Use NOAA Chart 11411.
This bridge has a closed vertical clearance of 25 feet, with 89 feet of horizontal clearance in the center span. Approaching from the south, flashing green 9 and red daybeacon 10 mark the bend north toward the bridge, while southbound boaters will want to keep an eye out for flashing green 13.
Located at Gulf Intracoastal Waterway Mile Marker 122.7, the Welch Causeway Bascule Bridge is situated just two miles north of Johns Pass, and links Madiera Beach with the mainland at Sand Key
This bridge operates on a restricted schedule on weekends and Federal holidays. During those times, from 9:30 a.m. to 6 p.m., the bridge opens on the hour, and every 20 minutes thereafter.
Depending on schedule, the bridge can be opened by horn signal (one long, one short) or by hailing the bridge tender on VHF Channel 09. (All bridges in the state of Florida must be hailed on VHF Channel 09.)