 99% of the time, both running and trolling. When steering by hand I use wind/wave direction, sun position, etc for general direction. It saves looking at instraments too often. I use the digital readout on the gps for most heading checks, with a glance at the magnetic compass as backup. When running after dark or in fog I use the chartplotter and radar extensively.

Nordic Sun · 03-11-2007, 02:42 PM

If you can steer better than + or - 5 degrees on a 2' and 4' ocean using your compass you are doing very well.

To do better than that use your GPS.

To do better than that use your TR-1 Gladiator it will hold + or -1 degree.

Anyone who says that they can steer better than that, using a compass, is blowing smoke up your bilge, and I will bet big bucks to prove it!

Bob

bajadan2000 · 03-11-2007, 02:49 PM

Same as all the above, even though I have a large, easy to ready compass, most of the time I use GPS waypoints and set the autopilot.

When a crew member is running the boat, I do not let them run on autopilot, I make them use a compass heading. For safety reasons, I try to let everyone on board know the compass heading back to port from our fishing spot.

Tower Todd · 03-11-2007, 06:13 PM

There was no way last season I could steer an accurate course with compass alone and the rough days we had. This year I bought much better compass with much better dampening and bigger easier to read. Will make things much better. Taking a ride with the compass adjuster soon to get everything right.

Tower Todd

Metal Manipulator · 03-11-2007, 06:35 PM

I do not have Auto pilot so I set my course on the gps, and use the road function to keep course, as it helps me keep a straighter line. I always double that with the compass so that I can return on dead reconing if the electronics fail. My first trip to the Rock pile was by compas only. I was realy happy to see the whistler in front of yaquina Bay.

backlash442 · 03-11-2007, 07:34 PM

Odin, I've never run exclusively with just a compass so I can't say how far off I'd be coming home. Typically though, once we have the right heading don't need to monitor the gps that much during the day. Night is a totally different story.

As for going back in 2' and 4' I guess it would depend on which direction you are heading. Into the waves it would definelty be harder to maintain your heading w/out an autopilot. Running downhill or quartering a piece of cake. Some boats just ride better than others.

No blowing smoke up your bilge either.

BigWaterBigFish · 03-12-2007, 08:42 AM

The "TRUE" lost art ... Navigation.
I am about 1/2 though the Advance Coastal Navigation class taught by the local USCG Auxiliary Flotilla - - - was pretty confident about my ability to pilot a boat, not that I have doubts about the past, but feel so much better about the realities in future trips, especially if things go wrong.
This post raises a real world issue - we have lot of us that go out because our pocketbook and interest has got us to purchase GPS and the like, but if all that fails - do we have the skill and training, the understanding of set, drift, tides and dead reckoning, variance and deviation adjustment to bring the boat and those with us (who trust us) back in to port.
Spent three hours last night with a chart, plotting tools, caculator and pencil with BIG eraser trying to do a story problem where you're bringing the boat into a bay and every 30 minutes you are taking lines of position that reflect severe currents, question is what course do you steer, adjusting for the compass issues and the current factors ... whew, I finally got a answer that was "close" but I went through some asprin and head pounding to get it.

fyshndad · 03-12-2007, 09:20 AM

I learned to run on a compass only, back before loran was readily available and even after Loran C came out making it easier we still relied on the compass

I used the GPS but only to verify that I am on course

This year may be different because I now have a large screen chartplotter GPS and I will use it more than I used the handheld GPS

id. painter · 03-12-2007, 01:04 PM

Compass is great .Being able to use one could be crucial.
GPS is better.
id. p.

KeyWest · 03-13-2007, 04:05 PM

I don't know that I steer the boat any more. It's always on auto-pilot and if I want to adjust the heading I turn the heading knob. So not certain - is that by compass or GPS? I guess it's by compass because I'm adjusting the heading. But it could be by GPS because I watch the anticipated track line (the gps projects a line out in front of the boat) and adjust the heading based upon that.

I do run in manual (no auto-pilot) mode while doing white water work across the bar - but that's about it.

