Copyright 2017 Karl D. Lahm
Voyageur, under a prior name and owner, had a Raymarine RC420 chartplotter mounted at the starboard helm. That was not much help to the helmsman when on the opposite tack, and it had to be placed before each sail and removed after. Having acquired a new B&G Zeus2, for all of its sailing-specific capabilities, I wanted to mount it in the cockpit, in a place where it would be accessible from both helms. The aft end of the cockpit table seemed a logical place, as that’s where MFDs are mounted on newer twin helm boats. And the table pedestals provided a means of hiding the MFD’s cabling to the boat’s NMEA 2000, Ethernet, and NMEA 0183 networks.
But, how to do it? Here are the considerations and potential problems:
* The table is only 20 mm thick, incapable of adequately supporting a suspended pod over time, unless the screws fully penetrate the table and there’s a backing plate atop it, which would ruin the aesthetics of the table (such as they are).
* If mounted to the underside of the table itself, the wires cannot exit the base of the pod, as intended by the pod manufacturer, because the surface to which the pod is mounted (the table) gets in the way. Cutting a hole elsewhere on the back of the pod leads to all manner of water ingress concerns.
* Most off-the-shelf pods aren’t suitable, because either (a) they can’t be rotated for best visibility from each helm or (b) they cannot be tilted for the best view when suspended. They are designed for cabintop mounting on power boats.
* A hole must be drilled in the table’s aft support post for the wires to pass through, on their way down the post, through the deck, and onward to their destinations. More water ingress concerns, not to mention aesthetics.
* There is no good way to extend the table aft, other than to make a new table.
Many different ideas were postulated, but none addressed all concerns.
I chose a Seaview PODW-3-1UC. This pod has an aluminum stem and is adjustable in multiple dimensions, exactly what’s needed for under-the-table mounting on a twin-helmed boat. There’s a rather large rotational moment at the point of attachment to the table and only 4 mounting screws used by that stem, so adequate material at the point of attachment is a necessity.
The concept of fabricating a new table was becoming more acceptable, until an inspiration hit me. I modified the table using two pieces of 12 mm (½”) King Starboard, each from the table end just past the inner lip of the post collar, of width nearly equal to the table. The Starboard is screwed and epoxy glued to the bottom of the table. This solves the “inadequate material” issue with the table, as there is now around 30 mm (1¼”) of material for the pod’s mounting screws to bite into. An identical Starboard plate was placed to host the forward pedestal collar.
With the help of a woodworking neighbor, a slot was cut in the aft Starboard plate, from the point of attachment of the pod to the center of the aft pedestal collar. This slot provides a nifty solution to the wiring issue, as the wires can go through the base of the pod, as its manufacturer intended, and enter the aft pedestal from its top, without cutting anything. Photo 1 shows the slot before the mounting of pedestal and pod collars. Four screws hold the Starboard thickening plate to the bottom of the table, as does epoxy glue between the layers. The remaining holes are for the pedestal and pod collars. Photo 2 illustrates the completed configuration, with cables installed.
Photo 1: Slotted Plate Under Table Photo 2: Completed Under-Table Assembly
Getting the wires below deck without much risk of water ingress was another challenge. Borrowing an idea seen in one of the sailing magazines (was it Good Old Boat?), I decided to embed a PVC pipe tube in the deck, sealed with 3M 4200 sealant, and run this tube up through the aft table support pedestal, with the wires exiting the tube at its top. The only way water will get into the tube is in the event of a knockdown, when far larger issues of water incursion will be present. The end result is a rather neat and clean installation, without loose wire bundles and such. While I can’t remove or change table tops on a whim, it will not be excessively difficult to replace the original white table with one of varnished teak, should I ever want to do that.
Photo 3: PVC Pipe Inside Pedestal Photo 4: Table/Pedestal Assembly
I ran the cables up through the PVC pipe, inside the pedestal and its mounting collar, through the slot cut in the Starboard and through the instrument pod collar. Photo 3 above shows a mock-up of the PVC pipe and pedestal base installation, which was done to ensure that these components fit together properly. Photo 4 shows the table assembly being placed atop the hole in the deck drilled for the cables.
