Well, half of them are on the bottom of the ocean already...Curious how the New Britain campaign is going.
I wonder, where are the Japanese Kongou-class battlecruisers? They sound like the best option for dealing with British cruisers harassing the convoys.
Hiei is still undergoing her reconstruction and won't be recommissioned for some time.
That just leaves Kongo, which as Japan's only fast BB at this point is being held in reserve.
Fortunately (for them) Japan's super dreadnoughts are still fast enough to escort even a "fast" convoy. May not be fast enough to chase down the pesky cruisers, but eh as long as the convoys are getting through that last bit doesn't really matter.