Hull 600 Adding A Raymarine C120 Multifunction Display & Radar
By Norm Perron


Eight and one-half years after hull 600 was commissioned, it was time to upgrade to a radar with newer features. The original radar, Autohelm 7" ST-50 (basically same as RL9) was installed on the pedestal, with the antenna on the mast. I was looking for a system with more bells & whistles, and, after much research, decided to buy a Raymarine C120 display with a 4 KW Pathfinder antenna. It lacks some of the features of the E series display (repeater at another location, bird’s eye photo view, bathymetric view of the bottom), but is priced closer to my budget. Plus, I have no interest in any of those other features. The whole project took me (and my wife assisting) about 7 full days. Not bad, considering how much I learned about the system and the cost savings. Below are the major steps we took for the installation and some of the challenges we encountered. 


1. I decided on the same configuration for the new radar system as I have now, which is with the antenna mounted on the mast. The new system required a 25 meter cable, which would also require a larger diameter cable than the existing one, because of typical voltage drop at the amperage of a 4KW. A 2KW would require a larger diameter cable as well. After much consideration, I decided that this would be the right time to upgrade the bent pedestal guard from the current 1” to a 1.25” guard, which is what is installed on today’s boats. A second reason to replace the guard with the larger diameter tube is that I needed more clearance above the compass for the new radar display. This part of the entire project became more and more challenging. The white plate below the compass that supports the pedestal would not fit with the larger diameter tube, so that plate needed to be replaced. To do this, the binnacle had to be taken apart. Then the ‘feet’ of the tube were not large enough to accommodate the 1.25” diameter, so those had to be replaced with new holes drilled into the cockpit floor. The big advantage is that it was a good time to lubricate much of the Edson steering & put plenty of antisieze compound on the screws. Finally, after replacing the bent guard, running the wires through it was not that tough. I used PLENTY of clear wire lubricant (like yellow-77). 


2. Running the new cable from the pedestal, under the cockpit, through the cabin floor, and to the mast was pretty simple, just followed the existing cable. That is around the diesel and right through the center of the boat right under the sole.


3. "Bending" the cable (at the base of the mast) so it would go up the mast was quite a challenge on a pullman berth boat. The 50-gallon water tank, which is under the bunk, needed to be removed. The existing hole at the base of the mast with old radar cable was too small to make the bend for the larger diameter cable. It was great practice enlarging that hole, with the old radar cable still in it. With a 1.5" hole saw, I drilled another hole just above the existing one, trying not to destroy other cables. Then, with lots of filing, I joined the holes so the larger cable could be passed.


 4. Now it's time to disconnect the old 2 KW antenna, lower it and drill out the 12 rivets holding that bracket. I didn't trust the existing radar’s mast mount with the new and heavier antenna. Besides, the 4 KW wouldn't fit on that mount. Luckily, I was able to salvage 1/2 of the rivet holes in the mast. It's quite a job determining exactly where the holes need to be drilled and actually drill them while perched in a bosun’s chair. I decided to stay with the supplied 3/16 aluminum rivets.


 5. Of course, the hole where the old cable exited the mast was not large enough. I drilled a 5/8 hole just above that old one. Then joined the 2 holes by lots of filing (same as I did at the base of the mast), being sure to keep the cable intact.


 6. The toughest part was pulling the new cable up the mast, using the old cable as a messenger. TONS of wire lubricant was used. This definitely required two people: my wife pushing the cable into the mast (applying as much wire lubricant as possible) while I used the old cable as a messenger and pulled the new cable from the new antenna location. I understand most installers cut this cable at the base of the mast so gravity can be used to help the cable down (pushing it in at the antenna) instead of pulling it up the mast. Getting the connector that attaches to the antenna through my enlarged hole was also quite a challenge. In hindsight, I should have made a larger hole.


7. Tasks were then pretty much done on the mast, so it was time to lift the antenna up & secure it on the mount. Not that tough of a job, but time consuming. Once it was mounted, with anti-sieze applied & the bolts torqued, the task of attaching the 4 power leads & connector were complete.


8. I also decided to replace my Garmin GPS chartplotter with a Raystar 125. The old Garmin GPS antenna was originally installed on the starboard stern pulpit, so I needed to remove that & mount the Raystar there, running the wires inside the pulpit. That was not a big problem.


The power cables were then connected and the system turned on. Presto, it worked, though it took time to actually figure out how to turn on the radar portion & see targets. The next day we did a harbor cruise seeing targets we never thought possible with an older 2 KW radar. I remember seeing 2 boats about 5' apart, actually saw 2 targets on the display. Being able to overlay the chart on the radar is fantastic. Seeing how MARPA tracks targets to avoid collisions is also fantastic. We are both very happy with the results.


The big question, would we do it again? I think so, even thought it was a really big job.

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