Yes, there is a way you can take boats from RA2 and put them in TS. However! By doing so you will have to include the following with your map. Voxel file and HVA files of the boats you add, an edited rules.ini and an edited art.ini that include the boats you add.
Personally, by doing that you would A) Take a lot of time getting the boats in-game and set on your map. and

Less people will be likely to download your map and the other contents due to some people don't like having edited rules.ini as it messes with online games and other such stuff.
It is really a long, kinda boring, process. I am pretty sure there are tutorials already around the forum and at ppmsite.com that can tell you just how to do what you want.
Anyways best of luck to you with this. I may or may not try your map out once it is finished.