Well I got a Silva 70P compass. It came new in the box, but going on line for instructions it seems there is info on setting it for declination, which they call compensation, but when I look a the compass itself there are NO screws to adjust for east/west and north/south despite what the sheet says. Here is a link>>>
Anyone else have any experience with this issue?
It seems there are no adjustment built into the compass at all. If not it’s no big deal. I can navigate as easily from magnetic north as I can from grid north. But I have to be sure all my paddling partners are on the same “sheet of music” and all communications are designated Grid or magnetic. I have always used grid for my purposes for the last 50+ years, but if I can’t make an adjustment to the compass itself I’ll just use magnetic north and all headings stated from that system. So if I could dial it to grid north (16 degrees east from my location) I would not have to change anything from my land navigation to my water navigation.
So…am I missing something here? Do any of you know what Silva is talking about in their instruction from the link above?
According to that manual description and drawing, it looks like the compensator was an optional piece of hardware that screwed on underneath the compass, actually separate from the compass itself. If you don’t have that, doesn’t look like it will adjust. That piece has the N-S and E-W screws in it.
I prefer to work to grid north myself, as I can’t do the mental conversion arithmetic from my Boy Scout days anymore without getting flummoxed (“East is least and west is best.” Whatever!).
To that end, I offset the local magnetic declination (13.2 degrees east for the San Francisco Bay area) by rotating the compass “globe” inside the bezel/mounting plate, then tightening the 4 mounting screws.
The golden indicator feature now sits ~13 degrees to the “left”, and I can go from chart bearings to compass bearings and back without conversions.
It’s a little imprecise because the golden indicator feature is curved, so there’s parallax error now, but with my eyes and at 8 feet away, it’s good enough.
Well, so be it.
All headings and bearings will be called in Magnetic then.
I mounted the Silva today. Hope I can get it out at least a few times before the water all turns hard. My playgrounds will all be ice in a month or so.
I used my hand-held Brinton compass before now, and I had fun locating spots on the shores several miles away in the dark. It’s good practice. Not the ocean, but as close as I can come, to have some water for practice.
