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Who should take this course?

Using a Delayed Surface Marker Buoy (DSMB) in the tidal waters of the UK is the only safe alternative to using a shot line for an ascent. The DSMB course is perfect for any diver wishing to gain confidence in the use of a marker buoy and reel or someone who wants to purchase a DSMB and reel set up but isn’t sure which of the many different styles is best for them. If you took your Open Water Diver course prior to the latest revision you may not even have been shown how to use this important piece of kit, so this course is ideal for you.


The speciality is open to anyone with an Open Water Diver rating or higher.


“Absolutely chuffed with how this weekend has gone, I’m filled with absolute gratitude towards you and Robin for sharing your knowledge with me and giving me such first-class tuition. Thank you so much!” 


Open Water & Dry Suit Diver Student

What will you learn?

Through a theory presentation, dry land practice and two dives in open water you’re going to learn how to safely deploy a delayed surface marker buoy, and how to ascent efficiently using one. Over the course of the day, you will have a chance to practice with different styles of DSMB including those filled from a low-pressure inflator hose, those with self inflate mechanisms and simple open-bottomed styles too, so you gain an understanding of the pros and cons of each. We will also look at what style of line carrying system you prefer, from a large reel to a simple spool.

What scuba gear will you use?

You will need all your regular scuba kit, and any reels and marker buoys you have. If you have yet to buy a DSMB or line we will provide a variety for you to use for the duration of the course, and give advice for any future purchases.

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DSMB and Hidden Depths Spools

Hidden Depths Scuba School run two weekly pool dives around Bristol, primarily for scuba training, but also open to club members

Want to Join The dive Club?

How to join

Our dive club membership runs annually and is renewed every January.

To sign up for the dive club all you need to do is submit a Club Membership form along with your club membership fee of £45.

Updates are sent out through email, and you will have access to our members-only Facebook group which is ideal for arranging dives with other club members.