Hi all
I've been agonizing over the nav lights on my cat. They are due for replacement after a brush with a wharf made one go away.
My question is, as the Port/Stbd nav lights will be separated by maybe 18 feet, should they be installed parallel with the hulls and thus have a dead spot between their arcs or should they converge slightly to give coverage at some optimum distance from the bow?
Centre mounting isn't really an option at the moment as there's no structure to mount them on easily.
Thanks in advance
Geoff
Sorry, dont have my colregs here. I would think off the top of my head that it should be a mast head tricolour.
However, I have seen lots of large cruising type boats with maybe 3-4 metres of beam run the navs each side of the cabin, so perhaps the dead zone is OK. Not sure I would be happy seeing a set of navs coming at me that suddenly just disappear.
Can't really do a Tricolour as it's a rotating mast, and it's mainly for inshore so deck level is better.
Good point about the cruisers though. A lot of those trawler types have the P/S lights on the sides of the cabin. They must have a similar dead spot in their lights.
Do the maths, even at 18 feet if they are in the deadspot you are about to hit them.
In theory there is a dead zone, in practice not so much. The source of light has a physical size, that is it stands a little clear of the masking, , and so you can see both red and green when at a distance. When really close up there is a dead band, but by then you can see the glow of light reflected on adjacent bits of the boat. If you watch a boat coming to anchor at night you will see what I mean.
I just searched the subject and found NSW RMS rules and rules from South Australian Dept of the Premier and they quote international boat rules.
Both rules state:
Side lights are red (port) and green (starboard) and shine from dead ahead to 112.5 deg aft on either side.
So I think thats straight forward. The port and starboard lights need to be visible from dead ahead to 112.5 Deg astern. No dead zone allowed.
And also no dead zone allowed from astern either due to this rule:
Stern lights are white and shine aft and 67.5? forward on each side. (Thus, the side lights and stern light create a full circle of light.)
Maybe treat the cat like a wide hulled mono ?
Seems that most websites just gloss over the issue for cats.
www.rms.nsw.gov.au/maritime/safety-rules/rules-regulations/night-safety.html
There is a paragraph in there about Optional Lights For Sailing Vessels. Perhaps that will cover you for your dead zone. Otherwise, you may need to fabricate something that is mounted under the forestay attachment point.
What are the other cats that you know currently doing?
Select to expand quoteJethrow said..
Can't really do a Tricolour as it's a rotating mast, and it's mainly for inshore so deck level is better.
Good point about the cruisers though. A lot of those trawler types have the P/S lights on the sides of the cabin. They must have a similar dead spot in their lights.
Question jethrow ...just delivered a Cat with a rotating mast. In swell or seaway the mast will rotate with the boom and lack of control seem a issue. Can you lock your mast in place with a brake or control lines?
A cat is no different to any other boat,there is plenty over 18ft wide with lights on the cabin sides, viewed from ahead you will clearly see the red and green, probably more clearly than if they were mounted together on the centre line, the separation of the colours would be more like 50 ft on a ship, but they of course should be mounted towards the bow, or at the front of the cabin,and pparallel to each other , someone would need to be very close to not see either of them,but I suppose it's possible. Offshore if I don't have a masthead tricolour I will run a masthead white light even if sailing,as it is much more easily seen at a distance than deck level lights.
Select to expand quotesouthace said..Jethrow said..
Can't really do a Tricolour as it's a rotating mast, and it's mainly for inshore so deck level is better.
Good point about the cruisers though. A lot of those trawler types have the P/S lights on the sides of the cabin. They must have a similar dead spot in their lights.
Question jethrow ...just delivered a Cat with a rotating mast. In swell or seaway the mast will rotate with the boom and lack of control seem a issue. Can you lock your mast in place with a brake or control lines?
Yeah Southace, I can with the control lines but it's a royal pain tacking and it's the question posted on another forum, how to make the system better!
Select to expand quoteJethrow said..southace said..Jethrow said..
Can't really do a Tricolour as it's a rotating mast, and it's mainly for inshore so deck level is better.
Good point about the cruisers though. A lot of those trawler types have the P/S lights on the sides of the cabin. They must have a similar dead spot in their lights.
Question jethrow ...just delivered a Cat with a rotating mast. In swell or seaway the mast will rotate with the boom and lack of control seem a issue. Can you lock your mast in place with a brake or control lines?
Yeah Southace, I can with the control lines but it's a royal pain tacking and it's the question posted on another forum, how to make the system better!
I think a break on the mast Bearing would be the most practical? Do you run a jib or headsail?
Select to expand quotesouthace said..Jethrow said..southace said..Jethrow said..
Can't really do a Tricolour as it's a rotating mast, and it's mainly for inshore so deck level is better.
Good point about the cruisers though. A lot of those trawler types have the P/S lights on the sides of the cabin. They must have a similar dead spot in their lights.
Question jethrow ...just delivered a Cat with a rotating mast. In swell or seaway the mast will rotate with the boom and lack of control seem a issue. Can you lock your mast in place with a brake or control lines?
Yeah Southace, I can with the control lines but it's a royal pain tacking and it's the question posted on another forum, how to make the system better!
I think a break on the mast Bearing would be the most practical? Do you run a jib or headsail?
I see that's in Albany
Is that the same Cat I saw come into Port Geographe last weekend?
Select to expand quoteJolene said..southace said..Jethrow said..southace said..Jethrow said..
Can't really do a Tricolour as it's a rotating mast, and it's mainly for inshore so deck level is better.
Good point about the cruisers though. A lot of those trawler types have the P/S lights on the sides of the cabin. They must have a similar dead spot in their lights.
Question jethrow ...just delivered a Cat with a rotating mast. In swell or seaway the mast will rotate with the boom and lack of control seem a issue. Can you lock your mast in place with a brake or control lines?
Yeah Southace, I can with the control lines but it's a royal pain tacking and it's the question posted on another forum, how to make the system better!
I think a break on the mast Bearing would be the most practical? Do you run a jib or headsail?
I see that's in Albany
Is that the same Cat I saw come into Port Geographe last weekend?
Yep she's finaly home.
Select to expand quotesouthace said..Jolene said..southace said..Jethrow said..southace said..Jethrow said..
Can't really do a Tricolour as it's a rotating mast, and it's mainly for inshore so deck level is better.
Good point about the cruisers though. A lot of those trawler types have the P/S lights on the sides of the cabin. They must have a similar dead spot in their lights.
Question jethrow ...just delivered a Cat with a rotating mast. In swell or seaway the mast will rotate with the boom and lack of control seem a issue. Can you lock your mast in place with a brake or control lines?
Yeah Southace, I can with the control lines but it's a royal pain tacking and it's the question posted on another forum, how to make the system better!
I think a break on the mast Bearing would be the most practical? Do you run a jib or headsail?
I see that's in Albany
Is that the same Cat I saw come into Port Geographe last weekend?
Yep she's finaly home.
Nice one! 
Sorry seen a couple of S&S out the corner of my eye but didn't get the chance to come and say hello.
Select to expand quote
I think a break on the mast Bearing would be the most practical? Do you run a jib or headsail?
Yeah, just jibs on a self tacker and zero's & assy's off the pole.
A break on the bearing would have to be planned from the start. I neglected to do this. 
