Installation of compass

I just got a Brunton compass to fit the molded space on my cetus for it. It comes with 4 screws in the corners. Can I safely and effectively just screw them through the fiberglass? Should I drill pilot holes first? Do I need something under the fiberglass to also screw into for strength? Should I ignore the screws altogether and just glue or epoxy it down?

Thanks in advance for advice.


No Screws

– Last Updated: Jun-26-08 5:04 PM EST –

Screws aren't going to cut it.
I'm not sure of your exact configuration, but if you are going through the deck...
Get appropriately sized ss machine screws, nuts and rubber or neoprene washers...etc. You want to drill holes and bolt the compass down.
Once it is bolted down, I would use a little marine goo on the inside of the hull around each penetration to insure each bolt is water-tight.

screws are ok
Just get some plastic end caps to fit over the screws.

And yes, you want to drill pilot holes.

I’ve never tried screws in this manner, so I will defer to seakak1.

It just concerns me since some layups are fairly thin and I generally prefer not to trust a screw alone in a thin somewhat brittle material like FG.

consider nylon bolt/washer/nuts
Do pre-drill holes. Do not use screws.

Nylon weighs next to nothing. No rust. Plenty strong. Fewer potential sharp edges to cut you.

Add a dap of silicon (caulk) on the washers and you’ll be watertite.


pre drill
screws are okay…bolts are good. silicone around the holes. dab some on the underside where the screws/bolts come through. water tight.

No matter
Pre-drilling with a tiny drill bit is a good idea.

There are really no forces applied to the compass that require anything excessive to hold it in place. The suppled screws should be of the stainless non-magnetic type and will do a fine job of keeping the compass in place.

As others said, use something to cover the ends on the INSIDE of the storage compartment. If you don’t you will suddenly find holes in your dry bags.

Take a magnet to the hardware store
Some stainless steels attract magnets and some do not. When I went shopping for nuts and bolts to install my compass, I took a magnet to the hardware store to verify that the nuts and bolts did were not attracted to the magnet. Also, I used those locking bolts with the nylon grip and cut the bolts flush with the outside of the bolt so dry bags would not snag on them.

I’ve attached two Brunton(?) compasses to our 2 composite Valleys with the supplied screws. I’m pretty sure the instructions said to predrill and put a dab of silicone over the holes before screwing down the compass. I paddle an Avocet all the time on Lake Erie with no seepage in 3 years. I’ve started to paddle our Aquanaut ( which I now know I should’ve been doing the last couple years)and I’ve not noticed any seepage so far.

If you use bolt and nut …

– Last Updated: Jun-26-08 8:23 PM EST –

....... pre-drill w/ a bit just a wee bit larger than bolt (stianless w/self locking nut ,, or ,, nylon is good also) . If you use screws , recomend a backing (nylon blocks or simular) to screw into on the underside , if using a backing again pre-drill hole just a bit larger for screw to pass through without biting glass . The dab of silicon in the hole is good idea .

There are pop on caps (nylon/vinyl) that cover both screws and bolt ends if you need them .

It is a good idea to have a new compass "swung" (trued) after installation (Marina).

A compass w/ a light (night) and 1/2 hood (bright sun) are good also .

Remember , the compass is only as good as the "Chart" and "Plotter" and the one who is doing the pilotage or dead reckoning . Charts are drawn to "True North" and the plotter layed on a course line drawn on chart will give you a "TRUE" 'course' . You must add or subtract "Magnetic Variation" (given on chart) to establish a "Mag. Heading" (the heading you run on the compass to track a true course line)..... (bearing/waypoint/deviation/variation/wca)(connect the dots) . If you don't know where you are to begin with , the compass won't be of much help . But since you are getting one , you can have a great deal of interesting fun plotting courses and running them true , all the while learning basic navigation skills .

When proficient , you can run spot on in pitch darkness or solid fog , and that's rewarding ..

no holes, use adhesives
if you want a strong permanent mount, use a thick epoxy. there are many brands. Devcon makes a thick, non sagging slightly flexible (which is ideal) epoxy i think it’s called H2O for it’s underwater curability. for 10 bucks in a small twin tube set, you can do a very clean, hole free, and bombproof mount. just do the usual surface prep, clean, rough sand, etc, and bobs your uncle.

70P compasses
typically come with four demagnetized screws, a pilot-hole template, and instructions in Japanese English

compass installation
Thanks for all the suggestions. I got my compass by internet order, and it arrived without instructions or templates. Maybe it was the last display model or something.

There is a metal plate under the plastic frame which is also threaded for and held in place by the screws. It seems like it was designed to stay in place with the screws. The underside of the ball also floats in the housing. Since people have successfully used the screws, I think that is probably the safest way to go. I like the idea of nylon blocks to screw into under the fiberglass both for strength and as a permanent cover for the screw points.

Thanks again.