Our Family

Come meet the family!

John Sims ~ Instructor #CD11274

Owner & Course Director

Contact:  john@scubastuff.com

Our Director of Training and Education, John was first certified to dive in the late 1970’s. He started teaching diving in the late 80’s. As he starts his 35th year of teaching scuba diving, John is proud to say this is all he does. It isn’t a “part-time” gig, but a full-time love affair with teaching Scuba Diving. As one of the very few certified active Course Directors in Southern California, he is able to teach divers to become both scuba instructors and instructor of instructors (Instructor Trainer). He is the “old guy” with a youthful spirit and a love of teaching diving that is both calming and exciting at the same time. A little different, but very cool.



Debbie Sims ~ Instructor #15994

Owner & Equipment Guru

Contact: debbie@scubastuff.com

While most everyone that visits knows that Debbie is married to Big John, what they are often surprised to learn, is that she has been in the industry longer than he. Debbie has been rebuilding regulators and working on dive equipment since 1982. You know you have somebody special on your team when the manufacturers call you to help diagnose a problem. That actually happens. Debbie is a little old school. She usually doesn’t tell you your equipment is too old and you need a new one, unless that is the ONLY option. Debbie still cleans and polishes all the regulators. The BCD’s are meticulously cleaned. Even the Velcro is brought back to as good a condition as possible. Every piece of equipment sold or serviced comes with Debbie’s thoughts on how to keep it functioning for years to come. Debbie doesn’t “make due”. Debbie makes it right. In the nearly 30 years at the shop Debbie has had 3 complaints. All exactly the same. She restored a product to “factory new” and the customer complained because it breathed too easy. Sometimes you forget how well this equipment is supposed to operate. 

Debbie is also the mom of the group. When we travel, she takes care of all the land-based planning. If there is a group doing something, Debbie makes sure everyone is well taken care of. If something isn’t right, let her know. She will go to battle for you to make sure it is. It’s a family operation and she is the Mama Bear.


John R Sims ~ Instructor #51924

Instructor & Assistant Store Manager

Contact:  johnsimsjr@scubastuff.com

Little John is the baby of the family. Quite nearly born in the dive shop, he has well over 20 years experience in the store, including 11 years of teaching. At 6’3″ he isn’t so little, but he is the virtual personality of the store. Bringing both the talents of his Mom and Dad to bear, when you work with Little John, you get the whole package.  If your nervous, he will calm you. If you need a little motivation he will cause you to reach for the stars, all the while making sure you are safe and comfortable in our ocean environment. He is also our “go to guy” for underwater hunting. You can’t help but smile when you’re spending time with Little John. As the president of our Dive Club, he helps provide you with all the activities you could possibly want to try in diving. He is a great mentor, teacher and all-around Big Brother (did we mention 6’3″).

Rachel Cushman

Staff Instructor & Assistant Dive Safety Officer: Aquarium of the Pacific 


Rachel has an an undeniable, unforgettable, irreplaceable, burning desire to show the next generation the beauty and necessity of underwater life. This pulsing feeling triumphs all persuasive thoughts and pushes for the pursuit of creating a better tomorrow.

More than a passion, her purpose is to help audiences everywhere cultivate an understanding of the ocean and develop a relationship with the life that lives there.

Matt Muldorf

Staff Instructor, Father of 3 small children &  Bon Vivant

Matt came to us several years ago as he relocated from the Bay area into the Huntington Beach area.  He has been an instructor for a number of years, knows the industry well and is without a doubt one of the funniest people we have ever worked with.  His children keep him on his toes and that makes him all the more fun to dive with and learn from.

He does a lot of our beach dives, so if you hang out with us long enough, you will enjoy the experience that is “Matt”.  

Mike Sieverman

Instructor & Public Safety Diving Expert

Contact:  mikes@scubastuff.com

Update:  2021 – Mike has semi-retired from staff teaching for Ocean Gear; however, he still remains active with diving and will always be a member of the family.  He continues to be our Public Safety Course Director.

A retired Police Officer and U.S. Army Veteran, Mike brings an Esprit d’ Corps to the Ocean Gear family. While not blood related, Mike typifies family in the shop. He will joke with anyone, help everyone who walks through the door and be the first person to stick up for you if you stumble. He is family.

Mike is also one of the creators of the NAUI Public Safety Diver course and has his own comprehensive training program for Public Safety Diving. His is the only program in Southern California that is POST approved and recognized by Police, Fire and Sheriff Departments for proper dive training.

Mike is a true team player. He is willing to try almost anything if it means the diver will benefit in the end. He has willingly been both the innovator and the guinea pig for several of our slightly crazy ideas. He is always ready with a good laugh and brings just the right amount of sarcasm to the project to keep you motivated. He is detailed and meticulous as his military background demands, but is flexible and reasonable to figure out the perfect solution to some unique circumstances. You will really enjoy learning and diving with Mike.

Masa Komura

Staff Instructor, Equipment Technician and, quite simply, the nicest guy on the planet!

Masa has been with our program forever.  While he is retired from regular staff duties, he pops into the shop a few times a year.  When not teaching scuba, he is a Golf Pro that works with some professionals on both the PGA and WPGA tours.  When he is in town, he will stop in, rebuild a few regulators, watch the shop, entertain our clients and ALWAYS make you feel better having spent some time with him.  Hard to say it any better than before – The nicest guy on the planet!