This April I did a sidemount course (you can read about it here, here, and here). While on that course I used the Hollis SMS 50, my instructors, on the other hand, used the Razor.
Hollis SMS 50 £479.99
What I liked about this harness is that it comes pre-built. One could say that it is ready to wear off the rack. All you have to do is adjust the length of the straps and the position of the buckles and then you are good to go. The harness fits well and looks good once it is on, obviously that is one of the most important factors when choosing your harness. The harness has two short bungees you use to help secure the two cylinders to you – this is contrary to how I was taught. I was taught to use one long bungee that goes across my back. There are a a few small integrated weight pockets but they aren’t enough to really give you what you need. We used additional pockets that were attached to the harness to add additional weight.
I like the Hollis SMS 50, however one of the problems I encountered with it is that due to the fact that the aluminium tanks that I used it meant that I had to use a lot of weight. The weight wasn’t to help me sink at the beginning of the dive, but it was to help stop me from being two buoyant at the end of the dive when I would have both cylinders almost empty and trying to lift me up. I needed to use 10kg of weight to keep me down. This was unfortunate and where the main problem lies. The wing on the harness only gives 10kg of lift. This meant that I needed to rely on having empty cylinders to be buoyant at the end of the dive – not the best situation to be in if you don’t have empty cylinders. Another problem that I found was the BCD dump valve cord was too long, it would occasionally get caught between the right-hand-stage and the harness, meaning that it could be difficult to dump air.
Hollis do make cam bands that are fantastic for attaching to the bottom of a cylinder, making it easier to switch cylinders between dives.
Razor Sidemount US$799 (£520 approx)
Both my instructors, Alan and Steve, use the Razor sidemount. This harness has been developed from years of cave diving experience in Mexico by Steve Bogaerts. He is a British diver who has spent his life diving caves. The Razor is more streamlined than the Hollis SMS 50. It is a more customisable, however it is harder to set up. The Razor comes with the one bungee cord for securing the cylinders. The complete system, all these parts can be bought separately, comes with both the cold and warm water d-rings, the t-bar weight system, and the expandable pocket.
The idea behind the different sized d-rings is that in cold water you are more likely to use steel stages and they do not become buoyant when the air in them is used. You have bigger d-rings to allow for bigger p-clips and for the numbness caused by the cold. The t-bar weight system allows the addition of up to 18kg of additional weight. Unlike integrated weights once this weight is on you cannot take it out without removing the harness. There are benefits to this and there are obvious detriments. The expandable pocket attaches to a pair of d-clips above your buttocks. This is a great idea because the harness has no pockets and you don’t want to have your kit dangling about so that it catches on something. The only disadvantage is that it can float up and thus become ensnared as you pass through tight spaces.
So which one did I buy?
I bought the Razor because it is only slightly more expensive and it comes with more features than the Hollis SMS 50. But the main reason that I bought the Razor is because it has more lift than the Hollis SMS 50. I would prefer to have more lift and not need it, than need it and not have it. Also my two instructors couldn’t recommend it highly enough, and as they are both very experienced tec-divers I am inclined to listen to their opinion. I know that there are other sidemount systems out there (such as the Agir-Brokk one) but I haven’t yet had the opportunity to try them.