[LucillusTaylor]

So the game lags every single time I drive a boat or swim on water. It works for a few seconds but has occasional lag spikes and can be choppy how can I fix this?

[VeryTallMidget]

If you dont swim(just float in water) or stop the boat, then its not lagging ?
if so then its the water spray effect making this lag.
I would start from any kind of video settings, change something or turn something on or off and go check if it had an effect on lag.

[PgMNA]

make sure you are not using any kind of cleo/mod