United States » Forty Fathom Grotto

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Latitude: 29.28874
Longitude: -82.30895
Coordinate System:
Maximum Depth: 240'
 Cave Diving
 Cavern Diving
 Open Water Diving
40 Fathom Grotto, Hal Watt's
Date Submitter Visbility Remarks
1/15/2012 Idee B. 50' Visibility better than normal at 50'. Conducted three dives at various times of the day. Water temp at 71 deg F (consistent top to depth), surface temp 62 deg F for high, silty by evening dive, no current. Dive 1: 130' MOD, saw small plane, three cars, and a boat. Commercial diver students working in the area, so somewhat silty in certain spots. Nitrox at 29%. Strobe light on camera rig difficult to adjust for large particle silt. Dive 2: 80' MOD, dove around limestone walls, found suspended motorcycle and took a lot of photos of the bike. Found interesting ribbon of black in the limestone wall, seemed to be charred/carbon rock, on w-southwest wall of Grotto, at approx 62'. Dive 3: 60' MOD, dove around east wall of Grotto, limestone very crumbly and worn by guide ropes. Locate two caves - first with STOP traffic sign and mannequin torso secured to cave entrance. Second cave was unmarked. Entrance is on due east wall at 58', mouth is approx 5' high by 15' wide. Large oblong shaped boulder laying on its side at entrance. Limestone around entrance worn away, so may be a commonly visited cave. TOPSIDE: Now has a hot shower, gift shop. Elevator is inop, but stair and extensive decking system provide easy access in/out of sinkhole.
10/15/2010 Jason 50 What a site! The new owners have made one amazing training facility. Took some pics topside, will see if I can post them here.
9/24/2010 Ja Darr 35-50 Feet Visibility so much better than last visit (2008). Upgrades to grotto supurb. Appears to be 20-30 during the descent, but once you get to depth, you can tell it's actually a solid 40-50. If you only remember FFG as being a no-vis hole, then you need to re-visit. It's not perfect, -- a little milky, but vis is 300-500% better than it used to be. I remember it back in 2008 as a 5-10 ft vis max, but it is now greatly improved.
2/27/2010 Bert Wilcher 20 feet New upgrades to grotto are nice. entry and platforms are much better than before. Visibility still cloudy, bottom temp 58 degrees farenheit
1/31/2010 AC 15-30 Visibility varied between 15 and 30 ft down to 130 ft. They are installing a couple more platforms, one with a bullseye to signal an opening for shooting lift bags. Temp varied between 68 and 64. Fantastic dive.
5/30/2009 trimixdiverholiday 35 Good dive to 200' then around the wall going up.Shot some video.TDT=89min. Things are looking up at this site. Nice staff.
8/31/2008 karst.window 1-2 feet Vis 1-2 feet down to atleast 100 feet. One of the guides dove it 8/29 and it was clear below 100 feet. Give them a call before planning to head that way.
2/1/2008 Admin Unknown Rebecca Harden expired in the system
9/19/2007 Bert Wilcher 30 feet Visibility was much improved over our last visit. New docks and reconditioned platforms are great. Visibility was over thirty feet down to 140 ffw.
2/23/2007 Bert Wilcher 15 feet Visability has drop considerably since our last trip, blame it on the latest storm, but the vis is ok above 60 feet and very marginal below.
12/21/2006 Ben Wilcher 50-60 The best viz at Hal's I have ever seen. They put in a new motorcycle.
8/14/2006 Bert Wilcher 15 Cold on the bottom. Vis in the top 20 feet about 10'. Water clears to 30' of vis between 30' and 120'. Water clouds again below 120' and drops to 5' at 200' or below.
8/7/2006 Jim Wyatt 15 Vis was 15-20 feet at 190 feet.
2/22/2006 Jim Wyatt 40-50 Good vis at 165 feet.
2/19/2006 Jim Wyatt 20-40 feet Conducting dives to 165 feet for trimix training today. Visibility at 165 feet was 20-30 feet. Water temp was 64 F.
Click here if you would like to contribute any information or resources for this system.
Description Type Date Author Remarks
 Cutaway Map
 Home Page Web Site
 System Map Map
 System Map (New) PDF 2007 Commercial Diving Academy
 Video YouTube 2009 ClearVisProductions
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