Hand Bearing Compass

[Inverseyourself]

Probably known already to some/many of you, I just stumbled upon a video featuring a hand bearing compass. Although not cheap, it is a pretty nifty tool to fix your position - fast and reasonably accurately, I suspect significantly more accurately than with your hand held base-plate compass. Is anyone using it and if yes what is your experience with it?

Edited November 28, 2015 by Inverseyourself

[Gcosloy]

Andy,

We'll need a link to see the video.

[Inverseyourself]

Here goes:

[Inverseyourself]

Another one:

https://www.youtube.com/watch?v=JyT4vhiRMs8#t=11

[gyork]

Never used, nor felt the need for one on the water, but suspect slight improvement over orienteering compass alone, or in combination with the deck mount.

short discussion from WM site: http://www.westmarine.com/WestAdvisor/Hand-Bearing-Compasses

[Paul Sylvester]

A step up from the small compass I keep in my pfd. This one looks too large. I have seen and used a prism style sighting compass on the water. At about 60$ it is on the someday list.

[Pintail]

Andy, far be it for me to try to discourage you; but <when> is this going to be of practical use to you? I doubt you would be able to take any sort of bearing with accuracy in anything but a calm sea, for one thing -- and, for another, if you have done your homework before getting on the water, then why should taking accurate bearings be important? Kayaking is of limited range, as a form of transport in daily terms (well, how far can you paddle in a day?), so how accurate is accurate enough? As for bearings needed to avoid collision, a rough bearing is all that is needed by mark-one eyeball, surely?

In other words, it is one thing to navigate on a sailing yacht offering the luxury of a chart table or the flight-deck of an old B707; quite another to try navigation from the precarious perch of a heaving kayak, which (in my opinion) is why navigation (for us) needs to be a practical, abbreviated business. I admire John Huth's encouragement to make ourselves familiar with not getting lost (and, in any case, I have already passed exams in practical and plotting navigation); but us lot are hardly ever out of sight of shore and hence my assertion that our navigation is mostly of the seat-of-the-pants sort -- so why make matters more complicated?

By the way, one should get used to using the term "magnetic" after taking any sort of bearing -- that fellow in the second video did not -- to remind one's self to add or subtract variation when plotting...

Edited November 30, 2015 by Pintail

[Inverseyourself]

All very true. Once the initial fascination with cool gadgets has settled, keep land on your left/right is good enough! Reg. magnetic, maybe the guy in the video computed it without needing to tell any one...maybe he got lost.

[leong]

Andy,

I agree with everything said above by Sir Christopher. He’s our esteemed grammatician, airplane pilot and paddler, Although a hand bearing compass is a cool device, and it's fun to learn how and to use any type of compass for navigational purposes, a low cost GPS does a lot more (as long as it works, that is).

Allow me to plug the one thing that a GPS can do that can't be reliably done any other way (even with all the tricks that John Huth has developed). As we all know one cannot simply point their kayak at a waypoint and expect to get there along a straight direct-line course-over-ground. To stay on this straight line we have the concept of ferry angles (you offset the kayak’s heading by the ferry angle). But, unless you know the kayaks side drift (due to wind, current, waves, etc.) accurately, you can’t compute an accurate ferry angle. Furthermore, conditions vary so the necessary ferry angle varies in accordance.

With a GPS, the whole concept of computing ferry angles becomes moot. Here’s how a GPS works to get you along a straight line to a waypoint:

The GPS knows the kayak’s location and the waypoint’s location in some fixed earth coordinate system. It doesn’t know it’s own orientation (what direction it’s facing or even if it’s pointing backwards or straight down). It also doesn’t know the heading angle of the kayak. But it does know the Course-Over-Ground (COG) that the kayak is moving along as you paddle. If the COG coincides with the direct straight line from your present location to the waypoint, the GPS’s arrow (at least it’s an arrow with my GPS) points to the top of the screen. If the kayak’s COG for this latest update is to the left of the present direct straight line, then the GPS’s arrow points to the right (indicating that you should change your heading to the right), and vice versa. In effect, the GPS knows that the COG is the vector sum of the kayak’s forward speed and whatever is the cross-velocity vector. So, the GPS doesn’t really have any idea of current velocity (I mean water speed and direction) or wind or anything else that’s pushing the kayak. All it really knows is the COG and the latest direct straight line to the waypoint. As long as you keep the arrow pointing to the top of the screen (via heading changes as necessary) you will be following a direct straight line to the waypoint.

From many conversations with NSPN members, I’ve found that most don’t realize that ferry angles don’t come into play when you use a GPS. That is, they think a GPS always keeps your heading pointing to the target. If that were the case, the course over ground to the waypoint would be a curved path whenever there is any side drift. (For constant side drift that curved path is called a pursuit curve.) As shown above, you do follow a direct straight line to the waypoint. So this feature of how a GPS works makes the GPS a really cool gadget. Obviously, a GPS has many other cool features.

