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In Memoriam: Cave Diver Bill Rennaker



Stories and tributes compiled by Rosemary E Lunn
Header image courtesy of Duion Furgason taken at Bill Rennaker’s retirement party.

Read William “Bill” Rennaker’s obituary

News broke at the end of August, 2021 via the National Speleological Society-Cave Diving Section (NSS-CDS), that the respected cave diving educator, Bill Rennaker had died. He passed away at his home on August 25, 2021. The NSS CDS—the largest cave diving community in the United States—paid tribute stating, “The cave diving community has lost a true pioneer, a great mentor, and most of all a friend.”

 “Cave Excursions in Northern Florida (Luraville) is my recommendation! Honest, direct, and won’t sell you useless equipment!” Forum

 “Wow we just lost a giant.” Matt Turner

William D. Rennaker was born in Indiana on January 9, 1944. Bill originally trained and worked as a Master Mason. When he retired in 1992 after 30 years of service as a Supervisor for AC Delco Electronics, he moved to “cave country” in northern Florida because he had fallen in love with cave diving. In 1993, he founded Cave Excursions  with his late wife Pat, and was later helped by his daughter, Linda. He ran the dive center for 25 years.

Bill Rennaker in his shop. Courtesy of

In addition to providing cave diving instruction, outfitting, training, equipment sales, servicing, and gas fills, Roy Reynaud remarked “He [Bill] always kept the shop loaded with unique little pieces of equipment, that when I went inside I just had to have, even though some of them are sitting in my save-a-dive kit to this day, with the price still on them.”  

“The first cave dive shop I visited.” Matthew Jones

“Friendly and great service.” ScubaBoard post

Cave Excursions also offered economical accommodation. Divers from across the globe that were attracted to the flooded Floridan turquoise springs and caves would fly into the Sunshine State and rent one of Rennaker’s mobile homes/trailers for a couple of weeks, and dive the local caves. 

Some, like Canadian explorer, instructor, cinematographer, and Woman Divers Hall of Fame Fellow Nathalie “Nath” Lasselin would drive there. “I’d load up my van with all the equipment I needed. It’s 23 hours straight, door to door, from my home in Quebec to Live Oak, Florida. I would use Cave Excursions when I was diving or teaching cave diving, and always rented accommodations from Bill. He was so welcoming the first time I visited him, it made me want to keep on using Cave Excursions. Prior to his closing, I would dive cave country at least annually, and when possible twice a year. Visiting Cave Excursions and talking to Bill was like going back to family.”

In 2005 Eduardo Sosa wrote for Brasil Mergulho that Floridan cave diving was not only captivating, it was also affordable, because the visitors were able to live with the local diving community. He noted that “…it is possible to have access to divers who made history in this modality.” The team rented cylinders from Larry Green, and got gas fills from Bill at Cave Excursions. “Contact with both of them was something interesting, given the humility and attention with which everyone was receivedtwo of the greatest cave explorers there at our disposal. The important thing to record was that both of them were professional and actively diving.” 

Gas Filling at Cave Excursions  

Live Oak is an excellent hub. Divers are able to access thousands of meters of flooded honeycombed passageways in less than a 10-minute drive. Cave Excursions’ close proximity to Cow Springs, Orange Grove, the perennially popular Peacock Springs, and Telford Spring meant divers had the support they needed on their doorstep. No wonder divers naturally gravitated toward Cave Excursions and spent many a surface interval there. 

“The best part of diving Peacock for me was always the stories I’d get to hear from Bill while getting fills…and that says a lot, since I LOVE diving Peacock.” Cave Diving Forum post 

 “Bill always had a good story to tell when we stopped by for air fills.” Eileen Kennedy

Numerous divers have observed on social media that getting a gas fill at Cave Excursions was entertaining, and that there would be plenty of exploration, equipment, and filling station anecdotes from Bill “if you took the time to listen.” 

“When Bill told a story, he brought me into it with him, and enabled me to virtually be there. This was a real gift and will among other things be really missed.”

“Bill was a very funny guy too. He had a joke on every occasion, and they were damn good jokes.” 

