Sunday, January 13, 2013

Cockpit TV under the arch

It seems fitting to start at the end of the project. We now have a arch mounted TV that looks good when stowed, and yet has a huge range of motion. This is a 28' footish cruiser, and the cockpit functions as the owners main salon. Watching TV before required, as the owner stated, "You had to go down into the dark, and watch it from the bed."

There are a number of primary considerations to be aware of to make all of this work well. The TV should be thin.  LED versions work best, and are lighter. For reasons I will touch on, the selection of the right mount is critical. And lastly getting the support infrastructure in the right place is very important.

Size does matter in your TV choice. Our mount's arm has a maximum reach of just over 15". In order to be able to swing the TV out, and rotate it 90 degrees, the width of the TV can't be more than 30", and a bit less is better. The TV we selected is a 24" LG LED that spatially scales nicely with the environment.

The first thing about a boat's arch is nothing is square. It's angling slightly inward, and is twisted a bit relative to the longitudinal axis of the boat. All of this gets worse the higher up the arch you place the mount. Translated clearly, if the TV can't rotate about the end of the mount arm, things will get real wonky fast.

If the TV looks nice and square when stowed, it will be slightly twisted when deployed. So you need the end of arm rotation to make the TV look good to you no matter where it's located. I have grossly exaggerated this in the photo, which also demonstrates the wide range of motion this mount is capable of. 

Now for the nitty gritty. Two thing should be done first. Installing the cabling for the TV's signal, and mounting the TV. I have shown in the photo the approximate mount location. In deciding on the mounts location, you have to remember that nuts go on the bolts. To do this you have to get your hand inside the arch.

If I had wanted the TV to be mounted higher, I would have, and have done in some cases installed Beckson plates for access.

You also have to keep in mind that some infrastructure is needed in the area behind the set such as power, and a outlet for the TV's signal.

You should temporarily fit the TV and mount first, and check for the mount's swing arm clearances before you cut holes for the outlet, and cable plates. This insures that you don't have a "D'oh" moment when you discover the arm is going to hit something that plugs into an outlet.

The cable and power outlets can be bought at almost all hardware type stores. Doing the cable outlet just required drilling a 3/4" hole and a couple of screws. The GFI outlet however is a little more tedious.

In this case I didn't really need a GFI, but the cover plate itself had a little additional depth. You can't use a traditional outlet box because there isn't enough depth in the arch. Cut the hole, and screw the outlet to the arch using the two end tabs. The cover then gets screwed onto the arch. Don't forget to wrap the edges of the outlet with electrical tape. You don't want to be jolted if your fingers find exposed terminals. In this case power came from the outlet in a cabinet just below the TV.                   

Like all things on a boat, there will be a myriad of minor surprises. The universal TV mounting plates can and often do cover places you need to plug things into especially on the smaller sets. This mount comes with shims to push the mounting plate away from the back of the set about an inch. They were needed. It was enough to allow the power plug to fit. Often RCA plug sockets can get covered up also. The fix to this is ninety degree adapter plugs.

This boat only had one TV so its system was simple. All I had to do was to add a splitter to the output of the Glomex box to add the second set. In boat with more than one TV there will be a splitter block already installed. If there isn't any room for the new TV, you will need to buy a splitter with more outlets. If you try to add a splitter in front of the existing one, you can end up with a lot of signal loss.

This project took about six hours to do and it also included a previously discussed, irritating NMEA VHF interface. The mount can be loosened or tightened with an allen wrench. You will have to play with the stiffness until you get it where you want it. During rocking and rolling travel it would be wise to restrain the set with a bungee cord or the ilk. Removing one bolt and a snatching the plugs, allows the set to be pulled and stowed below. Now go watch the idiot box, the cartoons are on.

The mount for this project was a Sanus MF 215, and the dimensional sketch came from their website.


  1. I've got a couple of tricks up my sleeve that you might find useful.

    Clock-hanger outlets can be used on installations when a wall wart isn't used. Sometimes they allow a flat panel to sit closer to the wall.

    There are also low profile gfci outlets available now that will fit into shallower boxes than a traditional gfci. I've seen them in big box stores so they shouldn't be that hard to find.

    Finally the Carlon B117RSW is an electrical box that can be a real problem solver when you need volume but are limited by depth.