Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 19-01-2020, 22:48   #16
Moderator
 
Adelie's Avatar

Join Date: Feb 2010
Location: La Ciudad de la Misión Didacus de Alcalá en Alta California, Virreinato de Nueva España
Boat: Cal 20
Posts: 9,599
Re: Mast-mounting radar

Quote:
Originally Posted by a64pilot View Post
I believe a mast is in compression and therefore holes aren’t as big a problem, however smoothing out the edges of the holes with sandpaper etc will go a long way towards preventing cracks.
Just like the serrations on a candy bar wrapper, a hole with nicks on it has stress risers and you can be sure where the crack will start.
A tremendous number of boats are out there without cleaned up holes, it’s just good practice is all.
Besides it will help prevent chaffing of the wires.


A mast is in compression and bending, even if you are not intentionally trying to bend it.
Holes are best in the sides of the mast, preferably near spreaders or intermediate shrouds.
__________________

__________________
Num Me Vexo?
A house is but a boat so poorly built and so firmly run aground no one would think to try and refloat it.
Adelie is offline   Reply With Quote
Old 19-01-2020, 23:17   #17
Moderator
 
Adelie's Avatar

Join Date: Feb 2010
Location: La Ciudad de la Misión Didacus de Alcalá en Alta California, Virreinato de Nueva España
Boat: Cal 20
Posts: 9,599
Re: Mast-mounting radar

Don Dodd’s in Modern Seamanship recommended a radar antenna height of 16-32’ above water, minimum 12’ above highest deck you could stand on.

The minimums had to do with safety due to irradiation, especially the eyes and that you weren’t going to see anything closer than 75’ due to pulse length which translates into 16’ vertical.
32’ was not a hard maximum but more the point he drew a line on diminishing returns. You could bump it to 50’ but that only adds 2nm miles to the radar horizon.

In total he recommended a 24nm range model or less, wasn’t much point in longer ranges since you could no mount the antenna high enough to get that range on anything floating. For high terrestrial returns or returns from weather 24nm or longer might be useful but probably not.
__________________

__________________
Num Me Vexo?
A house is but a boat so poorly built and so firmly run aground no one would think to try and refloat it.
Adelie is offline   Reply With Quote
Old 20-01-2020, 02:24   #18
Registered User

Join Date: Nov 2019
Posts: 549
Re: Mast-mounting radar

Quote:
Originally Posted by Adelie View Post
Don Dodd’s in Modern Seamanship recommended a radar antenna height of 16-32’ above water, minimum 12’ above highest deck you could stand on.

The minimums had to do with safety due to irradiation, especially the eyes and that you weren’t going to see anything closer than 75’ due to pulse length which translates into 16’ vertical.
32’ was not a hard maximum but more the point he drew a line on diminishing returns. You could bump it to 50’ but that only adds 2nm miles to the radar horizon.

In total he recommended a 24nm range model or less, wasn’t much point in longer ranges since you could no mount the antenna high enough to get that range on anything floating. For high terrestrial returns or returns from weather 24nm or longer might be useful but probably not.

If I remember correctly...regulation for the oceanic racers is radar to be mounted a minimum of 3.5 meters above sea level
Attached Thumbnails
Click image for larger version

Name:	26FFA1F5-0A1B-4F69-8D6F-9FAC71B837BD.jpg
Views:	42
Size:	423.4 KB
ID:	207296  
slug is online now   Reply With Quote
Old 20-01-2020, 04:38   #19
Marine Service Provider
 
Snore's Avatar

Join Date: Jan 2011
Location: St. Petersburg, FL
Boat: Tartan 33 and OPB
Posts: 2,668
Send a message via Skype™ to Snore
Re: Mast-mounting radar

Quote:
Originally Posted by Adelie View Post
A mast is in compression and bending, even if you are not intentionally trying to bend it.
Holes are best in the sides of the mast, preferably near spreaders or intermediate shrouds.
I respectfully think you are over analyzing. How many masts have failed at or because of the radar mount?

Since the mast creates a blind-spot and the profile of the side of the mast is much larger than the profile of the front, placing the radar array to the side gives a larger blind spot. IMHO, even if the blind spot is to my starboard (stand on) side, it is still less desirable than having the blind spot to my stern.
__________________
"Whenever...it requires a strong moral principle to prevent me from deliberately stepping into the street, and methodically knocking people's hats off- then, I account it high time to get to sea..." Ismael -a link to my delivery website is in my profile—
Snore is offline   Reply With Quote
Old 20-01-2020, 08:57   #20
Registered User

Join Date: Mar 2017
Location: Pensacola, FL
Boat: 1982 O'Day 37
Posts: 28
Re: Mast-mounting radar

I was just going off what I read, I'd seen multiple sources say ideally you want the radar 12' off the waterline, which I thought was awfully low (I have 5 ft of freeboard already, that could get knocked around by my headsail pretty badly)... looks like I should do some more research on that...
jholovacs is offline   Reply With Quote
Old 24-01-2020, 19:00   #21
Registered User

