As of 1.9, boats can no longer go "up river" at all. Instead of rising to the top of water, the boats sink and eject the player: hence, 1.9 has a "Titanic Effect" on boats. Water elevators no longer work. This makes my boat adventure in 1.9 now unplayable. This is very disappointing to me because I had made a nice boat adventure maze and was making good progress. @Quicksteve is there anyway to create a plug in for the server that would override the new 1.9 "Titanic Effect" which has completely ruined my boat adventure? Or maybe Mojang itself will do a further update, but I doubt it. They consider the boat dynamics now working as intended and the floating to the top of water as a bug which is now resolved. I may take a break from the server for awhile. Instead of inspiring me, 1.9 has ruined all my plans for boat adventures. Every boat adventure ever made can now only go "downhill" as Minecraft in general has done for me personally.
It will be at least a few months until 1.9 will get implemented on the server and in the meantime we will look at changing new behaviours to the old ones if we feel the new ones are worse, like in this case.
Awesome! Thank you very much for you help. As always, great customer service from this server. A few months from now, I will be onto my next project of a minecart maze! When the minecart falls from a height onto a flat track, you can reverse directions, so effectively have a choice of which way to go, creating the possibility for a fun maze with lots of redstone interaction.