From Fly-Low magazine a few months back
The Misunderstood CROSS -OVER -CABLE:
Alex Clark , Alaskan CFI
Most non-floatplane pilots { Seaplane to the lower 48 folks } and even some SES rated pilots have questions about the various parts and pieces that convert a landplane into a seaplane.
One such bit of gear is the Cross-Over cable. This is usually a tight strand of control cable stretched between the noses (maybe bows while on the water) of the two floats.
As the name implies, the main purpose is to let a pilot tight-rope walk from one side of the aircraft to the other. Something that is very handy when flying a Super Cub, Husky or Citabria with a door on only one side. On larger aircraft with doors on both sides it still helps old pilots like myself who might have accidentally exceeded our original gross weight at the buffet table. I have seen videos of myself trying to cross over two interior seats in a big hurry. It is not a pretty sight.
However, I have had occasion to run into floatplane pilots who intentionally do not install cross over cables because they think they are unsightly. My answer to that remark is that the cable does much more than allow the pilot to practice a circus act above deep water. So I made up a short list of attributes.
1. The tight cable acts like a bumper to protect your propeller. Tree stumps, pier pilings, brush and tall grass will be deflected by the cable before any offending object hits the prop. Personally I have bounced more than one seaplane off of old dock pilings.
2. Plus a tight cross-over cable gives you another reference to bore-sight your float's spreader bars. If the cable, and both spreaders are all level with each other, your floats will be usually happy campers and will take-off faster and fly straighter.
3. You can stand centered on the cable, hold the prop hub and lean backwards to take weight off the rear (aft) section of the floats when you are heel-beached. ( beached with the after section of the floats up on the sand )
The cable gives you another place to balance a piece of plywood with engine maintenance and oil changes. I put one end of the board on the spreader bars and another over the cable. It gives you a platform for your used-oil jug and when you drop your best socket wrench, you can watch it roll for a few feet before dropping into deep leach filled water.
It makes the preflight inspection faster and more complete. It gives you access to the propeller and forward cowling.
Walking across the cable is not very difficult as long as you remember to keep one hand on the propeller spinner. And remember that if you do slip off for some reason, to make sure both legs go over the same side of the cable. There is a video someplace of myself doing the splits right onto the cable just before I fell into a ice cold mountain lake. In that case the icy water was of some benefit.