 “I used to love to hang out and listen to his stories of a bygone era.” Cave Diving Forum posts

Bill Rennaker was terrific company, and divers enjoyed just sitting and listening to him. They found his chats not only fun, but helpful too, because he would share insights about the local systems. Celia Evesque stated, “I learned a lot about compressors, about caves and the local systems such as Telford (one of my long time favourites!). Mr. Bill was full of institutional knowledge that he was willing to share for the asking.” 

When someone asked on a cave diving forum for advice about diving “Woody’s Room,” they were advised to “talk to Bill Rennaker. He did the survey there and has the best info and stories.” 

“I’m incredibly grateful for the time I got to spend visiting with Bill as I got fills or just stopped in. He was a really great guy and I loved his stories and learning about his experiences as cave diving evolved. I’ll really miss him.” Jeff Frank

“Bill has always been willing to sit down and shoot the breeze with us about cave diving. He has a treasure trove of information that he willingly shares.” post

“I spent many a surface interval waiting for fills cutting up with Bill telling jokes and stories.” Alan Owens

A visit to Cave Excursions also meant that divers could pick up on important news. Bill Rennaker was a portal to get important information out to the community. 

“Bill Rennaker just called me to say the Suwannee County Sheriff dropped by his shop to tell him that Telford was closed, and anyone found on the property would be arrested. He wanted Bill to ‘pass the word’…” post

In 2018, Kristi Draper posted on social media “My memory drawer is full of many happy moments at Cave Excursions: visiting with Linda and Bill while my tanks are filling, sitting in the plastic lawn chairs sharing my lunch with that crazy chihuahua, studying the maps trying to figure out exactly where we turned that last dive, buying that one piece of gear to replace what broke on the last dive and for some baffling reason not having a replacement in my save-a-dive kit. And the happiest of all…when I needed a special gift to present to my dive buddy underwater at the end of her 100th cave dive. Linda offered up to me a cave arrow necklace she’d had lying around. It made my buddy’s special dive absolutely perfect.” 

Bill Rennaker with Lamar Hires. Photo courtesy of Lamar Hires

Lamar Hires of Dive Rite: “Bill moved to Florida because of cave diving. After he settled in Luraville, he could cave dive every day and got the bug to explore and support his habit by teaching. If he hadn’t dived it, he wanted to. That led him down the path to sidemount, so he could get into the caves less travelled or not travelled at all. I introduced him to sidemount and trained him soon after he moved to Luraville. He later helped in the development of our current sidemount rig.” 

“I remember our boat trip to Rock Bluff; it is a tight high flow entrance and Bill struggled with it. After a few attempts, he gave up and said he would be back. It didn’t take long for him to go back to Rock Bluff with a shovel to make it big enough to get in. He was so happy to get in and make the dive. After that Bill didn’t hesitate to check out any cave and see if he could get into it. He had some close calls but learned and shared what he knew. He made friends with divers who looked for fossils and artifacts in the local rivers.” They talked often about the river caves they found when hunting. Bill made a deal with them, I believe it was: Show me a hole and get a free air fill; if it goes, 10 free air fills. He became the river cave king.” 

Bill’s role in premixed EANx  

Bill Rennaker didn’t just pump air. For several years he was the only go-to place in cave country for technical fills. Accurately partial pressure blending gas is an art, and brewing it in vast quantities takes time and patience. 

“I got my cavern, intro to cave, and advanced nitrox from you. I am one of those people that gets that good feeling when I pull in for a Trimix fill, as I know it will be done right.” Cave Diving Forum post

Both Dive Rite and Submerge Scooters acknowledged that Bill Rennaker banked and pumped an exceptional amount of Nitrox 32 or Enriched Air Nitrox (EANx). 

Cave Excursions Advert. Courtesy of Advanced Diver Magazine Issue 11, 2002.

“One of Bill’s innovations was having the first shop to pre-mix nitrox and sell it by the cubic foot, making it affordable for divers.” Lamar Hires, Dive Rite

Hires told me, “Bill opened Cave Excursions so he could supply nitrox to the community. He knew it was the better option for most of the local caves, and wanted to make it affordable by selling it by the cubic foot. He had many sleepless nights doing partial-pressure blending. When the nitrox stick hit the market, he was one of the early adopters, so he didn’t have to stay up all night to mix.”

