The question as to how much clearance to allow when passing under power lines has come up several times in the past. I think by now we all know that there should be at least as much clearance between the highest point of the boat and the lowest line as there is between the lines themselves. That's all well and good, but standing on deck and trying to determine how much distance exists between the lowest line and the top of a mast, 50 feet or more up there, is often difficult to do with any accuracy. I might be slow, at times, but it came to me today as we past under one of those east coast 65 foot bridges that has a power line in close vicinity to it. The power line has an 85 foot clearance, a difference of 20 feet. As I think back to other bridge/power line combinations, they all seem to have the same clearance. Apparently, some wise engineer determined that 20 feet is the closest safe clearance that a vessel should have when passing under one of those power lines. Now here's the easy part, keeping that 20 foot clearance in mind, add 20 feet to the highest part of your boat and that is probably the lowest vertical clearance for any power line that you should attempt to go under. Gee, in hind sight, that seems simple enough. Guess it comes from being heeled over at 45 degrees for a tidal cycle the other day. Leaving Coral Gables, planning to head to Tarpon Bay, Key Largo, Sunday, we were up and had gotten the anchor up and housed. That was 0700. At 0705, the person at the helm who shall remain anonymous, put us hard aground about 1 hour into the ebb. So, we had a relaxing day, wedged into a settee, reading. Any movement around the boat required ice crampons and tree climbing equipment.12 hours later, magically the boat was back up-right. Yesterday, headed south in Biscayne Bay, NW wind 15 knots, clear and sunny,, south setting flood, 1-2 foot seas on our stbd quarter- a beautiful ride. Almost forgot that anonymous ran us aground. Anchored north end of one of the sounds, using the lee to help ease the winds that were 25-30. Slept good and today made it into Tarpon Bay... another nice ride with the wind and seas on our port quarter this time. Rudy and Jill Tarpon Bay, Key Largo Briney Bug- a 34 foot sail-assisted trawler 850-832-7748