Drysuit vs Wetsuit

 

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Most of you divers out there reading this probably learned how to dive in a wetsuit.  It’s pretty much standard in most places.  You learn about the different types of exposure protections in Open Water: Skin Suit, Wetsuit, and Drysuit.  Yet, you may not have been given the choice between them or even realized you had a choice (yes, you CAN learn Open Water in a drysuit).  You may have seen other long time divers or even your instructor in a drysuit and wondered, why?

I learned how to dive in a wetsuit.  I had about 100 dives before I made the decision to purchase a drysuit in the middle of summer here in beautiful Southern California.  Yes, you heard that right.  The surface temperature on one of my dives in late June was 71F, but the thermocline at 80 feet deep was 48F.  Brrrrrrr!  That’s when I made the switch and it was the best decision I ever made, second only to deciding to learn to dive in the first place.  I’ve been in my drysuit for more than a year now and over 100 dives, so I figure it’s time to talk about the differences for those of you who might be considering making the switch.

 

The Differences

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Warmth

Probably the biggest and most important difference is warmth.  Scuba Diving year round in Southern California can get cold.  Really cold.  During those winter months in a wetsuit, remaining gas and NDLs (No Decompression Limits) are not the limiting factors for dive time.  It’s body warmth.  I went to dive the Yukon wreck off a San Diego boat charter in January in my wetsuit.  By the end of the second dive, I was uncontrollably shivering and had to scrap the third dive-symptoms of hypothermia.

Water steals our body heat 20x faster than air.  20x!  Wetsuits work by trapping water against your body (when they’re fitted properly anyway).  Your body warms that water up and the water mostly stays there.  There’s some exchange with more of the surrounding cold water, but not as much as diving in a swimsuit or skin suit.  That’s still a lot of body heat being lost.  The wetsuits also provide some insulation based on how thick they are (3mm, 5mm, 7mm, etc.).  However, wetsuits compress as you get dive deeper.  The deeper you go, the thinner your insulation gets. Don’t forget that in most dive locations, the water temperature drops as you dive deeper. Thermoclines can be very noticeable visibily or by temperature gradient. With these thermoclines, you end up chilly .  You can also buy a wetsuit with high quality semi-dry seals, like the Fourth Element wetsuits (which are also higher quality neoprene requiring less lead) or a wetsuit lined with insulating material, like the Pinnacle merino wool lined wetsuit.

Drysuits work by keeping you dry.  The suit has seals at the wrists and neck and a zipper in the front or back to don it.  It traps air inside it which you adjust by way of a low pressure inflator connected to your regulator and a vent in the left shoulder.  You also wear wool, fleece, or down undergarments based on how cold the water is expected to be.  Since there’s no water contacting most of your body, you maintain your body temperature significantly better than a wetsuit.  It’s just like having a thick coat on during a colder day.  You stay nice and warm.  I can’t tell you how many times I’ve heard some local wetsuit divers talk about how they don’t need a drysuit cause they can still get 20-30 minute dives before they’re too cold.  I usually hear this after I finish a 90 minute dive AND am still comfortably warm.

Since warmth is mostly decided on what undergarments you wear, a drysuit can be used in any environment that requires anything more than a swim suit, from ice diving to tropical waters.  All you change is hood, gloves, and undergarments.  As an added bonus, in the summer months I don’t need anything besides my thin, fleece pajamas.

 

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Let’s face it, nobody enjoys putting on a wetsuit.  If it fits properly, it’s snug.  If you’re wet or sweaty, it’ll stick to you and make it more difficult.  This can be reduced by investing in a skin suit, wetsuit donning spray, or a wetsuit that comes with easy don lining.

A drysuit is designed to be loose on you (but not too loose or overly large!) so you have room for your base layers and air.  In general, it is much easier to don and doff.  It has seals at the wrist and neck that take a little practice to learn how to put on and take off properly.  If you yank on them too hard, you can tear them.  Then your drysuit won’t be dry until you replace the seal.  All you need to do is work it on by running your finger around inside the seal to work it down your hand to your wrist (hard to explain, easy to show).  This is one of those little things that makes drysuit training valuable.  Once you get the hang of it, a drysuit is very easy to put on and take off.

 

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Buoyancy

As previously discussed, wetsuits insulate by way of tiny air bubbles trapped in neoprene.  The neoprene and those air bubbles are positively buoyant.  It’s the main reason we need to add lead to our scuba kits to dive.  Since the wetsuit doesn’t move around on you, the positive buoyancy doesn’t change based on body position.  It’s fairly uniform and consistent if you stay at the same depth.

The drawback of wetsuit is it changes buoyancy as you change depth.  Those tiny air bubbles compress with the added pressures at depth.  That means your wetsuit will be less positively buoyant the deeper you go.  Your lead doesn’t change though.  That means the deeper you go, you will need a greater volume of air in your BCD to compensate.