Join Date: Apr 2012
Location: wherever
Boat: Cheoy Lee 47 CC
Posts: 868
Re: Mast-mounting radar

I mounted a new broadband on my mast last year.
Mine is mounted about 18 feet off the water, it hasn't happened it close range performance.
On my B&G the plugs were small enough not to require a large hole.
The one thing I'd like to change is the mount. I had a boat prior to this one that had a swivelling mount, it kept the radar parallel to the earth.
When heeled over with a fixed mount I get sea clutter on the low side and reduced range. On the high side it's just the opposite, I can't anything up close. Fortunately I can still see distant squalls at a decent range but not so good on the low side.
One of the reasons I bought broadband was the ability to see squalls in more detail. On that level it was a worthwhile investment.
lifeofreilly57 is offline   Reply With Quote
Old 24-01-2020, 19:23   #22
Registered User

Join Date: Nov 2019
Posts: 549
Re: Mast-mounting radar

Quote:
Originally Posted by lifeofreilly57 View Post
I mounted a new broadband on my mast last year.
Mine is mounted about 18 feet off the water, it hasn't happened it close range performance.
On my B&G the plugs were small enough not to require a large hole.
The one thing I'd like to change is the mount. I had a boat prior to this one that had a swivelling mount, it kept the radar parallel to the earth.
When heeled over with a fixed mount I get sea clutter on the low side and reduced range. On the high side it's just the opposite, I can't anything up close. Fortunately I can still see distant squalls at a decent range but not so good on the low side.
One of the reasons I bought broadband was the ability to see squalls in more detail. On that level it was a worthwhile investment.

I have sailed with both gimbaled and fixed mast mounted radar

I can’t see any difference in performance

With a fixed radar I have seen sea turtle backs, seal herds, ice blocks, ship wakes , long line bouys...

Gimballed may provide more performance ..it definitely is more fragile and more expensive
slug is online now   Reply With Quote
Old 25-01-2020, 22:05   #23
Registered User
 
jeff356's Avatar

Join Date: May 2018
Location: Middle River, MD
Boat: Hunter 356 35'6"
Posts: 26
Re: Mast-mounting radar

Already have the radar and mount and just need to mount it just above the first spreader along with a deck light, so very relevant thread.
An additional question is what to use for the mount, drill and tap for screws or just rivets? Will use tefgel but not sure which way to go?
Jeff
jeff356 is offline   Reply With Quote
Old 25-01-2020, 22:58   #24
Registered User

Join Date: Sep 2017
Location: Langley, WA
Boat: Nordic 44
Posts: 1,020
Re: Mast-mounting radar

Quote:
Originally Posted by jeff356 View Post
Already have the radar and mount and just need to mount it just above the first spreader along with a deck light, so very relevant thread.
An additional question is what to use for the mount, drill and tap for screws or just rivets? Will use tefgel but not sure which way to go?
Jeff
I suggest rivets. Screws can vibrate loose.

Tefgel is a greasy product. I had a boom gooseneck get very loose when the bolts backed out due to Tefgel. Tefgel works good with rivets. For bolts I prefer Duralac but it can be difficult to find. Duralac hardens up, Tefgel stays greasy.

Almost 30 years ago I used rivets to attach a Radar bracket to my mast. The mast has been repainted twice and the Radar replaced once but I am still using the original bracket held in place with the original rivets.
stormalong is offline   Reply With Quote
Old 26-01-2020, 02:19   #25
Registered User
 
BigAl.NZ's Avatar

Join Date: Sep 2008
Location: Auckland, NZ
Boat: Hood 38 - Wauquiez
Posts: 404
Re: Mast-mounting radar

Our Raymarine Quantum 2 had wireless, we had the cable too, but gave the wirless a try. It has been good, so we just ran power cable.

Just above first spreader, with scanstruct mount and radar protector bar.

Been pretty happy with it. We will loose a small channel buoy about 5-10 from boat.
__________________

BigAl.NZ is offline   Reply With Quote
Reply

Tags
mast, radar

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Radar Mounting: On Mast or Stern Pole ? Resolve78 Monohull Sailboats 30 07-02-2018 14:48
Mounting deck hardware - g10 mounting pads? alaskanviking Construction, Maintenance & Refit 8 21-10-2017 22:06
For Sale: Radar Mast Mount, Mast Safety 'Granny' Bars w.posner Classifieds Archive 1 13-03-2013 10:12
Radar Mounting: Mast or Stern Post ? pjazz Marine Electronics 13 11-11-2010 15:14
Mounting A Radar On A Windgen Pole?? Hubec Marine Electronics 3 04-03-2008 20:01

Advertise Here


All times are GMT -7. The time now is 16:28.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.