From the hole in the deck, the cables proceeded aft, between the deck and the aft berth’s ceiling liner, to the steering cable box at the aft end of the aft berth (Voyageur has the “owner’s” interior layout, with one large aft cabin, not two smaller ones). First, to get an idea of the adventure ahead, I cut a circular hole, large enough to get my hand through, in the steering cable box, as shown in Photo 5 below. Then, sticking my camera up into that hole, I took Photo 6, which shows the gap between the deck and the aft berth ceiling liner, looking forward. If you have the twin aft cabin version of the boat, this will involve considerably greater contortion and obscenities! The wire sleeve on the left carries 12V power to the luminary aft of the engine. I presumed that, if this had been run, the other side of the center divider notch would also be free of obstruction. I was wrong. The enemy is dollops of adhesive between the two layers, such as the beige bubble seen between the layers in the photo above. If you are truly lucky, none of these obstruct the pathway to the deck hole below the aft table pedestal. I do not know if Jeanneau placed these adhesive dollops at locations that were precisely repeated from boat to boat, but I fear that placement might have been left up to the factory staff that was assembling these pieces. Blockage can be determined by running a rigid (steel or fibreglass) wiring fish-tape along the path and measuring how far it goes before it encounters any obstruction. Measure the penetration distance of the tape and the distance from the tape to a reference point that you can duplicate atop the deck, such as the temporary tiller port. Then measure that distance from the reference point forward on the deck, to see if it reaches or exceeds the expected position of the deck hole. DO THIS BEFORE CUTTING THE HOLE IN THE DECK!
Photo 5: Access Hole in Steering Cable Box Photo 6: Between Deck and Liner, Aft End, Looking Forward
In my case, there was a dollop of this adhesive that partially obstructed the path from the deck hole into the gap between layers, at the hole. I had to cut this out, using a Dremel power tool, to ensure adequate clearance for the cables and their connectors, as shown in Photo 7 below. The gray material in the upper side of the hole is the adhesive that needed to be cut away. The hole was recessed down to the wood to provide support for the PVC pipe through which the cables would run. Aside from the obstructing adhesive issue, running the cables through the deck and back to the steering cable box was straightforward. Pull strings were used, shown in Photo 8, pulled in using the rigid wiring fish-tape. They were tied to the small level tool to avoid accidentally pulling any out. Cables were then bound to the pull strings, fed by hand through the hole, and then pulled aft.
Photo 7: Hole in Deck for Cables & Tube Photo 8: Cable Pull Strings in Deck Hole
Prior to pulling in the cables, the aft end of the pull strings were temporarily tied to the steering quadrant, as seen in Photo 9, to avoid accidentally pulling them out.
Photo 9: Pull Strings Tied to Quadrant Photo 10: Cables Pulled Through Deck
In the end, cable placement was neither easy nor difficult. I installed two NMEA 2000 backbone cable segments, one from the port helm and the other from the starboard helm, to the centerline, inside the steering cable box. At the point where the N2K drop cable for the MFD exits the space between the deck and the ceiling liner, a N2K tee was installed, connecting the backbone cables from each side and the MFD. A prior owner had run a 12V power supply cable, for the prior MFD at the starboard helm, along the same path inside the steering cable box. I slackened it, spliced in the 12V cable to the Zeus2 MFD, and then pulled that cable and the N2K drop cable outward, at the pod, to hold these junctions tight up against the forward end of the steering cable box. Cable ties/pads were placed as far into the steering cable box as could be reached from either end of the box, to ensure support and prevent tangling of MFD electronic cables in the steel cables of the steering linkage. The Ethernet cable was routed to the port helm area, where a Navico router was placed, to effect connection to the new 4G radar unit and the Ethernet bus to the navigation station, secured with the power and N2K cables. Photo 11 below shows the PVC cable tube sealed in place using 3M 4200 flexible sealant. The blue spots are pieces of nitrile gloves that I unintentionally sealed in place, avoiding doing that with my hand!
Photo 11: PVC Cable Tube Sealed at Deck Photo 12: Zeus2 MFD in Place, Inside the Seaview Pod.
The second photo above shows the completed pod and MFD assembly.
What would I do differently if I were to do this again? I would install a 9” MFD, not a 12” one, and downsizing the pod accordingly. We frequently bump the pod with our calves when walking through the cockpit. While no damage has occurred and none is likely, a narrower pod would be less prone to bumping. Voyageur now has the complete B&G/Navico instrumentation package, with a Zeus2-7 MFD at the nav station, 2 Triton multipage NMEA2K displays and an autopilot commander at each helm, 4G radar, and Simrad autopilot, with the original Raymarine chartplotters, radar, instruments and autopilot retired.
Copyright 2017 Karl D. Lahm