Florida
M2 Blue (Fannell's Funnel)
Info · exploration
Information only: an exploration project of Karst Underwater Research (KUR) under water district land in Twin Rivers State Forest and private land. We found no public arrangement for divers.
- Max depth49 m (161 ft)
- CertificationFull cave
- SpecialExperienced divers
Diving and fills
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Fills nearby
- Extreme Exposure (High Springs)Air, nitrox (32 %, 50 %), O₂ (AL40) and trimix ('mix' in doubles); walk-in fills of your own tanks: ask
- Cave Country Dive Shop (High Springs)Air, nitrox 32 % and 50 %, O₂, helium; trimix 21/35, 18/45, 10/70 and custom; CCR O₂ fills
- Ginnie Springs dive shopAir (high-volume) and nitrox 32 %; no trimix listed. Prices 2026, excluding tax: air $9, doubles air $14, nitrox single cylinder $15, nitrox $0.15 per cubic foot (for top-offs and doubles)
Now at M2 Blue (Fannell's Funnel)
The dive
The upstream section is shallow and clear, but beyond a breakdown room where at least four passages meet, a large siphon passage runs south at 46 to 49 m.
Profile and sections
The upstream section is shallow and clear, but beyond a breakdown room where at least four passages meet, a large siphon passage runs south at 46 to 49 m. The cave water is 20 to 21 °C all year; the river ranges from around 10 °C in winter to nearly 30 °C in summer, and that is where you do most of your decompression.
Buford Pruitt discovered the cave in the early 1990s and explored it with Mark Long and Fred Davis. In 2010 KUR cleared the M2 Blue entrance and connected the system with the old line of Fannell's Funnel. Brett Hemphill, Andrew Pitkin and Michael Poucher laid ~1.4 km of line at ~47 m in the deep siphon; in 2015 Andrew Pitkin and Charlie Roberson pushed the Prehistoric Tunnel to ~3.5 km from Fannell's Funnel, towards Madison Blue Spring.
Practical: information only.
- Depth and profile
- Plan for ~-49 m: the deep siphon lies at ~-46 to -49 m (KUR's fact box gives max -43 m), ~1.4 km of line at ~-47 m; the rest ~-30 to -37 m · ~5 km surveyed
- Configuration
- No configuration rules published. Decompression of more than six hours, largely in river water.
- DPV: unknown
- No scooter rules published.
Who can dive where
- At least Full cave
- Configurations: Backmount / twinset / Sidemount / CCR / Small cylinders / no-mount (speleo sumps)
- Configuration unknown — research beforehand
- Goes down to 49 m (trimix or deco may be needed)
- Experienced divers only
This is how the planner decides who in your team may dive this cave. Rules your own trip adds (organizer, a mail, the AI) show with your trip.
How to get there
On the Withlacoochee in Madison County (the cave also runs under Hamilton County). The Fannell's Funnel entrance lies in the river. KUR explores here only in summer; in March 2024 the water was too high to dive.
Around M2 Blue (Fannell's Funnel)
Fills3 fill stations · nearest 0 km
Extreme Exposure (High Springs)
18481 High Springs Main Street, High Springs, FL 32643
Air, nitrox (32 %, 50 %), O₂ (AL40) and trimix ('mix' in doubles); walk-in fills of your own tanks: ask
Daily 8:00–18:00
Tech and cave shop since 1995. Rents singles, stages and doubles (steel/alu, air, nitrox or mix), regulators, backplate/wing, lights and scooters; training.
Cave Country Dive Shop (High Springs)
19808 N US Hwy 441, High Springs, FL 32643
Air, nitrox 32 % and 50 %, O₂, helium; trimix 21/35, 18/45, 10/70 and custom; CCR O₂ fills
Daily 7:00–19:00
Prices per cu ft online (e.g. 18/45 $2.04, 10/70 $3.15, O₂ $0.50; CCR O₂ min. $6). Rentals: backmount/sidemount doubles $14/day, trimix bailout cylinder $16, SUEX scooter $85/day, Shearwater computers. Cave courses from cavern to full cave and CCR cave (TDI, IANTD, NSS-CDS) by the owner's BJL Diving, and guided cave and spring dives, also with scooter, CCR, trimix and stages.
Ginnie Springs dive shop
Ginnie Springs Outdoors (in the park), near High Springs, FL
Air (high-volume) and nitrox 32 %; no trimix listed. Prices 2026, excluding tax: air $9, doubles air $14, nitrox single cylinder $15, nitrox $0.15 per cubic foot (for top-offs and doubles)
Park hours: Mon–Thu 8:00–17:00, Fri–Sat 8:00–19:00, Sun 8:00–18:00. Last fill between 15:00 and 17:00, depending on the fill technician's availability
Rents cylinders (incl. nitrox steel 85), BCs, regulators, suits and lights. Personal compressors are banned in the park.
Drive times from High Springs: we don't know this site's exact spot.
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