Other details - the boat is a 2004 Alumacraft Magnum 175cs. I was going to install the heavy duty ratchet type mount flush with the gunwale which is light gauge aluminum plate covered with marine carpet. I was going to use 1/4 in. aluminum plates (one above and one below) as deck plates to reinforce and provide strength to the mount. I pretty much have the electrical stuff figured out (if I can remember how to solder), but was interested in what other peopole have done on where / how to install their antennas on aluminum boats like mine...

Eric,
I have an eight footer on a rachet mounted on the gunnel of my Crestliner 1750 Fishawk. I used a 1/4" backing plate. It works just fine. I can talk and hear the fishlakewinni.com fleet down to Black Point from Center Harbor. Just be sure on the position for trailering purposes.

Dean

Fishawk -- how far away is your antenna from where you would be / sit to use the radio (when you're transmitting not just receiving?). The Uniden manual recommends 6-ft...this might not work for me.

I have mounted the antenna on the port side just behind/adjacent to the console on the gunwale. The important thing is that you figure out how the antenna is going to ride and secured when laid down. You have every thing else figured out. The thing about not mounting the antenna near metal object is that the metal objects and people distort the transmitting patterns and people absorb the RF energy, something that we all live with.

Ghost - I was thinking of a similar arrangement on the starboard side, i.e, I'd mount the antenna few feet forward of my console as thats where its most convenient ! That way I would not have to snake the antenna cable through compartments, around a live well to get over to the port side.

I guess the manufacturers are covering their butts with these caveats. My Uniden Oceanus manual says keep at least 3-ft from small whip antennas and at least 6-ft from large antennas when transmitting. Of course its "OK" to keep a cell phone plastered to your ear.

Should I isolate the antenna mount / antenna with a rubber pad between the mount and backing plate? The Shakespeare ratchet mount came with a rubber pad and of course no mention of what to do with it.

Thanks for all the replies gents.

Approx. 3-4 feet. No issues so far (at least none that noticable)

I don't have an aluminum boat, but I do think they are covering their butts with the distances they show. My 8' antenna is only 2' away from a 3' am/fm antenna and I run both at the same time with no distortion to either.
As far as keeping away from people on the boat... unless you have a hard top or rocket launcher to mount to, its going to be pretty difficult to do. You'd have to "police tape" a six foot area around it to keep people out. That's just not gonna happen.
To me, it sounds like you'll be just fine with it a couple feet in front of the starboard console. That area would probably be less prone to someone wrapping a line around your antenna too... or tangling when fighting a fish.
Like you said... people are holding cell phones to their ears every day... and don't forget the guys that have handheld vhf, how would they get 6' clearance from the "waves"?
Go for it... you'll be fine. But just in case, better update the life insurance...hehehe

Before you drill any holes in the boat, check out the location of the antenna and see if there is any interference on all channels from the fishfinder and any other noise make device on board.

Thanks Slip and Ghost. Ghost -- good idea about the shakedown. I was already going to test for interference when transmitting (from antenna feedback) prior to "drilling holes" as per the Shakespeare people's suggestion, but you raise a good point. I think I'll install the radio but wait to mount the antenna until I can get on the water and docked / moored with all devices on and running to check out all potential sources of interference. Thanks again guys!

Eric,
On my Islander aluminum boat with a ratchet mount,I put on a rubber gromet over the small end of the antenna to travel. While it is laying down it keeps it from slapping the aluminum, and the antenna is tapered so it won't slide down when raised. Works out well.
Ernie.

Good idea Ernie thanks.

Has anyone mounted a smaller antenna on a bimini? The antenna would not be as long but you'd get the height...