Where once DUI was the only real option for a drysuit, now many manufacturers have entered the market with equally good products, often at much more reasonable prices. Otherwise, rubber suits are still rubber suits.
Almost all diving activities, whether in the tropics or in colder waters, will require some sort of exposure suit. For local conditions, this means either a full heavy wetsuit or a drysuit. For the tropics, there are thinner wetsuits and fabric skins, but these are never warm enough for use around here. Water temperatures in the north Atlantic vary from just above freezing at depth during the coldest part of the year to mid-seventies at the surface during the warmest. Typically, you can expect high-fifties to low-sixties at depth even over the summer.
Apart from protection from the cold, there is also a need for mechanical protection. Wherever you are diving, there are probably lots of sharp rusty edges, barnacle-covered rocks, old lost fishing lures and line, and miscellaneous junk, and that's not to mention critters that bite. Skin gets very soft in the water, and you can cut yourself badly just by grabbing something or bumping your head. In the tropics, sun protection in shallow water and on the surface is also a consideration.
Beginners generally start out with a wetsuit for several reasons. Foremost is cost. You can get into a good wetsuit for a fraction of what even a cheap drysuit costs. Familiarity is also a factor, since you probably got certified in a wetsuit, and by now you feel comfortable in one. Finally, wetsuits are perceived to be easier to use than drysuits. This is only partially true, and if this is your only reason for selecting a wetsuit over a drysuit, you are making a big mistake, and there is no reason not to start out with a drysuit instead.
With a wetsuit you can expect to be diving in relative comfort around here from late June to October. Below 50 ft or so, I always feel cold in a wetsuit, no matter what time of year it is. With a drysuit, you can dive year-round in relative comfort. If you plan to dive a lot, the extra investment could be well worth it. You may never notice the difference between two different masks or two different regulators in the water, but you will always be acutely aware of the chilly discomfort if you make a bad selection in your exposure suit.
Monthly surface water temperature data from the Long Island weather buoy (44025). Bottom temperatures are considerably lower in the summer months. Draw your own conclusions.
The minimum exposure protection you should plan on for New Jersey diving is a full 6 or 7 mm neoprene wetsuit, with equivalent hood, gloves, and boots. A common misconception about wetsuits is that the water inside keeps you warm. This is absolutely false - the less cold water that gets in, the warmer you will be. ( Some folks actually bring jugs of hot water and pour it into their wetsuits just before the dive. ) Once the suit floods and the water inside warms up, you do feel better, but that water got warmer because you got colder. The trick is to keep as much as possible of this warmed water inside the suit, but almost every motion you make will pump out some warm water, and bring in more cold.
Two things will reduce this pumping tendency. The first thing is a properly sized and fitted suit. A wetsuit should be snug, without crushing you, and there should be no large empty spaces inside when you put it on. Many people have a hard time finding a wetsuit that fits just right. The second thing is a well made suit. Features of a superior wetsuit include:
gusseted main zippers with interior flaps to reduce leakage
ankle and wrist zippers for ease of donning and good fit
skin-in seals at the wrists, ankles, and possibly the neck to reduce leakage
tightly assembled seams that will not open up and leak over time
durable kneepads to avoid cuts and abrasions in this high-wear area
Lately, a number of manufacturers have come out with wetsuits that are almost entirely "skin-in" material inside, something which is supposed to radically reduce water flushing. I can't say if it works or not, but it makes sense. Unfortunately, at the same time the two-piece farmer john style wetsuit seems to have gone out of fashion in favor of one-piece designs that are inherently thinner.
Expect to pay around $300 for a good cold-water wetsuit. Also, be aware that neoprene wetsuits wear out in as little as 3-5 years depending on use, and an old wetsuit is not as warm or watertight as a new one. Therefore, a used wetsuit is probably not a good deal at any price, especially if it has been heavily used in chlorinated pool water like most rentals. Wetsuits also shrink. As the air leaks out of the tiny bubbles in the material, it contracts, and after a couple of years it probably won't fit any more, even if you didn't get fatter !
