I was on a newr iver this past weekend that had many large open flats with less than 2ft. of water. Since I didn't know the river very well, I idled through these areas. I'm not used to being on water with large super shallow flats like that. I did see a couple nice bass boats coming out of the deeper channel and flying right over these shallow flats though.

So, my question is, for an average bass boat, how shallow can the water be to be able to pass over it while on plane??

Go out with a tape measure and see how much you draft when sitting. You can do this by measuring from the waterline to the ground, then measure from the bottom of the outboard to the ground and subract that number from the first number. This will tell you how much water you need to float without raising the motor. You can measure from the bottom of the hull to see how much you draft with the motor raised also.

To get an idea how much you draft when on plane, you need to have an idea where your waterline is when on plane. You can do the same measurements in your driveway to get an idea how low your outdrive is when on plane.

I have a deep V center console 'Bay boat' and my draft is about 24" sitting and about 18" on plane. Most bass boats will draft less than that.

Thanks for the tip Skwerl!

I made the mistake of taking my bass boat to the coast a few times and was running along and came up on some shallow sand flats... (realizing it was too late to shut down)  I trimmed it up higher and went to full throttle to get as much of the boat and motor out of the water as I could... I made it but lost a little paint on the skeg.  I waded back later (chasing some reds) to find I had run through about 14" of water.  Never made that mistake again but I learned that with 16"-17"" my skeg would have cleared.

I gave a quick prayer of thanks and a nod to the sky after reaching deeper water that afternoon.  

I hate running shallow water, just because you never know what could be on the bottom... a single rock or log, etc. could ruin your boat or WORSE, kill you if your boat comes to a halt.  You used good judgement, since you were unfamiliar with the water, I applaud you for not just following them out.  

Stay safe and have fun!!

My custom prop cost approx $1000, my lower unit cost approx $3,000, I don't carry insurance so it's gonna have to be at least 5' or more for me to keep on plane.  That's in water I'm familiar with.