Surf Launch with a Fish Finder

[Molten Furnace]

I just had a fish finder installed on my kayak and I am excited to try it out tomorrow in La Jolla. I have seen some guys that put plastic bags over their fish finders when launching and landing. Is this the best practice? Someone else told me to disconnect the unit and store it in a waterproof pouch during launch and landing and then connect it again when beyond the breakers. That seems like a hassle to me and with my luck I might flip the whole kayak trying to connect the unit once I'm at sea. Any suggestions?

Thanks!