Need Help Finding Instruments

[Harborless]

I am replacing an old Tachometer and Depth finder gauge but can not find the right size replacements. The diameter cut outs are 4 1/2" and most instruments are only in the 2-3 1/2" range. Does anyone know where I can find 4 1/2" diameter equipment?

Also, in relation to this I am installing dorades but once again I can only find diameters of 3 1/2 " when I need 4"

Are there some sort of ringed gaskets or some sort of material that one can use to fill in the gap and fit the equipment snugly? What do you do when you have a hole 4" big and equipment only 3 1/2" round? How do you fill the gap?

All help is appreciated.

P.S.-- Any idea where I should look for a 50 to 75 watt solar panel that I can mount off the railing of my sailboats transom? what is the price I should expect to pay for such wattage?

[poopdeckpappy]

Moor instrument

Also, there is plenty of 4" cowl vents out there, anywhere from $90.00 - $600.00 ea., PVC -Stainless

[mm2187]

When I replaced instruments on my sailboat I ran into a size issue also. I used Starboard which is a poly material which you can get in a variety of thicknesses and sizes. It cuts like wood but it maintenance free and easy to seal up with 3M 5200.

[Tim R.]

My previous boat had Datamarine round instruments. I do not recall the diameter. Either 4" or 4 1/2". Anyway, the Raymarine ST60 instruments with the flush mount adapter covered the old holes completely.