A neoprene wetsuit insulates you by virtue of those tiny air bubbles in the rubber, which are what give the neoprene its insulating value. A problem with all wetsuits is that the deeper you go, the more these tiny bubbles compress, and the less insulating value the suit will have. This is especially unfortunate since the deeper you go, the colder it gets, and the suit basically fails you when you need it most. Another problem with thick neoprene wetsuits is their buoyancy varies from almost 20 pounds at the surface to near nil at depth. In order to compensate for this, you need a lot of lead weight at the surface to get down, and then a Buoyancy Compensating Device ( a "BC" or "BCD" ) to support all that lead at depth.
A lot of manufacturers nowadays are making a lot of hype over the advanced materials they use in their wetsuits. They often charge considerable premiums for features that are of little or no value, such as the inclusion of titanium in the neoprene. ( In theory, flecks of titanium would reduce radiative heat loss. Trouble is, with a temperature difference of perhaps 40°F between the inside and outside of the suit, radiative heat loss is practically nil anyway. ) A good wetsuit as described above will keep you as warm as a wetsuit is going to keep you, without costing a fortune. To get warmer than that, you will need a drysuit. See Beginner's Recommendations.
There are also more and more semi-dry suits coming on the market nowadays. These are basically wetsuits with enhanced seals that limit flooding and water exchange during a dive. This is probably a great idea for the tropics, but I don't think much of it for local use - for the extra cost, get a real drysuit instead.
Rinse your wetsuit well inside and out after every day of diving, unless you want it to really stink. Henderson, in right here in Millville NJ, makes excellent wetsuits that are widely available at good prices.
Serious New Jersey divers wear drysuits. A drysuit is a waterproof suit with built-in feet that seals around your neck and wrists ( some have built in water-tight gloves and/or hoods as well, ) and a waterproof zipper to close it up. The idea is that although you are underwater, you don't get wet, but this is not entirely true. No seal is perfect, and certain actions will let small amounts of water leak in past the seals. However, most of the moisture that accumulates in a drysuit comes from its occupant, in the form of perspiration. If water can't get in, then it can't get out either. Perhaps these should be called dampsuits instead of drysuits.
Still, in cold water a drysuit is much warmer than a wetsuit. This is because you maintain a constant layer of air between you and the cold, and air is an excellent insulator. While air is also the insulating factor in wetsuits, there is a difference. With either suit, the volume of air, and therefore the amount of insulation, compresses as you go deeper. With a wetsuit, there is nothing you can do about this, but with a drysuit, simply tap the inlet valve, and compressed air will flow from your tank into the suit, and puff it up again, keeping you warm. An added benefit is that by keeping the suit inflated to a constant volume, you maintain constant buoyancy, from the surface to the bottom, which can actually reduce the amount of lead you need to carry. Some divers even dispense with the BCD, considering that a drysuit can be thought of as a full-body BCD, but this is not recommended, and it is convenient to use the BCD as a quick trimming device and for surface flotation.
Learning to use a drysuit is less difficult than you might think. You must hook up an extra hose from your regulator to the drysuit inflator. This hose should be routed around your right side, the same as your regulators. As you descend, you will need to add air to the suit. The suit will "squeeze" you uncomfortably if you fail to do this. You will have to relearn buoyancy skills in the water with the extra air volume of the suit, but this is not difficult. Finally, you must vent off the excess air from the suit as you ascend. I will not go into any of the potentially disastrous but easily avoided mishaps that can occur while using a drysuit. Taking an inexpensive drysuit specialty course or at least practicing with an experienced friend is strongly recommended.
A drysuit should fit well, but need not fit as precisely as a wetsuit. This can be a real boon to those who do not fit the 'average' body mold. Neck and wrist seals are made of either thin latex or thicker neoprene. After using all types, my preferences are for a fold-under neoprene neck seal, and heavy-duty latex wrist seals. A neoprene neck seal will likely leak a few drops on every dive, but no more, and is quick and easy to put on. Latex neck seals require much fussing with to get them to lie right, and then they leak anyway. The neoprene neck seal is also warmer and lasts longer. Heavyweight latex wrist seals are far better than the standard fragile thin ones: longer-lasting and easier to get on and off.
