We eventually spend two nights in Manatee Pocket - weather is dreadful. Winds picked up on the first night and howled through the rigging in the early hours - a loose halliard was thwacking against the mast but neither one of us was offering to go out in the torrential rain to silence it - at least there were no other boats who would be bothered by it.

In the 'old' days a coin would have been tossed to find a volunteer - then, on with oilies and so'wester, the poor soul would crawl along the deck on hands and knees toward the offending noise clutching a bungee to deal with the thing - I just refuse to do it any more!!

We depart Manatee Pocket by 10.00 am - it's a rough day on the intracoastal - over the VHF the Coast Guard repeat their small craft advisory warning for offshore boating and tell us to expect a 'light chop' on the waterway.

We have about 12 opening bridges to negotiate today. Only two of them open on request - the others have odd times like the hour and the half hour, or quarter past and quarter to the hour, and one opens every 20 minutes.

Detailed timing of waypoints is vital so as not to miss an opening and this is easily done with the electronic charts - we either slow down or speed up depending on the predicted ETA at each bridge. The Bridge Tenders stick rigidly to the rules.

After our penultimate bridge of the day we come into the top end of Lake Worth, north of the atlantic inlet, and are surprised just how lumpy it had suddenly become. Added to that a passing series of motor yachts surge past us at high speed - their wake causing us to heel heavily side to side.

Our anchorage is beyond the next bridge (Riviera Beach Bridge) which should be at least 65ft clearance at high water. We stop in our tracks as we approach it - we are just below high water and through the binoculars I can see that the panel is showing only 63ft!!! - we need 63.5 ft.

Those of you who know William well have already predicted the next move - we are going to TRY IT - not totally foolhardy, as Alexia has a secret low-bridge detector! It is 24" rod at the top of the mast projecting forward on to which is mounted an 18" false aerial topped with a small fishing float. This aerial is marginally higher than all the breakable sensors at the top of the mast -if the float touches the bridge we don't go under.

Several things are also now in our favour - the choppy water is less churned up near the bridge, the tide is against us and boat traffic has reduced. I sit at the bow looking upward as William creeps forward very, very slowly - as the float reaches the underside of the bridge I waive frantically - we are clear.