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Installation Design

Anatomy of a good VSAT or TV installation | Below-Deck Equipment Rack Access | Nothing beats an open rack with rear and side access. | The best rack installations allow front and rear access without tools. | Rolling racks require rails installed | Rotating racks are a good compromise. | Rittal front door equipment mount. | Service loops allow live equipment removal. | Mount TV decoders vertical to save space | Minimal Tie wraps | Label cable ends in plain English. | Operator equipment at eye level | Antenna placement with safe and convenient access. | Stub Mast for hatch clearance | Side radome hatches | Rigid mast mount, free of vibration | Mast height versus stability | Correct cable connectors and tools | Ventilation and Heat Disapation | Accessable Antenna Power breaker | Diagrams and Cable lists | Minimal blockage | Antenna alignment | Well Documented and simple |
After years of service calls on some of the worlds finest yachts, it amazes me how some of the best shipyards still make it so difficult to service the equipment. I believe that the installation and location of the electronics is one of the last considerations for designers and shipyards. Below-deck equipment is often delegated as an afterthought, to whatever tiny space is left over, with no consideration that the equipment will ever need maintenance in the future. 
On almost every yacht I attend, I swear that there must be a better way of mounting below deck equipment.

The equipment rack is an industry standard in offices and equipment rooms around the world, as it is in the cramped environment onboard yachts. The big difference is that in an office you have plenty of room and walk-around-access to the rear of the rack, and it is an efficient and servicable solution.

On all but the very largest yachts, the equipment racks are crammed into a closet with no access to the rear of the equipment without jumping through hoops to slide out or rotate the rack, sometimes just to access a power switch or reset button. Most of the satellite equipment is designed to to be rack mountable, and until someone comes up with a better system, we will be stuck with the rack mount solution. 
In my opinion, the best solution on any vessel is a simple, open rack, either free standing in an equipment room, or mounted through a bulkhead with cabinet access to the front of the equipment and rear and side access from within the equipment room or utility room. 
The most practical installations allow access to the front of the rack through a cabinet door, perhaps with the front of the rack facing out into a passage, with the rear of the rack facing in to a utility room. This could be a laundry room or pantry or some other crew space that will not impact guests during maintenance.

For smaller racks the bridge console provides a solution with the front of the racks facing aft alongside the helm, behind cabinet doors, and access to the rear through the crawl space behind the helm. Another possibility could be the aft bulkhead of the bridge with access to the rear through the captains office of captains cabin.

In a dedicated equipment room, the racks should be mounted with walk around space to the rear, and if possible, easy access to the side.

Racks should be as open as possible for ventilation and service access, ideally with no back or side panels, and without restrictive sides on the shelves.
Racks that roll out on rails are the most common solution on larger yachts. The heavy and sharp rack rails are normally stored away in closet and require great care not to damage varnish while transporting them to the rack. One then needs to remove rack panels to release the rack and attach the rails below the rack using several screws.

Judging by the mounting method, I believe that these rails are intended for permanent installation, and not for temporary use. On older systems the rack nuts securing the rails are often missing or stripped after years of attaching and detaching the rails. 

Often the outer edge of the rails needs to be shored up on a bridge to make them level. One then needs to release the heavy rack and carefully slide it out on the rails. Not something to be attempted in a seaway. There can be a huge amount of weight in a fully loaded rack that is now floating free. A disaster waiting to happen. 

This is a time consuming procedure if all you need to do is reset power to a piece of equipment, or check a connection, but it is the most common method in use on larger yachts today. 

Even when the racks are in the normal stowed position, it is important that they are well secured so that they do not come loose in rough weather. There is a lot of weight and inertia in a fully stocked rack.

Enough room needs to be allowed to slide the rack all the way out and provide space to crawl in behind the rack. 
 Middle Atlantic also makes a rack that slides out on permanently mounted drawer-type slides, and can then be rotated to access the rear of the rack. This is quite a good compromise, if it is well installed. Unfortunately, on most of the racks I have seen, you still need to undo screws and remove panels to release the rack from the wall. There is a lot of room for improvement for a quick release system.

To reduce weight, it is advisable to split larger racks into two 24U units stacked one above the other, separated by a shelf, rather than trying to rotate a fully loaded floor-to-ceiling 44U rack. 
On some larger yachts I have seen a large steel rack made by Rittal where the equipment mounts in a 19" frame in the front door. As the door opens, the equipment hinges out with the door for access to the rear of the equipment, and access to the bulkhead behind. 

The rack door is about 6" wider than normal, and the equipment is offset to one side to allow the rear edge ot the equipment to clear as it swings out.

This is a very practical solution if you have the room for it. 
In any rack, the cables should be left long enough so that each piece of equipment can be removed from the front of the rack while it is still connected,and even while the equipment is powered up and operating. Service loops can be kept reasonably short by leading the cables to the connectors on the rear of the equipment in a loosely tiewrapped umbilical loop from above or below and to the side of the rack. 

Many racks appear to have been assembled on the shop floor, before installation on the vessel, with everything neatly tiewrapped and not an inch of slack. This makes simple tasks almost imposible without completely removing the rack. The lack of service loop is often the cause of connectors becoming dislodged. This is particularly evident with TV decoder installations. It would make life so much easier if one could remove each device from the front of the rack, perform whatever maintenance needs to be done, and then reinstall it live in it's position in the rack. 
Most TV decoders are narrower than a 19" rack, and waste a lot of space when mounted horizontally on a shelf. The most efficient use of rack space is to mount the decoders vertically, like books in a bookshelf, allowing ventilation room for the heat to rise between and above the decoders. 

