United States » Hudson Grotto

  • Currently 2.9/5 Stars.
  • 1
  • 2
  • 3
  • 4
  • 5

Rated 2.9/5 stars (338 ratings)

Overview Location & Specifics Conditions Resources Nearby Systems  
Hudson Grotto is primarilly used for open water training and is also available for private parties and special events. The Grotto walls are hour glass shaped loaded with solution tubes and other objects to look at. The bottom is dome shaped, and the edges average around 100'-110' feet with the deepest spot being about 155'. This spot is a small opening against the north wall. There are four platforms, three of them just under the end edge of the dock, and one in the middle of the sink. The three platforms are layered like steps, the first one is at 20', the second at 45' and the third at 60'. Tied to the white barrel there is a line that runs down to a 100' platform which is used for Advance Open Water classes. The platform sits next to two boats and lines run to an old VW van, and other interesting objects sitting on the bottom. There are several thermoclines, the mid-water temperature can get pretty cold between 40' and 80'. However the bottom temperature usually stays in the low 70's. The water is tannic all year and visibility fluctuates with the algae bloom. Cost is usually around $10-$20 per diver depending on visibility.
Click the map below for all mapping options.
Click to View Larger Map
Latitude: 28.34564
Longitude: -82.70125
Coordinate System:
Maximum Depth: 110'
 Cave Diving
 Cavern Diving
 Open Water Diving
Date Submitter Visbility Remarks
10/30/2021 Keith Blair 5' The water levels were pretty high (level with the beginning of the dock) and the water has been pretty dark for a few months now. The buoys and platforms have been rearranged. The 25' platform is still just off the dock but the 60' and 100' platforms are now on the far side of the grotto (there are 4 white buoys for the 60' platform and a single white buoy with 100' written on it for the 100' platform. The original boat at 30' is also on the far side, marked with blue buoys slightly to the left. Within the last couple of days they added a new boat at around 60 ft deep which is just to the right of the dock. It's a similar style boat as the original 30' one. It was 65 degrees outside and the water temperature was 79 degrees. While Hudson Grotto is really dark, it's a very easy dive and it's fun finding all the hidden treasures in the walls.
6/12/2014 J Keller 4' Clear day. Haad 2 groups of students go in to the 25' platform. At 45' it is a little better vis but still has silt floating around. Very warm water till you hit 70' then starts getting colder. Small Barracuda in the area, very strange to see, kinda startled me. Water cleared up a bit around 90' but need lights to see as water above blocks it out. temp was 68f @ 95'. Planning on going back out to test new light. They did sink the boat that was near the waters edge after my trip. They are also doing a siphon of the silt to make it better.
1/20/2013 Tyler King <10' My buddy and I had the hole to ourselves on Sunday. Dropped the main line to the 100' platform to find viz no better than what our lights could provide. Found the line to the VW bus then went up the wall to the 60' line and circled the hole and went up from there. Temps were in the low 60's but hit some thermoclines that felt colder. Water was tannic as expected which further reduced viz. All in all, interesting dive worth trying if you don't mind the cold and darkness.
2/23/2011 Bert wilcher 20 feet tannic but clear, temperature 60 degrees farenheit.
11/28/2010 Jason 10' Could not see 22' platform until we were almost on it. Missed the 60 ' platform all together. Water temperature was mid 70's down to 50 ft or so, then it dropped in to the 60's. Would have been a nicer dive with better vis, but I have fun anyways.
7/10/2010 Darwin Coiner 20-30 ft Scuba West let everybody dive free today and had hotdogs and hambergers fresh off the grill. And for the first time in awhile the viz was pretty damn good, water temp was 84 till you hit 45 ft then dropped to 71 and then dropped again at 80ft to 66. Over all good dive .
6/6/2010 Darwin Coiner 15-25' Water was warm about 83 degrees, untill 40' then dropped quickly to 71 degrees. Viz was not as bad as I have seen it but not great either . Planned to go to the bottom to check out the vans but had a problem clearing my ears. Sorry Randy and Jack, mabey next time.
