Semi-Dry or Semi-Wetsuit? The Mares 6.5mm Isotherm

Semi-Dry or Semi-WetsuitI am originally from the Pacific Northwest where the dry suit reigns supreme with Puget Sound scuba divers. Where I live now along Maryland’s Chesapeake Bay, I cannot say that a dry suit is a requirement. Nice to have, but not required. I do not know of many divers who use one locally.

In the back of my head, I need a dry suit. I often find myself checking them out online or at the local dive shop when they have one in. A good dry suit is expensive and a good pre-owned one is not easy to come by.

This is where a Mares Isotherm, 6.5mm “semi-dry” comes in. Last fall I came across one and was intrigued by the concept. Reviews were favorable and for a bit over $240, the cost seemed more than reasonable. Had I found the middle ground, the best qualities of a dry-suit at a fraction of the cost?

Yes and no. First off, there is no such thing as a “semi-dry” suit. You are going to get wet. There is no way around it. It’s also a good point to note that wIMG_20140710_182005351hile a dry suit will keep you dry, it will not keep you warm. An insulating layer is still required for that. You can be warm and wet. You should be both warm and wet in a semi-dry suit. I am not a marketer, but it may make more sense to classify these suits as “cold water” wetsuits…

I now have six dives in this suit and feel that I can comment on it with authority. The suit is the typical Mares quality. The seams are all flat stitched and sealed. Zippers are on all cuffs with an additional neoprene cuff-liner to make for a better seal. The primary entry, “TIZIP” zipper requires the assistance of a dive buddy to open and close. It runs across the back of the shoulders and “locks” in place. It is impossible to work by yourself. The chest and back panels are insulatIMG_20140710_182049019ing which is a nice feature.   


What sets this suit apart is that very little water “passes through” the suit. It does a good job of trapping water in it. The water your body heats stays in. I wore the suit during a November oyster dive with water temps as low as 38 degrees. The suit worked well when paired with it’s Mares hood, 7mm gloves and 6mm boots with booties. Temps that low are never pleasant, but this suit made them tolerable.

TIP: Some divers will pour a thermos of warm water into their suits on cold water dives. Less of your bodies energy will then be required to heat the water  already trapped in the suit.  

Flotation with a 6.5mm suit is significant. I have added 4 additional pounds for freshwater and 6 pounds for salt to my BCDs internal weight system. These suits do run small so if you order one, go two sizes larger. I normally wear a large to XL. This suit is a 2XL and fits great.Banner>FREE Henderson Dry Backpack With Purchase Of Select Henderson Jumpsuits! while supplies lasts

What I like most about this Mares, is that you get wet much more slowly than in a typical wetsuit. As a result, there is less shock when getting into cold water. Your body has time to adjust. I have found that if I look down, water will quickly enter through an opening at the back of the neck and straight down my spine. Not fun. A good extended hood would stop this. The hood that comes with the suit is OK and serves its purpose. A hood would with a bib would work better.  I consider this one as bonus.

I am still on the lookout for a dry suit. Eventually I will commit to it and get one (especially if I return to the North West). For the time being, the Mares semi-dry fits the bill nicely.

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