If the decoders are held in place by friction, and have a long enough service loop, they can be easily removed, one by one, from the front of the rack for maintenance purposes. 
 Cable ties should be kept to the absolute minimum required to keep the cables together or in place. Uneccesary tie wraps placed every few inches may look very neat and professional, but it makes troubleshooting down the road a nightmare. 
Unless it is obvious where a cable connects locally, and where is the distant end, cables should be clearly labelled in plain English. I have been on so many yachts where cables are cryptically labeled  something like "TA 657/29-0-G". The build engineer has long since left the vessel and a search of the plastic bins under the forepeak does not turn up the shipyard asbuilt manual. Nobody knows what the cable was for or where it goes.

It would be so useful if the label indicated where it connects, where it goes to, in a way that engineers ten years from now will understand without having to refer to some key or diagram. In some cases it would be very useful to add a second or third label indentifying the location of any junctions along the cable run.

Professional printed labels are so much better than the hand scrawled, smudged ball point ink lables that one still finds occasionaly, even on recent newbuilds, although even a magic marker felt pen label is better than no label at all. 

One well found vessel I was on recently had a fully detailed, laminated wiring diagram attached inside the rack door, which was extremely helpful.

Equipment that requires the operator to routinely read the screen or push buttons should be mounted as close as posible to eye level. I have seen many installations where idle equipment like receivers and modems that require no user input, take up the prime rack space and the antenna contoller is delegated to the bottom of the rack. 
Understandably, the highest priority for antenna placement on yachts, is the aesthetics of the lines of the vessel, but often, little provision is made for safe and convenient access for service.

In my experience, antennas that are easy to access tend to be well maintained, whereas those with restricted or unsafe access often have ongoing problems.

If the vessels crew, or service technicians have quick and easy access, they will not hesitate to go the extra mile to ensure ongoing reliable operation. If access to the antenna requires a special 20 foot ladder that is stored somewhere on shore, or removal of the radome, or some heroic acrobatics or contortions to access the hatch, simple routine maintenance tasks become a major event, best postponed until the next yard period, or perhaps completely neglected. 

Safe access to the antenna hatch

Most antennas are mounted with the radome hatch facing aft. This makes sense, as it reduces the risk of wind driven water entering the hatch seals when the vessel is underway, and avoids wind interferrence at anchor, while the hatch is open during maintenance. These advantages are negated, if it makes access to the antenna impossible without the use of a very long ladder, which is rarely available onboard, unless you are in a shipyard.

Access hatch option to the side or to the bow

It is very easy to mount the radome base with the hatch to one side or the other, or even facing forward, if this provides safer access. The proposed antenna placement on the right would need a forward or sideways facing hatch, or a very long ladder if the hatch was placed aft.  In this case, a forward facing hatch provides a safe, secure platform to stand on while accessing the hatch. 

The home flag adjustment, that aligns the antenna with the bow of the boat, can easily compensate for the orientation of the hatch. Many captains have balked at this suggestion, saying that it would not look right with the hatch on the side, or to the front, but when the hatch is closed few people will even notice it. 
Another common error is to mount the antenna directly to a mast platform, deck  or cabin top, allowing only inches between the hatch and the base, limiting access to the antenna for all but the most agile and underfed technicians.

With the antenna mounted flat on the deck, I am usually able to get just my head, one shoulder and one arm into the radome, and with a lot of contortions I can get both arms in, and sit up facing the wrong way. Not a good solution, especially when you need to reinitialize the antenna and let it rotate while you are stuck inside the hatch.

On the top of a mast this limited hatch access is both dangerous and almost impossible, requiring the radome top cover to be removed from the antenna, even for a simple repair. 

A short, 6 inch stub mast placed between the base of the radome and the deck would make all the difference, allowing easy access for personnel. 

Sometimes there is no choice but to have hatches installed in the side of the radome. While these do provide good access, it is difficult to ensure water tightness, and you often need to remove a dozen or more screws each time you access the antenna.

Not a big deal when you are doing major maintenance, but it certainly discourages a quick periodic check to make sure all is well. 
It goes without saying that the antenna needs to be mounted to a solid surface, but I have seen a few antennas that have been destroyed by vibration and by mast failure. 

In one case, after a relatively smooth transatlantic crossing, the vibration caused by the vessels movement through the water caused the wire rope isolators at the base of the antenna to completely disintegrate, causing irreparable damage the antenna when the base collapsed. The antenna mast appeared strong enough, but if you shook the antenna fore and aft, it would set up violent oscillations that work-hardened the wire rope and caused it to break during the 20 day crossing. The mast was not rigid enough fore and aft, and after replacing the antenna, this particular mast actually failed completely.
 It is often tempting to raise the height of the antenna mast or to place the antenna at the highest point on the ship to avoid blockage and improve line of sight to the satellite, but this comes with the cost of stability, vibration and the the detrimental movement during rough weather. It is often better to live with some blockage and keep the antenna closer to the waterline and the center of the ship's movement.
Blockage zones. One zone.