hitting 3 wood further than driver

I remember one time when I hit my 3 wood instead of driver, because there was water long and I know that a good drive can get there. I caught the 3 wood perfect and splash it went ... It's not the normal case for me, though. I'd say on a good hit with both clubs, the driver goes about 20 m longer in total distance. Some is just due to it running out longer, but it also gets a bit more carry than the 3 wood on a middled strike. And also, maybe because I don't use the 3-wood off the tee all that often, I feel way more confident with the driver.