The Sea Turtle mount is supposed to go the same speed as a normal speed land mount (160%) while it’s in water. Currently it only goes 108% speed because its +60% swim speed buff is being negated by the inherent 0.66 speed decrease of water.
Doing a “.list auras” while mounted on the Sea Turtle shows that it has two auras. One with amount 0, and another of type 58 (HandleAuraModIncreaseSwimSpeed in SpellAuraEffects.cpp) with amount 60. I guess the first aura is for when it’s on land, and the second for when it’s in water. It seems like all one would have to do is increase the 2nd aura’s “amount” to 142 (the hacky way), or somehow make the mount immune to the water speed decrease. How can it be done?
http://old.wowhead.com/spell=64731
EDIT: Thanks to whoever edited my post to include a link to the Sea Turtle mount spell. I’d also like to include a link to the item ID http://old.wowhead.com/item=46109 , as it has some relevant information in the comments (including testimonials that it does, in fact, go 160% in water)
EDIT2: It’s looking more and more like I’ll either have to make a 3rd aura that enhances the 2nd, or make a custom script that increases swim speed while mounted on the turtle. Is there a more elegant way to fix this? It seems like the retail Sea Turtle is just immune to water speed decreases… somehow…