Dear Colleagues: any opinions re: the Raymarine radar/gps combination
and the model of choice(C80 vs C120)? Plan to install the instrument
on a rotating arm so it can be viewed from the companionway.
Thanks,
R Smith/Sentient
Hi Richard,
We are installing the same Raymarine C80 with 8.4" inch color display that supports the Radar and Plotter and interfaces with the ST60 Instruments. It is WAAS, of course. I can’t wait for the MARPA. It is amazing how concerned you can be when you can actually see all those ships out there. With the swing out arm, it is perfect. We have the Garmin 2006 C on that arm and this will be about an inch larger and still fit perfect.
We went with the 2kw 24 mile Radome, because of weight and size. It is 18" and that’s about as big as I can imagine on the mast above the staysail tang.
We won’t get lost or run into anything! We still hope to sail Aloha to Bermuda this June if we get all this done.
Safe Sailing
Kate
Kate Christensen
RogueWave Yacht Sales & Services, LLC.
1806 Dreams Landing Way
Annapolis, MD 21401 USA
410 571-2955 Office
410 703-5008 Cell
801 681-9741 Fax
kate@roguewaveyachtsales.com
http://www.roguewaveyachtsales.com
We have all internal halyiards in mast and mast head
electrical cables are in a tube. Where did you run
your antenna cable and how do you keep it clear of
lines? where did you exit cable (below floorboards?)
Nate
=====
nathaniel berkowitz, sausalito california
tel: 415 331 3314 fax: 415 331 1854
Kate,
Please contact me directly at jhiller@a…
Jim Hiller
Nate:
AO Halsey, s/v Polaris Jack, routed the radar cable down a shroud. I have seen this arrangement on gaff rigged cutters. The con is the cable is more exposed to the elements. The pro is the cable is supported most of its length.
We ran our radar cable through Iduna’s mast. This requires a 3/4" diameter hole for the cable plug to pass through. In addition, we ran the cable externally in the cabin. The idea behind this arrangement is the cable does not have to be cut when the mast is unstepped. (The array and cable are tuned. Cutting the cable is not advisable.)
Rod
S/V IDUNA
The thing I love about this group is the thoughtful level of discussion on such a wide variety of topics.
Reading this thread, Rod’s discussion of resolution and Kate’s mention of MARPA reminded me of some recent collisions at sea.
Perhaps the most startling one involved the container ship P&O Nedlloyd Vespucci and a yacht in the English Channel. From memory: The yacht was passing from port to starboard across the track of the container ship. The Vespucci was travelling at 15 kn in very dense fog. Both vessels had each other on radar and the Vespucci using ARPA determined that the yacht would pass ahead of them and that CPA was 0.4nm. Some changes of course were engaged in but the basic story
holds.
The Vespucci hit the yacht which then sank. The Vespucci was unaware of the fact until approached by maritime safety inspectors in Hong Kong! The yacht crew spent 5 hours in the raft until picked up (! rather than run down!) by a fast ferry.
The accident report showed that the manual for the Vespucci’s ARPA system stated that the resolution was less than the CPA reported. In other words the system was unable to determine between hitting the yacht and clearing it by 0.4nm. This is not just radar resolution it is also the target calculation system in the ARPA module.
This is not a solitary event. There have been a number of similar recent events. The message is beware - your systems can and do “lie” to you. This is the reason for the advent of AIS which uses VHF to broadcast position, course, speed and some other data automatically (try searching SOLAS and AIS).
We had a recent example of this when hove to in a SE gale in Bass Strait, early last December. Visibility was very bad when we saw the lights of the 7th close quarters ship! Repeated attempts to raise him on VHF failed. The the watch officer on one of the fast Bass St ferries came on and said “I have this vessel on my ARPA plot, the vessel you wish to speak to is vessel X”. Immediately the vessel in question broke in and after a short conversation we established that
they would miss us by something under one quarter of a mile.
Later investigation showed that the ferry was using an integrated combination of ARPA and AIS in order to be able to give us that assistance.
Just as an aside, of the seven vessels that night (2340 to 0300) two were fast ferries travelling at 27 knots, the balance freight and oil rig support vessels. The closest passing distance was 300 feet! I was having very detailed conversations with that vessel as they made an emergency turn to stbd. The most distant vessel was 1/4 of a mile.
Despite what COLREGS say about not using VHF as primary collision avoidance it was vital in this situation. My crew and I were very busy for a while! (We would see the loom of the decklights and immediately begin calling ‘unidentified vessel’ most vessels answered quite quickly however some vessels would not alter course until we could tell them which of their nav lights we could see. In the conditions this meant that they were very very close indeed - nav lights are hard to see in bad vis) We had no radar and painted no radar echo even though we had a Davis type reflector in the ‘double catch rain’ position. We were invisible despite a masthead tricolour light and a very bright torch on the trysail. In future I would hoist a strobe to the masthead (despite COLREGS) and broadcast the fact, along with my position in my all ships calls. These calls are very important. They led to us being called up by vessels as they approached in order to get an update on our position, or as one vessel put it “Mate, where are you? I should be right on bloody top of you and I can’t see you.” We exchanged positions and he was about a half mile away and ultimately passed closer - we could see him, he couldn’t see us!
The basic issue was that with the relative speeds - them at 15 - 27 knots and us drifting at 1 knot hove to - we had little if any capacity to effectively avoid a collision. We couldn’t move out of the way fast enough to avoid them, given the very poor visibility and the very difficult conditions (wind consistently around 40 kn and gusting up to 50, seas very steep and short 4 metres with some up to 5 metres and breaking).
Too busy for me. We’re heading back across on 4 February for the Australian Wooden Boat Festival in Hobart. There will be at least 6 of Lyle Hess’s designs there, moored all in a row. Hoping for some better weather!
Regards & Happy Australia Day (Jan 26)
Mike