Adjusting Silva 70p compass

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mikkelkg
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Adjusting Silva 70p compass

Post by mikkelkg » Tue Jul 03, 2018 9:13 pm

Hi there,

I recently purchased a Tiderace Xcite Hardcore and had the dealer install a Silva 70p compass. However, I've noticed that the lubber line on the compass is a few degress off. Is this something I can fix myself? Can I loosen the screws slighty and then adjust the compass? The screws have all been given a small amount of sikaflex on the underside of the deck, do I need to reapply this?

I've attached a photo if needed.
Image

pathbrae
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Re: Adjusting Silva 70p compass

Post by pathbrae » Tue Jul 03, 2018 10:45 pm

It actually looks OK from the photo - it appears to be pointing straight along the kayak, but yes and (probably) yes. Loosening the screws a little will let you rotate the body of the compass. The most accurate way of lining up the lub-line is to run a string from bow to stern and line up on it - but most of us just do it by eye as the chance of getting within 5 degrees of a bearing while sitting in the cockpit of a floating sea kayak is small, even on a calm sea so a degree or so out isn't going to cause a huge problem. On an open crossing in fog or in the dark, I'd be "aiming off" from my target a few degrees anyway so I know which way to turn when I hit land to get to my destination. The more fickle the tides, the more I'll aim off.
So much sea - so little time to see it.

mikkelkg
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Re: Adjusting Silva 70p compass

Post by mikkelkg » Sat Jul 07, 2018 7:55 pm

Ok, thanks for the suggestions. I'll give it a shot with the string to check the alignment of the lubberline. Otherwise, you're probably right about the it not mattering that much.

I also discovered that the compass isn't entirely flush with the deck, as you can see on the attached photo. There seems to be a small (a few militers) gap. I'm wondering if it is because the compass is too large?

As mentioned, the compass is a Silva p70 compass and according to the instructions it should fit with all the Tiderace models.
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Allan Olesen
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Re: Adjusting Silva 70p compass

Post by Allan Olesen » Sat Jul 07, 2018 8:17 pm

The Silva/Garmin 70P quite often sits a few mm too high. You could cut a "gasket" out of a piece of rubber/neoprene and place under the frame.

Have you considered that those few degrees may actually be exactly right for the magnetic variation in your area?

So before you adjust anything, try pointing your kayak towards true north (which is easiest done by positioning yourself at a GPS coordinate which is exactly south of some visible landmark). If the compass shows 0°, be happy and let it sit where it is.

mikkelkg
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Re: Adjusting Silva 70p compass

Post by mikkelkg » Mon Jul 09, 2018 2:57 pm

You might have a point there, Allan. Will check it out.

The gasket idea is good - I'll see if I can get hold of some neoprene. Should it be placed between between the plastic mounting plate and the brass plate underneath that? Somewhere else I've read that you should just throw away the brass plate - any opinions on this?

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Re: Adjusting Silva 70p compass

Post by Allan Olesen » Mon Jul 09, 2018 9:38 pm

I would place it between the kayak and the brass frame.

I don't know the exact function of the brass frame. I have installed it because if I don't know what it is supposed to do, I can't know if I can remove it.

I guess the brass frame could prevent a lost compass if the plastic frame broke.

pathbrae
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Re: Adjusting Silva 70p compass

Post by pathbrae » Tue Jul 10, 2018 6:04 pm

I think - and I might be wrong - that the brass frame helps to allow the compass to be rotated in the mount once the screws are loosened a little bit by pushing the plastic housing up away from the base.
So much sea - so little time to see it.

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PeterG
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Re: Adjusting Silva 70p compass

Post by PeterG » Thu Jul 12, 2018 11:33 am

The brass frame seems to keep the lubber line in place, as it can rotate out of the way if you are not careful. You also don't want to restrict the bellows or you will get bubbles.

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Re: Adjusting Silva 70p compass

Post by mikkelkg » Sat Jul 14, 2018 5:04 pm

Hi again,

Thanks for all the advice. I've gotten hold on some 1.5 mm neoprene and will try and make a gasket out of this. I found this picture showing one where the gasket is placed between the plastic mounting plate and the brassplate, but I'm not entirely show how I will place it, yet.
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Re: Adjusting Silva 70p compass

Post by Incayak » Sun Jul 15, 2018 12:37 am

I fitted the same compass to a P&H Cetus and had to trim the plastic plate substantially to fit the recess in the deck. Without trimming the plate it just wouldn't fit flush to the deck. I drilled out the holes to accept stainless steel button head screws (from Screwfix) and fitted all together with plenty of Sikaflex to fill in any gaps. I'm pleased with the installation but disappointed that P&H couldn't make the recess fit for purpose in the first place.

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