Help adding a speed boost when in water

[chimera27]

I have been trying to add some kind of potion effect to be applied when the player is in water, they get a speed boost, but apparently vanilla speed has no effect when the player is in water. I looked in the potion class to see how the vanilla speed did it butt the only thing I found was:

.func_111184_a(SharedMonsterAttributes.field_111263_d, "91AEAA56-376B-4498-935B-2F7F68070635", 0.20000000298023224D, 2);

Which I have no idea how it works or what it does.

Does anyone know how to make a custom effect that simply increases the players speed?

[Mazetar]

Maybe the beacon block could give some insight, it gives a speed boost?

[chimera27]

It just adds the speed boost buff, which does nothing while you are in water anyway. I am trying to make a buff that acts like speed but is not nullified by water, but I have no idea how to do that because the actual way that speed does this is not plainly visible anywhere.