Trim is a commonly missed or forgotten part of being a good diver. Trim refers to your horizontal position in the water, why is this important?
Being in trim, means you have the smallest profile when moving forward in the water; making finning easier and reducing energy used. Also, it helps to keep your fins away from the sea bottom, so you don’t kick up a sand storm or damage the coral.
Think of yourself like a see-saw, with the pivot point at your waist. Moving weight up towards your head will cause your head to tilt down. The closer to your head the more effect a weight will have; while moving it down below your waist will make your head tilt up.
Knowing your dive gear is important to getting good trim, and again this is an advantage of owning your own equipment. For example, some BCDs have built-in trim weight pockets; to allow you to place weights at alternative locations.
Are your fins positive or negatively buoyant? They can affect your trim, for example, ‘Jet Fins’ are very negatively buoyant and can cause you to be in a head-up trim.
A heavy 1st & 2nd stage can cause you to go into a head-down trim, as well as the weight of the cylinder valve.
You will find good trim is easier to achieve when using Sidemount as the cylinder is lower down your body, so having less effect on your trim.
The locations of your weights are important if you want to achieve good trim, it may not be suitable for them all to be fitted onto a weight belt or in weight pockets of your BCD.
An easy place to fit a weight if needed (to tilt your head down) is the cylinder cam-band. You can also add pouches onto the strap or even make a mini weight belt for the cylinder.
If you find that you are always head down, fitness ankle weights may be an option to ‘balance’ yourself.
Always remember, however you arrange your weights you still need to achieve neutral buoyancy!
It can often be hard to know if you have good trim or not, if you don’t have the ‘feel’ for it simply ask your buddy for assistance on a dive.
They will be able to easily see your trim position, and can even help move/adjust weights if needed. It is always best to discuss this with your buddy prior to the dive, to avoid misunderstandings or unnecessary stress/problems.
Most RAID training centers & instructors will be able to offer a Buoyancy Workshop. This can help you to understand how your own buoyancy and trim, and improve and fine-tune it. If you can’t find a dive center in your area that offers a RAID Buoyancy/Trim Workshop, let us know.