Drysuits buoyancy doesn’t change based on depth.  It doesn’t compress.  The air inside it does, however.  This is why a drysuithas a low pressure inflator hose connected to it.  As you descend and the air inside the suit compresses, you can add air until you are back at a comfortable volume.  Since you can always adjust to the same volume of air regardless of depth, your buoyancy characteristics will be the same – regardless of depth.

One key difference worth noting with drysuits is the positive buoyancy does change based on body positioning.  The air inside the drysuit will always go to the part of your body that is closest to the surface.  Maintaining proper diver trim is much more important in a drysuit.  That means if you go head downvertical, your feet will turn into big balloons and hold you in that position (or start pulling you to the surface.  Another important thing to learn in training).  If you go head up vertical, air will bulge at your neck seal and probably start escaping.  When in proper diver trim, it distributes fairly evenly and is very comfortable.

You might notice having air in your boots makes your feet more positively buoyant than wetsuit boots.  Many drysuit divers use fins that are negatively buoyant or very small ankle weights (1 pound or less) to compensate.

 

Redundancy

This one is pretty straightforward but not something divers really think about.  What do you do if your BCD fails?  If it rips or gets punctured during a dive and you can’t inflate it.  If it happens at 90 ft, your wetsuit is so compressed that you’re probably about 10 pounds negative.  How will you safely get back to the surface?  Since a drysuit inflates with air just like a BCD, it’s a redundant system that improves safety.  You have 2 ways to control your buoyancy.  If your dysuit fails, you can use your BCD and vice versa.

 

 

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This is usually the number 1 factor that divers consider when deciding whether to purchase a drysuit or wetsuit.  If you have read the entire article up to this point, you can probably tell that I have a high opinion of drysuits and consider them well worth the investment.  With that said, let’s break down how much they really cost.

Wetsuits will generally cost somewhere between $300-600 new depending on quality.  Depending on quality, they are expected to last approximately 100 dives before they really start to break down.  By break down, I mean tearing at the seams and compression.  Every time a wetsuit gets used, it gets compressed a little more.  After about 100 dives, your 7mm wetsuit is probably closer to a 6mm or 5mm.  Depending on how gentle you are, zippers are only expected to last that long.

 

You can try to extend the life of your wetsuit by being careful with the zipper every dive or replacing it for about $100.  You can purchase a hooded vest for about $50-150 or an insulating skin suit for about $125-200 to compensate for the compression.  You can buy some water resistant sealant for about $10-15 to patch up the seals or holes.  These are all just band-aid short term solutions.  You’re going to have to get a new wetsuit to replace your old one.

Drysuits very widely based on what material they’re made out of (which will be discussed further in a future post), quality, brand, seals, and extras (pee zipper, pee valve, etc).  They can run anywhere between $1,500 and $3,500.  Although, with some basic upkeep, they are going to last well beyond 100 dives.

If you wax the zippers regularly ($8 for a tube that’ll last a good long while), they will perform for many dives.  I have 3 drysuitswith about 200 dives each.  I have had to replace the zipper on one of them, but I bought it used with an unknown number of dives before me.  The other two are still performing perfectly.  A zipper replacement will run about $150.

With those same drysuits, I have only had 1 seal tear.  The cost and difficulty of replacing will depend on what kind of seals you have.  If you have glued in latex, you’ll have to send it in for replacement.  You’re looking at about $150 for both wrists and about $100 for the neck.  If you have self replacing seals, you can keep those in your save a dive kit and swap them out on site.  For silicone, that’ll run about $60 for a neck seal and $45 for a wrist seal. Some drysuits have seals more unique to their brand, like the DUI latex zipper seals.  Those are a little more expensive, but still less than sending it in.

Depending on what kind of material your drysuit is made of will decide how durable it is.  For example, Cordura will be more resistant to punctures than Bi-lam.  Our Cordura drysuit has about 200 dives and has shown no signs of developing any leaks from wear and tear.  Another drysuit I have with soft socks instead of built in boots has rubbed a little too much from sand getting in the rock boot.  My socks started getting a little wet after about 100 dives.  This was more manufacturer poor design than anything else, which plays an important role when you’re looking to purchase a drysuit.  Regardless of what it’s made of, you should be able to locate and patch minor leaks with some very affordable water resistant sealant, like Aquaseal (about $10-15).  If you cause something more major, you can send it in for repairs.  Depending on how bad it is, you’ll probably spend a few hundred dollars.

These repairs are few and far between if you take care of your drysuit.  With simple upkeep and infrequent repairs, a drysuitcan last your entire diving career.  If you dive regularly, it pays for itself fairly quick when compared to the cost of regularly replacing a wetsuit.  As you’ve probably gathered though, it’s much more than that.  It’s an investment into your own comfort and safety while diving.

-Article written by Jake Fitzgerald of Jade Scuba Adventures.

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