Nalu · 03-13-2007, 05:05 PM

Quote:

Originally Posted by KeyWest

I don't know that I steer the boat any more. It's always on auto-pilot and if I want to adjust the heading I turn the heading knob. So not certain - is that by compass or GPS? I guess it's by compass because I'm adjusting the heading. But it could be by GPS because I watch the anticipated track line (the gps projects a line out in front of the boat) and adjust the heading based upon that.

I do run in manual (no auto-pilot) mode while doing white water work across the bar - but that's about it.

You turn a knob, I push a button or correct by the helm. I can't imagine the long runs offshore and back without an AP. Hands down one of the best pieces of equipment on the boat. Straighter course, auto correction, less fatigue.....

Running just using the compass in the fog I would look like a drunken sailor.

KeyWest · 03-13-2007, 05:16 PM

Quote:

Originally Posted by Nalu

You turn a knob, I push a button or correct by the helm. I can't imagine the long runs offshore and back without an AP. Hands down one of the best pieces of equipment on the boat. Straighter course, auto correction, less fatigue.....

Running just using the compass in the fog I would look like a drunken sailor.

I know what you mean. I swapped out a Raymarine for a TR1 last summer and sent the Raymarine to a friend on the east coast. I have been trying to get him to buy an AP for years. Well, he installed the Raymarine and ran offshore one day and called when he got back in saying "I can't imagine how I ever did this without an AP". In Savannah - its 80 miles to the gulf stream. Imagine running that far every trip without an AP!!!

Gloucester · 03-13-2007, 08:05 PM

Great post. Some other things to remember about the compass and the good it can do. This is what we see and may ask on the Coast Guard side.

Scenario 1. You head out of DB for the Tuna Grounds. 15 miles out you lose all power, of course it's foggy, but the cell phone works. You get through to the Station and we ask for your position. No GPS, no hand held, no power. First question we will ask, do you know how fast you were going, about how long were you going, and what was your compass course. I bet ya, we'll find you.! You might even have GPS on your phone! Don't forget to check first, I tried this once while using our work phone, talking to the Group who was talking to the Helicopter. I was up North somewhere on the beach. They needed a position and I had to hang up and go over to the GPS function then call them back. I was not 15 miles offshore though.

Scenario 2. You are offshore and off in the distance you see a flare go up. Immediately you call the Coast Guard. After we get your position, we are going to ask for a compass reading. Placing your bow on where you saw the flare and sounding off. Now we have a starting point from your position and a compass line to follow. Somewhere on that line we hope to find what you saw.

Scenario 3. You are a resident on the fishing grounds every year, we get the phone call that you have not returned from your fishing trip. Some questions we may ask the caller. Is there a float plan. On the float plan is there standard compass course's to the fishing grounds, just things to think about.

I love our NAV Plotter and GPS, but there is no doubt that as I watch the screen my next glance is at the compass.

Also be weary of what you put next to the compass. Metal, binoc's these things will throw your compass off. If you have a lot of electronics, you could get EMI(electronic magnetic interference). Check your headings on the ranges at Depoe Bay and Yaquina Bay. Those ranges are charted, printed on the charts. Line them up and see how your magnetic compass reads compared to what is printed.

cs

seajay · 03-13-2007, 09:50 PM

I hate to tell you how many years it has been since I was a B-52 Navigator, but even though I am not still flying, the B-52 still is and the techniques I used (compass, loran, inertial platforms, celestial navigation, etc) have pretty much been replaced. (In fact they no longer teach celestial navigation)

Yes, I have a compass and refer to it, but as long as I am locked onto the gps system, I will use the accurate, updated information that is available. I will also use the radar and visual information. The compass is a tool and will be used, but as long as the others are available, it will not be the primary tool.

In the old days we used compass headings, depths, loran, and radio to help us get around in the fog, darkness, and inclement conditions. Today I feel much more confident and sometimes a lot less crazy with utilizing the new equipment that is available to us.