SY has stripes on the sides.

SY is darker than Yammy :D

I don't really find it difficult to identify any ship in the game. The Yammy has light greenish/blue on the bow and stern. The SY has bright forrest green instead ont he bow, stern, and sides of the hull. Biggest thing I look for is that color difference. The SY's hull is bright forrest green, where the Yammy's is silver/gray. Big hint.

The SY has green bits of camouflage which partly cover the deck, and which you can see on the sides of the superstructure even if the angle is head on. Also, if he's running in a straight line he's a noob anyway, you should watch him turn because he should be zig-zagging.

But yes the SY should basically have a green deck front and back, the Yammy is silver.

I never had a problem myself, but if you REALLY can't tell I recommend getting some modded sprites. I used this site for some just to make other ships look cooler:

http://s15.zetaboards.com/NGP/forum/3017545/

in the IJN section under BB there are some Darker Yammy and SY sprites that should solve your identification problem. Pick one you like that's different enough and just change it.

I rely heavily on damage point numbers at the start to recognize ship tiers, personally.

If it starts with 26k DP, it's the Yamato. If it looks like it's got more than 30k, definitely SY.

you can use the ranking medal sometimes

if 3 gold bar or no medal, then BO lvl < 100, thus Yammy

if bronze medal, than could be high lvl yammy or low lvl SY

if silver or gold medal, then most likely SY or rarely a formidable player with high lvl crew back on Yammy

I usually dont judge players based on lvl or win percentage since there are low lvl prodigies / ebve as well as BB5/6 who cant aim for beans but it provides a first impression.

SY is a bit bigger than Yamato also.