6/28/2009 Buhlz grotto Kev and I dropped a new camode down there today. Just SE of the large PVC toward the vent @ 115 feet. Interesting dive
5/18/2009 Trogloxene 25ft A lot of students were there today so the visibility was bad up top. I did two dives with TMet. Our 1st dive was a descent to the 100' platform. We followed the various lines to the boat and vans. We ascended to 60' and did one lap around the grotto. The 2nd dive we descended the gold line to 85' and hit the halocline. We ascended a few feet and then did a nice dive under the neck of the grotto. The visibility was very good under the neck and our lights (Salvo & Diverite) provided good illumination against the wall and the ceiling. The 2nd dive was probably one of the better dives I have had at the grotto, the other was the time I dove with Kevin and Kyle to 130' and saw the entrance to the cave. I hit a few spots where my computer read 64 degress. Both of our dives were within NDL and followed by a 3 minute safety stop.
5/3/2009 Buhlz 30 Met up w/ Kev and Alicia late but Stan and I did a spurtofthemoment dive. Stan's last dive was 3 months ago so we took it easy checking out the vans,boats, and other goodies. VERY cold between 45' - 90'.around 67 degrees so if you're planning that depth for a while, you might wanna think about dryness. 65 min 21%, 14min deco.
12/20/2008 Buhlz 40' above sulfer layer Well, I don't seem to give 'the Grotto' enough credit nor have I posted on this site but been here several times. I assisted Kev S. installing line arrows to guide people to the wonderful things that lie below. Pretty cold in there today w/ 66 degrees aboive 35' and below was around 72-74'. Everything went well, though staying at 110' for 40 minutes adds too much deco to be cold to deal with so we shall return. Thank you Scuba West for everything guys: we do appreciate ya! Total: 45 min 110' 14 mnin deco- 21% no O2
11/23/2008 Fed 2-5ft Dove down to 106ft along the guide lines, viz was terrible no more than 3feet your light. Did a second shallower dive to 60 feet, viz was maybe 5-10feet tops. Not worth diving in my opinion. I wont be coming back.
5/1/2008 JCH 5-10' Nice long dive spiraling around the wall down to 110'. Tied a line and went in the hole to 146' but vis was terrible, even without silting up the place. Temp was 79 at the surface and once through the thermocline and halocline 73 at 110'. Hudson is really one of the best sinks for training, checking out gear, etc. Great people at Scuba West as well. Tried out the new 50w Salvo and the bubble watcher said she could see the glow in the water (when above the halocline). We had two of them in there and they are some light. Impressive - great job Slavo!
8/11/2007 Chris Krier 15 ft Vis is a poor at around 15 ft with lots of particulate debris in the water. Surface to around 20 ft is nice and hot around 89 degrees, then drops off sharply to around 66 according to my computer. Water level is up due to recent rains.
1/7/2007 Chris Krier 15-17 Water temp at the surface is a chilly 67 degrees. Vis isn't bad. Temp actually increases below the halocline. Lots of particulate matter in the water. Created a good deal of backscatter with our 10watt lights. As always a great place to dive for practice and we will continue to dive there.
11/19/2006 Frank Lavallee 50'-60' The water temperature was 70 - 72 degrees from top to bottom. There was a milky hydrogen sulfide layer between 70' - 90'. The water was its usual tannic color, and daylight was lost at 50' - 60'. Visibility at depth was 10' or less.

Several open water classes and other training classes were in progress, so there was a lot of diver traffic. The saltwater intrusion is taking its toll on the platform, vans, and boats on the bottom at 100' - 110'. Any metal that you touch with bare hands will stain them black.
9/26/2006 Dan Duchesneau 10-15 I Love this dive. I have done this dive several times. The bottom on this dive on outskirts of the sink is around 130 -135 feet but on a heading of 150 deg where the wall meets the floor there is a hole in the floor that drops to at least 146 feet (if you wanted to go into the silt a bit it would max about 150 -152). There is enough room for 2 people on a tight squeeze. be careful the inner wall (closest to the center) looks like stone but it is actually a clay that will silt up the hole in a heartbeat so I would keep off of it. once in the hole there is little room to look around but not much. I love this dive and will be back again soon.
