What to do with old 3” instrument openings

[Layne Campbell]

We have an old hunter 35 that had 6 3” instrument displays in the cockpit depth, speed, wind, gps, autopilot, and then another one that I forgot. Most of them did not work anymore. We added a shmancy multifunctional display/chart plotter with a NMEA 2000 network that makes a lot of the old displays redundant even if they did work. I was curious what other folks have done with old 3” opening 4” square faced instrument spaces when they become obsolete. 3” multi displays are like $500 a piece, and we might get some of those, but what have other folks done to fill old empty holes?

Thanks

[Spot]

Hi Layne-
If you want something simple and inexpensive, just make some blank covers from some thin plastic or fiberglass, drill or use existing holes, caulk, and screw down.

[Franziska]

Are the holes in fiberglass?

If yes, take a thin piece of flexible plywood or cardboard slightly larger than all of them together.

If you can access the location from the inside:
Throughly grind the surrounding area with an abrasive disk from the inside. Dedust. Wipe with Acetone.

Proceed outside.
Take a piece of plywood, tape one side off with smooth plastic film.
Temporarily glue this piece with the filmside facing the holes to the location. Use a hot glue gun for this.

Proceed inside.
Carefully wax the exposed film visible in the holes.
Paint with gel coat onto the waxed area (match color on outside before catalysing).
Do not get wax or gel coat on the surrounding areas inside which you abraded.
Once gelcoat is in "green stage=slightly tacky", laminate several layers of mat onto the area, starting with patches the size of the holes and getting progressively bigger.
If it's not too hot you should be able to laminate 3-5 layers at once.

Let cure, remove plywood outside and finish the seams.

Alternativly grind all from outside, manhandle thin ply or cardboard through hole. Fix it with hot glue gun.
Laminate several layers of consecutively larger patches to fill holes.
Let cure. Sand flat and filler to surrounding and paint.

Last option glue a cover onto the location and give it a meaning/purpose by attaching something to it (winch handle holster, I pad holder, cup holder...).

Good luck!

[Layne Campbell]

Thanks for the detail responses, I have 1/8” thin white phenolic sheet that works pretty well for this type of thing. I will probably get one or two multi-displays and then patch the rest of the openings.

I am surprised to not find things like inexpensive 12V clocks, thermometers, or voltage displays that are specifically designed to fill old instrument spaces. It seems like a lot of old boats have a handful of the ubiquitous 4” square instruments that have long sense stopped working.

[CaptTom]

Originally Posted by Layne Campbell

I am surprised to not find things like inexpensive 12V clocks, thermometers, or voltage displays that are specifically designed to fill old instrument spaces. It seems like a lot of old boats have a handful of the ubiquitous 4” square instruments that have long sense stopped working.

I was thinking the same thing. I ended up putting a round marine stereo receiver in one hole. That worked out well. I've seen cigarette lighter sized voltage displays, clocks, etc. But not 3- or 4-inch ones.

[Tillsbury]

I see what you mean when there are six! Many boats only have a few of these and chart plotters are no substitute for individual displays however fancy, so it probably doesn't come up that often. Surely anything but matching displays would look as scruffy as blanking plates?

If I had a row of six over the companionway I'd probably go with a piece of teak over the lot, with new holes cut for the displays I wanted. I recently did this with the back of my cockpit table, which had all sorts of displays haphazardly in it. I moved out a few, redeployed the fuel gauge to nearer the engine controls, then covered all the back section with wood and cut a new hole in that to mount the old chart plotter as a backup.

[Time2Go]

A few months ago Mads on “Saillife”
A youtube channel did this exact project
Worth a look
Cheers
Neil

[Boatyarddog]

Originally Posted by Layne Campbell

We have an old hunter 35 that had 6 3” instrument displays in the cockpit depth, speed, wind, gps, autopilot, and then another one that I forgot. Most of them did not work anymore. We added a shmancy multifunctional display/chart plotter with a NMEA 2000 network that makes a lot of the old displays redundant even if they did work. I was curious what other folks have done with old 3” opening 4” square faced instrument spaces when they become obsolete. 3” multi displays are like $500 a piece, and we might get some of those, but what have other folks done to fill old empty holes?

Thanks

Amazon.com
Search Instrument hole plugs 3"
SV Cloud Duster

[foufou]

I use G-10 to fill the holes. Same thickness as hole laminate. If you have access behind the hole you can back up the hole insert with layers of glass and epoxy to ensure it will not get knocked out. If you don't have access behind the hole you can slip two pieces of G-10 through the hole and epoxy them to the back of the hole to give a layer to glue the hole insert to. fill the joint with micro-balloons and epoxy, sand, fair and paint. Have fun patching. F

[Pete7]

We switched from 4 to 3 a decade ago when I installed a set of ST60s. I bought an off cut of teak, cut to shape and varnished.

Useful to be able to take the facia out to check connections occasionally.

[TrentePieds]

Spot in post #2 is spot on :-)!

TrentePieds

[Juho]

We covered one somewhat bigger hole with a tablet size cover that serves now as a tablet holder.

[ramblinrod]

It always pains me when I see someone cutting FRP to mount instruments. They will need replacement long before the boat goes to the boneyard. Many have cut holes in the companionway bulkheads to mount compasses and instruments. It ruins the best seats in the house when kicking back in the cockpit in an anchorage, and inevitably crew is always sitting in front of them when underway.

I like the instrument enclosure on the companionway slider when it does not obscure vision from the helm. Else a pod at the helm seems the best way to go.

The ultimate fix for old instrument holes is FRP and gelcoat to return the boat to original. Thin plates are OK, but certainly second best. With MFDs there just isn’t the need for so many instrument displays anymore.

[hamburking]

I had two holes as you described, next to the companionway hatch. I installed a couple flat, round, inspection port covers. They were inexpensive, a good fit, and looked good. Plus my kids enjoyed taking them off from time to time and sticking their hands out the hole like some kind of monster.

I think they were at least 4 inch, maybe even bigger. There was originally a (broken) compass and an instrument of some kind.

[Layne Campbell]

wow, I love the teak pod over the companionway. Also, the inspection ports look like they would be nice and clean.

we have two instruments on the bulkhead on the starboard side, the rest are on a bennical pod. I am currently thinking of covering the two center openings on the bennical pod with a tablet mount, and putting a multi display on one side and the auto pilot control on the other side. the water speed currently works and is on the bulkhead so then we just either need to patch the depth display on the bulkhead or replace it with a new depth display.

I have half a mind to start a side company making economic marine instruments that could serve this purpose, It seems like Air temperature, Battery voltage, Time of Day, and heading would be pretty easy to enclose in economical displays which would only need a power connection and would not network in any way. It would probably be too much work, but at least I feel better knowing I am not the only one who has hun into this sailing frustration.

-Layne