Low bridge !!.... and I don’t want to duck

[Blueone]

Pic for attention....plus I thought it was funny.... You can do it !!

so I was down at the new marina today because I am concerned about the bridge I have to go under.
From water to top of my radar is 12.5’.... bridge is around 15’. My standard VHF antenna is taller then 15’ and my anchor light is taller by roughly 12” then the radar. I do not want to put either one of them up and down for each passing... so a couple of questions.

1. I know Shakespeare sells shorter VHF antennas. What is the real world performance difference when comparing the two?

2. what is the rule or standard for your anchor light’s height?.... does it need to be a couple inches higher then the radar or is there a formula or some rule?

Bridge causing this anxiety

 

[tc410]

Says diy.com on the side.... How ironic is it that this represents the fate of many a do-it-yourselfer’s projects?

 

[Soulshine]

I’m in the habit of dropping my antenna but the light would be a hassle.

There may be a formal rule but I bought a very stubby all around anchor light for my previous boat. It was maybe 5” tall and made by Atwood as I remember.

 

[Z-Worthy]

You can make it under. I took our 40’ through there multiple times when the water was 12” higher than they’re calling for this summer. You’ll have plenty of room.

 

[Blueone]

You can make it under. I took our 40’ through there multiple times when the water was 12” higher than they’re calling for this summer. You’ll have plenty of room.

My antenna is 8’ and up high on the hardtop so for sure it won’t make it.... I was in a covered slip a few years back and thought I could remember to put the antenna down.... it was embarrassing.

 

[Fill Ess]

what is the rule or standard for your anchor light’s height?.... does it need to be a couple inches higher then the radar or is there a formula or some rule?

Looking in my USCG book, for a boat between 12 and 20 meters long, your masthead light should be at least 2.5 meters above the gunwale. And the light has to be visible for 3 nautical miles.

 

[b_arrington]

Maybe an electrically actuated hinge radar mount would help? Seaview Global makes one.

 

[Havana Shamrock]

Get a Shakespeare 4’ and move it to the side of your arch this way it’ll be fine and easy to stow for winter. I have (4) 4’ers and the range is great I pick up chatter alot further than I thought I would.

 

[Blueone]

Get a Shakespeare 4’ and move it to the side of your arch this way it’ll be fine and easy to stow for winter. I have (4) 4’ers and the range is great I pick up chatter alot further than I thought I would.

I have been reading a bit and the typical 8’ is 6db and the 4’ is 3db. The 3db signal wave is round which is good if you’re pitching or heeling like on a sailboat... the 6db is a more horizontal signal wave but it goes twice as far as the 3db.
I am on the Great Lakes and not usually more than 20 miles from shore...what I can’t see so far is distance for 3db or 6db. The other thing I am reading is the signal is line of sight... If I mount a shorter antenna where it is now...high up and side of hard top half the antenna would lose line of sight to Port side.
I am starting to think not worth the loss and stick with what I got... just remember to put it down.... and shorten the anchor light so only one thing to deal with.

 

[Havana Shamrock]

I guess because mine are up higher on my hardtop approx 19’ from the water they have good results? I’ve had comms from a great distance using them I hated the look of my 8’ers on the hardtop.

 

[BlueYonder]

 

[M Prod]

View attachment 102391

Pic for attention....plus I thought it was funny.... You can do it !!

so I was down at the new marina today because I am concerned about the bridge I have to go under.
From water to top of my radar is 12.5’.... bridge is around 15’. My standard VHF antenna is taller then 15’ and my anchor light is taller by roughly 12” then the radar. I do not want to put either one of them up and down for each passing... so a couple of questions.

1. I know Shakespeare sells shorter VHF antennas. What is the real world performance difference when comparing the two?

2. what is the rule or standard for your anchor light’s height?.... does it need to be a couple inches higher then the radar or is there a formula or some rule?

Bridge causing this anxiety

View attachment 102392

Hilarious photo. So no SB’s/pilot houses at the new marina I guess? My anchor light has a hinge but it would be annoying to go up there every time to lay it down. Too close for comfort for the radar regardless.

 

[tc410]

@Blueone, looking at your picture, I’d say you could lower the nav light maybe a foot. The technicality is another boat is supposed to be able to see the forward steaming light when you’re heading at them at night. We all know Sea Rays tend to run bow high when planing and when on plane. That’s why Sea Ray mounts them so high in order to clear the radar. I shortened mine quite a bit when I had the 410DA.

I think I’d stick with the 8’ antenna though. Folks with 4 footers on top of a fly bridge hard top are still probably twice as high as yours. Or you could always buy one of these for $600:

https://www.boemarine.com/taco-grand-slam-850-electric-vhf-antenna-mount.html

 

[techmitch]

View attachment 102391

Pic for attention....plus I thought it was funny.... You can do it !!

so I was down at the new marina today because I am concerned about the bridge I have to go under.
From water to top of my radar is 12.5’.... bridge is around 15’. My standard VHF antenna is taller then 15’ and my anchor light is taller by roughly 12” then the radar. I do not want to put either one of them up and down for each passing... so a couple of questions.

1. I know Shakespeare sells shorter VHF antennas. What is the real world performance difference when comparing the two?

2. what is the rule or standard for your anchor light’s height?.... does it need to be a couple inches higher then the radar or is there a formula or some rule?

Bridge causing this anxiety

View attachment 102392

@Blueone, looking at your picture, I’d say you could lower the nav light maybe a foot. The technicality is another boat is supposed to be able to see the forward steaming light when you’re heading at them at night. We all know Sea Rays tend to run bow high when planing and when on plane. That’s why Sea Ray mounts them so high in order to clear the radar. I shortened mine quite a bit when I had the 410DA.

I think I’d stick with the 8’ antenna though. Folks with 4 footers on top of a fly bridge hard top are still probably twice as high as yours. Or you could always buy one of these for $600:

https://www.boemarine.com/taco-grand-slam-850-electric-vhf-antenna-mount.html

There ya go... With switch, relay, wiring, hardware and install tc410 just cost you a Boat Buck!

 

[Blueone]

@Blueone, looking at your picture, I’d say you could lower the nav light maybe a foot. The technicality is another boat is supposed to be able to see the forward steaming light when you’re heading at them at night. We all know Sea Rays tend to run bow high when planing and when on plane. That’s why Sea Ray mounts them so high in order to clear the radar. I shortened mine quite a bit when I had the 410DA.

I think I’d stick with the 8’ antenna though. Folks with 4 footers on top of a fly bridge hard top are still probably twice as high as yours. Or you could always buy one of these for $600:

https://www.boemarine.com/taco-grand-slam-850-electric-vhf-antenna-mount.html

Taco has some interesting products... didn’t know about them

 

[carterchapman]

I have been reading a bit and the typical 8’ is 6db and the 4’ is 3db. The 3db signal wave is round which is good if you’re pitching or heeling like on a sailboat... the 6db is a more horizontal signal wave but it goes twice as far as the 3db.
I am on the Great Lakes and not usually more than 20 miles from shore...what I can’t see so far is distance for 3db or 6db. The other thing I am reading is the signal is line of sight... If I mount a shorter antenna where it is now...high up and side of hard top half the antenna would lose line of sight to Port side.
I am starting to think not worth the loss and stick with what I got... just remember to put it down.... and shorten the anchor light so only one thing to deal with.

View attachment 102402

Reach out to @nealtrombley - he Reps for Shakespeare. He may be able to offer you some advice.