-Leon

[NateHanson]

These are a staple of larger boat navigation, and being a sailor before I was a kayaker, I was really keen on having one for kayaking. The "hockey puck" style hand bearing compasses used on sail boats are too big for kayak use, in my opinion, so I was really excited a number of years ago to find a Brunton baseplate compass (now discontinued) that had a lens in the bezel, and works just like the hockey puck style compasses, yet is no larger than a normal baseplate compass. You can easily take bearings to within 1 degree. It was about $100, quite nifty, and I carried it for years. Though I am a bit of a navigation nerd and generally do more navigating than I technically need to do when paddling, I rarely used the sighting function of that expensive compass. The reality is that I navigate differently in a kayak than I do on a keel boat, and a hand-bearing compass isn't really necessary, so I gave up carrying that $100 compass in favor of a $15 baseplate compass a few years ago.

Basically, everything in a kayak is plus/minus 10 degrees, so taking bearings with your bow, or with your baseplate compass is accurate enough. Keelboat navigation is less forgiving, and every degree counts when being 50 feet this way or that way could mean hitting a submerged ledge (where you might then spend the night living at a 45 degree angle). In a kayak, we just paddle to the ledge, and look down to see when we're on top of it.

[NateHanson]

About the GPS discussion, I'm no purist, and GPS has it's place. However, it is indeed quite possible to make a straight-line crossing in thick fog, across unknown currents of varying speed and direction, using only chart and compass . . . and lobster buoys. The lobster buoys are crucial. If they are spaced less than the limit of visibility, you can stay on a perfectly straight bearing and nail your destination every time. I find this much simpler and quicker than GPS, and it keeps my attention on the bigger picture, rather than staring at a tiny screen in my lap.

That said, I'm not nearly as worried about getting lost in fog as I am about getting all chummed up. We are invisible to powerboats, and we can assume they aren't listening to VHF. So I am very very conservative when deciding whether to make a crossing in thick fog. I can navigate fine, but other boats are really surprised when they are staring at their radar all day, and then they suddenly come across a kayak in the fog. They are definitely not looking for us on those days.

[leong]

Nate,

Yes of course. I went a little overboard. I've practiced with ranges many times. However, I don’t have good luck unless the range points line up directly with my desired COG, especially in rough seas.

My point was that most paddlers mistakenly think that a GPS works by lining up your heading with the waypoint so they still need to calculate a ferry angle if they want a COG directly to the waypoint. In effect, the GPS doesn't explicitly use ferry angles. The way it works is similar to using range points that line up directly with the desired COG.

If you mount a GPS on the front deck on a foam block sliced at a 45 degree angle I think it’s just as easy to see as a compass.

Of course, if you lose the signal or the GPS fails for any reason, you’re out of luck. So everyone should learn the traditional, time-tested navigation methods for a backup.

-Leon

PS
Here’s a novel use of a GPS: One year I entered the Great Stone Dam Classic kayak race on the Merrimack River. Before the starting gun went off everyone was lined up in the middle of the river. Then at the start everyone immediately paddled over to the left bank, apparently, to be in the slower current (the first half of the race was up river). I stayed in the center for a while and then paddled over towards the left bank, but to the right of the other competitors; i.e., I wanted to be in slightly deeper water. It seems there was some optimal point where the increased speed of the slightly deeper water cancelled out the slowdown due to the opposing current. I used my GPS’s speed indicator to help determine this “sweet” spot. I think it helped; I came in first for true sea kayaks and just behind two training surf skis.

[gyork]

Nate said:

The lobster buoys are crucial. If they are spaced less than the limit of visibility, you can stay on a perfectly straight bearing and nail your destination every time.

Agree with Nate that buoys are great aids to navigation for maintaining a straight course, though I will usually rely only on my compass and stopwatch whilst navigating in a thick soup, where buoy "pairs" are sometimes hard to locate, and the seas are typically calm. I'll often use buoys in high-visibility situations, and will use a set of buoys and my sighted destination (all in the same line) to determine the appropriate ferry angle, by observing my bow compass bearing when these are all "in-line" while paddling at my average speed. Then I can follow that bearing without continuing to line up near and far buoys that resemble all the others, especially if there is any chop.

..... I'm not nearly as worried about getting lost in fog as I am about getting all chummed up.

Gotta love that phrase!

We are invisible to powerboats, and we can assume they aren't listening to VHF. So I am very very conservative when deciding whether to make a crossing in thick fog. I can navigate fine, but other boats are really surprised when they are staring at their radar all day, and then they suddenly come across a kayak in the fog. They are definitely not looking for us on those days.

100%! Have found myself in a foggy solo situation leaving an island with rumble of multiple diesels, none of which were visible. Got the jitters and returned to shore, waited for the traffic and fog to diminish. Only the former did, with time, and I was very liberal with the securite calls that day. Nerve-wracking in these situations; attempts at dead reckoning compete with constant vigilance for the sounds of nearby vessels. Any amount of stopping and starting can throw you for a loop!

gary ("Chummy")