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 |
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.
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.
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.
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.
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.
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.
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.
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.
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 hatchMost 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 bowIt 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.
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.
Not a big deal when you are doing major maintenance, but it certainly discourages a quick periodic check to make sure all is well.
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.