8/15/2006 allen jonovitch 20ft very nice dive, I've done this dive 4 separate days over the last month for fun and also my IANTD deep class. at 20-40 feet vis was about 25 feet once u hit 70 the sulfur cloud was their and vis dropped to about 5-10 feet. at 100-120 feet vis dropped to about 6-7 feet max with 10watt light. very nice dive overall just remember at 110 feet to practice that frog kick otherwise the place gets silted out VERY easily
6/11/2006 Chris Krier 20 ft The water temp was nice and up in the 70's at the surface, at 20 ft, and out over the 45 ft platform, the temp dropped significantly, down to the mid 60's and was quite interesting. The halocline was present below 80ft and makes for some great visual effects. Sunlight was lost totally at about 65 feet. Was a very pleasant dive there. If your looking to work on your skills this is the place to do it. But follow the advise of the shop and don't drop below 20 ft if you don't have 2 working lights, and if you have a canister or HID light, take it, it makes the dive that much more enjoyable.
5/1/2006 Irene Odell 20-30' Water temperature is 78 at surface, 74 at bottom and in the high sixties from 50-80 feet. Though the Grotto is usually a night dive from below 40' due to the tannic water, we could see some ambient light as deep as 65 feet. Saw a few bass, the usual friendly turtles, blue gill and tons of little minnows. Best conditions of the year and its only getting warmer! Many new "objects" have been added to the wall, so there's a lot of new stuff to see.
2/18/2006 Frank Lavallee 25-30' The water temperature is 63 degrees from the surface down to 80 feet. It warms up to 74 degrees as you approach the bottom. Visibility is 25 - 30 feet in the shallower depths, but is 10 feet or less on the bottom.
12/23/2005 Walter Pickel 20' Above Halocline Nice and tannic...Viz above the layer was about 20'. Viz under the layer was about 5'.
Click here if you would like to contribute any information or resources for this system.
Description Type Date Author Remarks
 Home Page Web Site
 System Map Map
 System Map #2 Map
Sslect Search Radius:
System Depth Cave Cavern OW Last Report Distance (mi)
 Overview Information Available for Wards Sink  Ward's Sink 198 True True True 9/30/2022 9.1
   Arch Sink 197 True True False 7/18/2021 9.3
   Palm Sink 197 True True True 10/15/2019 0.7
   Rock Sink False False True 3/24/2019 5.1
 Overview Information Available for Salt Spring  Salt Spring 330 True False False 12/13/2014 3.8
 Overview Information Available for Waynes World  Wayne's World 280 True False False 8/16/2013 1.6
   Isabella Spring 110 True False False 5/22/2013 4
   Free Ride Cave 120 True False False 10/10/2009 4.2
 Overview Information Available for Cedar Island Springs  Cedar Island Springs False False False 9/19/2009 2.4
   Double Keyhole 230 True False False 1/11/2009 5.1
 Overview Information Available for Horseshoe Spring  Horseshoe Spring True True False 1/10/2009 3.6
   Heart Spring 270 True True False 8/3/2008 1.8
 Overview Information Available for Bobhill Springs  Bobhill Springs False False False 12/29/2007 7.2
 Overview Information Available for Jewfish Sink  Jewfish Sink 200 True False False 9/2/2007 5.8
   The Jewel 315 True True False 6/2/2006 4.7
 Overview Information Available for Beacon Woods - Round Sink  Beacon Woods - Round Sink 150 True True False 9/25/2005 1.6
 Overview Information Available for Beacon Woods - Nexxus  Beacon Woods - Nexxus 150 True False False 1.2
   Nemesis Sink 250 True True True 7.6
 Overview Information Available for Beacon Woods - Smokehouse Pond  Beacon Woods - Smokehouse Pond 150 True False False 0.8
 Overview Information Available for Beacon Woods - Golfball  Beacon Woods - Golfball 150 True False False 0.7
   Willow Sink True False False 13.5
 Overview Information Available for Beacon Woods - Briar Sink  Beacon Woods - Briar Sink 150 True False False 0.8
   Garden World Sink 250 True False False 5.2
   Brett's Toilet Bowl 40 True False False 4.1
   Cauldron Spring 85 True False False 4.1
   Gar Spring True False False 3.4
   Whiskey Spring True False False 3.6
   Coffee Sink False False False 8.2
   Snook Spring 120 True False False 4.1
   Star Sun Spring 120 True False False 4.1
 Overview Information Available for Beacon Woods - Stratamax  Beacon Woods - Stratamax 150 True False False 0.8