It may not really be your employer at all, but the policies of their contracted shipping company. I've had many experiences moving household goods at my employers expense and it always came down to what the moving company would except. For a time I was able to ship any type of boat; 18' sea kayaks, 18.5' flatwater racing canoes, and whitewater boats.
Unfortunately all these types of boats require special handling. Most companies I've shipped household goods with arrive at the house with a moving van, which is loaded with the boxed belongings, it is then transported to a shipping warehose where all the stuff is transfered to the appropriate sized intermodal shipping container. It is much more complicated then just throwing your surf ski into a container. It has to be wrapped and padded, sometimes by people who really don't care all that much. Plus the potential for costly damage claims is a concern.
Eventually a length limit of 14' was set, that basically left whitewater boats and surfboards being the only watercraft excepted for shipment. No more long boats. Oddly enough, if I wanted to ship a motor home or power boat on a trailer it was Ok, go figure.
Whatever works out, good luck and hope for a damage free shipment.