“What a visionary he was. Air and nitrox on tap. Drive-up fill out of your truck service. If he saw a better way of doing something, he made it happen. In addition, he was one of the nicest people I  ever knew.” Cave Diving Forum post

“Bill Rennaker is a cave diving instructor in central Florida who also owns Cave Excursions, which must pump more nitrox than anywhere else on earth!” Submerge Scooters

Cave Excursions: The Social Spot

“If you want to hit the springs, come visit Cave Excursions. Great bunch of people and they’ll introduce you to the dive community.” ScubaBoard post

Many divers loved to hang out at Cave Excursions. Bill Rennaker understood the value of face-to-face interaction, and he facilitated this important social aspect of our sport. Roy Reynaud wrote, “I’ll miss the large barbecue shindig he put on every fall where we could all enjoy the company of cave divers from all over, even if we never got to dive with them.”

“The customer appreciation cookouts were all out of this world and full of camaraderie and most excellent food (and of course, awesome prizes) but best of all, there was Mr. Bill and his ever-present smile.” Celia Evesque

“The number and variety of people that would gather at his little white table near the fill stations was amazing.” Cave Diving Forum post

“I remember a chat we had about swimming to the Crypt like it was yesterday, even though it was well over a decade ago. We were sitting at the table next to the shop, in no hurry to go anywhere. I was just starting to learn how much I did not know.” Cave Diving Forum post


 “The cave diving community has lost a true patron.” Dalls Edmiston

Bill Rennaker supported and put back into the cave community; be it a door prize for a local event, or something bigger, such as voluntarily building facilities (steps, decking, changing rooms, etc) at cave diving sites. 

In 1993/1994 Bill and Dale Moats installed the steps leading from the deck into the water at Peacock I with the hope they would last a quarter of a century. Bill wasn’t far out on his estimation. In March 2017 the steps were falling apart, and were rebuilt by North Florida Springs Alliance (NFSA) volunteers. Again Bill Rennaker supported this important work. Cave Excursions, along with Dive Outpost, provided pizza, coffee, cookies, and nitrox fills for the volunteers. 

Cave divers descending the steps at Peacock Springs that Rennaker and Dale Moats built. Photo by the Underwater Marketing Company.

One diver spoke enthusiastically about Bill Rennaker enabling him to dive after a piece of kit failed. “Cave shops are the only places I’ve seen that will loan you something you forgot or broke and simply say ‘have fun’. A couple of years before a first-stage blew a seat and [Bill] Rennaker loaned me one, having never seen me before. I took it back after we got through with class and a week later he sent me back my reg repaired at no charge. He would not let me even pay shipping. I make it a point to send people to places like that and spend all the money I can at the cave shops.” post

“Bill is a great guy. He lent me a light head one time. He didn’t really know me either.” post

Ejido Jacinto Pat Project

 “Bill Rennaker’s enthusiasm and detail, methodical skills were unmatched.” 1996 Ejido Jacinto Pat Project report

A classic example of Bill Rennaker’s patronage was the 1996 Ejido Jacinto Pat Project, in Quintana Roo, Mexico. (A number of cave diving personalities and companies, including Bill, contributed funds to this project. Bill donated US $500, which at the time was an average week’s salary). This money helped enable a team of more than 50 divers to add 12 km/40,000 ft to the cave and connect “Maco’s Marvels” to the Dos Ojos System. At the time, Dos Ojos was the longest known underwater cave in the world, with more than 89 km/55 mi mapped. 

Courtesy of Ejido Jacinto Pat Project.

Jill Heinerth (cave explorer, author and WDHOF Fellow) was part of the project team. She recalled the following story about Bill Rennaker’s involvement. 

“Bill expressed interest in working on the Ejido Jacinto Pat project but said that he preferred to work on his own. He wanted to sleep in air conditioning each night rather than camping in the jungle, so we dropped him at Hilario’s Well, not too far from the main road. It was a sidemount cave with lots of potential. His task would be to push the extents of the cave in a seaward direction. Some of the other team members were interested in learning more about sidemount from Bill. They later described him as a shape-shifter. After two weeks on the project, Bill had surveyed roughly 5000 feet of new cave passages. That sure was an awesome project!”

An Educator That Made Divers Think

 “There’s no such thing as a bad dive. There are just some dives you learn more from.” Bill Rennaker

Bill Rennaker was a NSS-CDS instructor (29030). He had a positive effect on many, making an indelible difference in students’ and individuals’ dive practices, and challenged them to think things through.

