Rigging a C-Dory

[Sneaks]

Jenny B delivered Thursday. Yay! Now the tedious stuff, rigging it. The big job - anchor windlass - I'm saving for a cool day and hope it only takes one trip to West Marine 'cause that's a 52 mile round trip.

Question for the folks with 8' antennas mounted in the "blind spot" just behind the running light. Did you use a backing plate or will large washers suffice? Did you move it slightly aft of the blind spot so it would lay down without requiring a lanyard or hook to keep it on the boat?

[Coastie Dory]

Hi folks,

You might consider getting a rail mount and mounting the antenna on the cabin top. It works well for me because it keeps the walk way around the cabin clear which is very helpful in poor weather and night ops. One less thing to trip you or catch a PFD on. The rail is already sturdy enough so no backing plate issues. I use a cable pass-through available at most marine stores to make a weather tight seal around the cable. A disadvantage of this set up is the antenna becomes an eye poking hazard when folded back and you are standing in the cockpit.

Stainless fender washers would probably be ok for the cabin wall. Since you can see the back side of the mount arrangement, a plate may look better and be even stronger.

Best of luck, Randy Sheehy.

[Chuck S]

Bigger is not always better.

An 8' VHF antenna is poorly suited for any boat the size of a C-Dory because the radiation pattern is very narrow and any heel, or pitch just sends your transmitting power into the sea or sky. If you're on your trailer these work fine. If you're a 40 footer they work well too.

The shorter whips have a much broader transmittion pattern and work better at any angle of heel and with the boat wobbling around.

VHF is limited to the horizon anyway, and that's not real far with the antenna this close to the ground.

-- Chuck

[C-Hawk]

Sneaks

Here's some good reading from the WestMarine Advisor on selecting an antenne-
WestMarine Advisor
You need a tall antenne with a high db rating in order to have farther reach. Mount the antenne as high as you can.
The 8' antenne works great on my 22'.

[Sneaks]

Let me guess, Chuck, you come from a sailing background?

Without getting into a techie nitpick session, the name of the game in a small boat is Effective Radiated Power (ERP) and antenna height. Once past the simple vertical 1/4 wave antenna, the higher the ERP and, as you correctly pointed out, the narrower the beamwidth.

Multiple lobes also exist on all gain antennas though, including the 4 ft. versions, and I've had zero problems communicating in the past with 8 footers on my 22' and my 32' anywhere I operated offshore. Probably because I never had the occasion to stay heeled over long enough to totally interrupt communications. The plus is that I can and do eavesdrop on the sportfishers when they hit a bite.

Bottom line, I have an 8 ft. antenna, I like the looks of an 8 ft. antenna, and they work well where I cruise, hence the location questions.

Bag sailors put their antennas way up on the mast, overcoming the inevitable absorption and radio horizon at lower heights. Heeled over with 9db+ antennas can and do present problems for them and would for me if I heeled at 20 or 30 degrees for long periods.

Actually, I'm amazed that my little Icom picks up fishing chatter right now, with the antenna standing in a corner of my garage which is 4 miles and 1 hill between the ocean and here. Not much, but certainly enough to know everything is working.

Roger, my only question is in regard to the blind spot location. Is yours on the side and if so, how far behind the running light?

[C-Hawk]

Don-
I have my antenne mounted on my mast. Check my photo album pic#1. For me, the higher the better (except when I'm cruising the Delta)
Hope to see you guys at one of our So Cal cruises.