Welcome to the boat mate.
and a very good gaming choice.
Webster has a mod that fixes most, not all, of the small remaining bugs.
It's called Game Fix Only. GFO plays only on stock 1.5, doesn't change gameplay or graphics. Might give this a try for a time to get the hang of SH4. You can add an environmental mod at this time, there are several.
The big supermods add environmental mods, improve game play and in the case of TMO increase the difficulty. TMO1.9 is the newest and is really for the more experienced SH4 player.
There is a TMOwtw (with training wheels) based on TMO1.5 easier to play and would be a good place to start with mods.
Read Fleetboats is also and very good mod, much improved graphics and a little bit easier than TMO.
You can find all the mods in the Fleetboat mods workshop. Here:
http://www.subsim.com/radioroom/forumdisplay.php?f=219
Magic