“Bill was my instructor and cave diving mentor. One of my favorite quotes that got him in trouble with the cave diver elite was ‘only you can swim for you, and only you can breathe for you.’ Most people misunderstood this to mean that you only took care of yourself and ignored your buddy. His meaning behind that quote was that to be the best possible diver to your buddy you had to be the best possible diver yourself. The way you did that was to use proper techniques underwater and to practice your skills so that when the time came to use them you were ready. Those practice sessions many times over averted a potential disaster for me underwater. I will miss his wisdom, his stories, and the effect he had within the cave diving community.” Cave Diving Forum post

“Bill Rennaker never talked down to me about my SeaQuest Vest BC, and he never talked down to me about being a PADI nearly zero to beyond hero. He did challenge me so hard that my buddy whined about being buddied with me, but at the end Bill congratulated me (both of us) and it was a great experience.” ScubaBoard post

“I did Apprentice Cave with Bill Rennaker, and I thought that he did a great job of making me think about ‘what if’ scenarios, and what the possible outcomes / consequences might be.” ScubaBoard post

“I’m honored to be taught by Bill, a great teacher, a great friend! He made you feel as part of the family!” Joe Rojas

“I was fairly new in the cave diving hobby but dove with some truly exceptional people. I learned to cave dive from who I consider the greatest cave instructor: Bill Rennaker.” ScubaBoard post

 “My job is to educate, communicate, and facilitate…What you do with that information is entirely up to you.” Bill Rennaker

Historical Stories 

Several divers acknowledged that they learned a lot about the early days of cave exploration whilst sitting at the plastic table in front of the shop.

“Cave Excursions is like looking back down the timeline of side mount cave diving. Most mornings we had the pleasure of sitting with the original owner Bill Rennaker chatting about the caves in the area, development of cave diving, and his shop.” Team ProTec

“Without the beauty of the newer sidemount rigs, ours back then were all improvised. We used bicycle inner tubes, something I learned from Bill Rennaker, the equivalent of today’s under-the-arm bungees. They worked.” Philippine Technical Divers 

Matthew Lerp and Frank Stopa hung out for an afternoon at the shop with him on a cave diving trip. Matthew Lerp observed that he “listened to stories and got shown some of the old school dive gear that was used. Was a great learning experience.” Frank Stopa wrote, “learning some of the history of cave diving that afternoon was probably a typical day for Bill, but it certainly left a lasting impression on us.”

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My Visit

When the DEMA Show is held in Orlando, it is a great opportunity to escape to Cave Country for a couple of days and enjoy some wet rocks. In November 2015 Lamar Hires kindly took me diving at Cow Spring. We ended up dropping into Cave Excursions for some fills.

I found it fascinating to observe that customers would reverse their trucks up to the front of the dive centre. When their turn came to get gas, long whips would be walked from the gas bar and attached to cylinders. They would then be filled in situ in the back of the vehicle. As I walked through the dive centre it felt as though I had a history lesson in the evolution and development of Dive Rite gear. There was an eclectic collection of kits, new and old for sale. I could have stayed for hours just rummaging and chatting with Bill Rennaker. We had an interesting conversation. Rosemary E Lunn

Earlier Recognition by Peers

The International Underwater Cave Rescue and Recovery (IUCRR) was founded in 1999. It is an international all-volunteer, not-for-profit public service and educational organization registered in the State of Florida. In 2001, the IUCRR recognized the contribution that Bill Rennaker, along with Larry Green and John Orlowski, had made, and they were awarded an Emeritus title. Bill Rennaker’s title was “Recovery Diver Emeritus.” 

“Each of these individuals have not only been volunteers with the IUCRR since its inception, they were also recovery divers with their cave diving organizations before the IUCRR was created.  They have served with distinction, selflessly, and without any compensation of any kind.  Though retiring from their roles with the IUCRR, each has earned the title ’emeritus’ since their input and support will always be welcome.” IUCRR

Bill Rennaker’s sustained contributions to the cave diving community were also recognized in November 2006 at the National Speleological Society annual convention. He received the “Fellow of the Society” award from the NSS Board of Governors for dedicated service in the field of Speleology.

In 2001, when the news broke, divers posted their congratulations on social media: 

“Congratulations Bill, a well-deserved award!” 

“You are one of the good guys.” 

“No award, or collection of words, can tell you how good we feel when we pull into your driveway, knowing that you love cave diving as much as we do, maybe even more.” 

“Thanks for all you have done for the cave diving community.” “Know we all appreciate what you have done over the years, and hope it will continue for years to come.”

More Tributes to the man, the friend

“Bill Rennaker was a great man, not just in the diving world, but in life itself. I always loved talking to him when getting ready for a cave dive, sitting out front of his home or just out for dinner. I will always remember him by having his signature on my cave diving card.” Peter Garcia Jr.

“I have so many great memories of Bill that I will always treasure. He was a true pioneer of the sport, a fantastic instructor, and a friend to all. I first met Bill in the 90s and learned more from his wisdom than anyone else in the cave diving community. You will always hold a special place in my life.” Cave Diving Forum post

“Bill was simply a gentle giant who was loved by most and had no problem sharing his thoughts, opinions, or beliefs and he was one of the most unique, colourful and interesting people I ever met. I have only the best memories, got a few good hugs and a lot of great laughs and stories and some nice dinners and great diving as a result of him…I even learned quickly what double discing a manifold was all about on my first ‘cave fill’ as we went to dive Cow. He always sent me to amazing places when I was starting out, and I’m glad I’ve had the privilege to share this magical place and the magical man with so many people over the last 20 years.” Matt Mandziuk

 “All the Brazilian Cave Diving Community is in pain for this terrible loss.” Marcus Flávio Horta Caldeira

“I am glad I got to visit him a few months ago. He was my cave diving instructor, cave crack dealer, and friend.” Cave Diving Forum post

“Bill, you were a mentor for so many of us. While you may be gone, know you did tremendous things for our sport, our industry, and helped a lot of new (and old) cave divers along the way and in a special way became an important part of our lives. Believe me when I say from many of us, ‘you will truly be missed’.” Roy Reynaud

“Mr Bill Rennaker… A man is not judged by how much he made or the power he gained in his life, but by the love and knowledge he shared and the lives that he touched.” NSS-CDS

 “He was a good man and a mentor to us for more than 20 years.” Dave Grimm

Dive Deeper:

Leave condolences for the family here

The perilous cave exploration of Convict Springs (

Bill Rennaker was interviewed in Natalie Lasselin’s 2006 cave diving documentary: Facing Darkness

Dive industry “Fixer,” Rosemary E Lunn (Roz) is Business Development Director at The Underwater Marketing Company. This British firm specializes in providing marketing, communications, social media, and event management for the tec-reational and technical diving industry. Rosemary is a PADI IDC Staff Instructor, BSAC Advanced Instructor, Trimix and CCR diver. Before moving into the public relations field, she worked as a professional recreational instructor in the United Kingdom and abroad, on History Channel and National Geographic documentaries, and as a safety diver and model underwater.

She established TEKDiveUSA and organised Rebreather Forum 3 on behalf of AAUS, DAN and PADI. In 2008 Rosemary co-founded EUROTEK, the European advanced and technical diving biennial conference. She has organized the last six events: 2008, 2010, 2012, 2014, 2016 and 2018. Roz is a respected and prolific diving author, an Associate Member of the Women Divers Hall of Fame, and an SSI Platinum Diver. She takes an active role in the scuba diving industry and sits on the SITA Board (Scuba Industries Trade Association) and the BDSG (British Diving Safety Group).


Project Divers Are We

Diving projects aka expeditions—think Bill Stone’s Wakulla Springs 1987 project, or the original explorations of the Woodville Karst Plain’s Project (WKPP)—helped give birth to technical diving….




Header image: Divers positioning a decompression habitat during a recent GUE Project Diver core module. Photo by SJ Alice Bennett, courtesy of GUE.

Diving projects, or expeditions—think Bill Stone’s Wakulla Springs 1987 project, or the original explorations of the Woodville Karst Plain’s Project (WKPP)—helped give birth to technical diving, and today continue as an important focal point and organizing principle for communities like Global Underwater Explorers (GUE). The organization this year unveiled a new Project Diver program, intended to elevate “community-led project dives to an entirely new level of sophistication.” Here, authors Guy Shockey and Francesco Cameli discuss the power of projects and take us behind the scenes of the new program.

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