Drysuits come in several different designs, with varying features. The least expensive drysuits are made of the same thick neoprene material as wetsuits. All of the problems of variable buoyancy, loss of insulating value, and limited life that I described above with wetsuits carry over to these drysuits. Their big advantage is cost; some of these can be had on sale for nearly the same price as an top-end wetsuit. Another advantage is that these suits are pretty tough, owing to the thickness of the material, and easy to repair. Some people prefer the built-in insulation that these suits provide, which can be augmented optionally with undergarments.
A lot of the old-timers and commercial divers that I know use these suits and swear by them. An instance when this type of suit may be preferable is if you do long shallow decompression hangs. At shallow stop depths, the neoprene in the suit will puff up again, giving you some added insulation when you need it during long periods of inactivity. An old neoprene drysuit will eventually begin to leak as the gas bubbles in the material rupture into each other and eventually create passages for water to penetrate the suit. There is no good way to repair this, so a used neoprene drysuit is probably not a good buy.
Next up the ladder in drysuit technology is thin fabric drysuits. The best of these are made of three-layered sandwich material, called trilaminate, while cheaper ones are made of less durable two-layer material, and some industrial suits are made of a single layer of slick rubber, mainly so that they can be easily cleaned after use in toxic environments. All of these suits have several things in common. None has any insulating value of its own; for warmth you must wear undergarments. None is particularly abrasion resistant, although trilaminate suits are not exactly delicate either, and some of the newest ones look very tough indeed, with ballistic nylon outers. Finally, none has any appreciable stretch to the material, which means the suit must be cut rather baggy to allow for movement. Fabric suits are very light and pack up very small, making them good for traveling. They are also more expensive than neoprene suits, and to this you must add the cost of any undergarments.
The best drysuits are made of materials such as crushed or high-density neoprene. This material is extremely long-lived, tough and abrasion resistant, and also stretchy, allowing the suit to be cut much finer than a "bag-suit". Although the material is thin ( about 3mm, ) it is also very dense, and these suits are nearly as heavy and bulky as ordinary neoprene suits, especially when wet, so they are not really suited to traveling. They also have practically no insulating value of their own, and must be used with undergarments. These drysuits are also shockingly expensive, to which you must add the cost of any undergarments. Since the gas in crushed neoprene has already been squeezed from the material, such suits are not prone to inevitable leakage like ordinary neoprene suits. I own two old crushed neoprene suits, but given the tremendous improvements in trilaminate materials, I don't think crushed neoprene is worth the extra cost any more.
Different drysuit manufacturers place the zipper in different locations. The most common and lowest-cost ( shortest ) zipper location is across the back of the shoulders. This obviously requires some assistance from a buddy to get in and out of the suit. Some suits use a variation where the zipper runs around the back of the neck and down the front. Others use a zipper across the front of the shoulders or around the waist, and you may still see an old suit now and then with a crotch zipper ( Try to figure out how that is supposed to work. ) the most expensive ( longest ) but best zipper placement is diagonally across the front, from the right hip up to the back of the left shoulder, making the suit "self-donning" if you are limber enough. While zipper placement is really a matter of choice, valve placement is not. The inflator valve should be in the center of the chest, and the exhaust valve should be high on the left arm. Avoid other valve placements and gimmicks such as mini-exhaust valves at the ankles and wrists - there is definitely only one right way about this.
Drysuit undergarments can be anything you want, from sweats and long johns to expensive purpose-made jumpsuits. The best material is water-shedding polyester fleece, the worst is highly absorbent cotton. A layering approach is usually best, depending on how cold the water is. Jumpsuit-style undergarments ( as shown ) with knit cuffs and a nylon outer shell are both windproof and waterproof, which will keep the inevitable small leaks and condensation off you, and also keep you warmer on cold days when you are out of your suit. Add extra layers underneath as necessary. Polyester or wool socks complete the outfit.
Of the high-tech insulating materials available today, Polartec fleece ( polyester micro-fiber ) is much better for diving than Thinsulate. Polartec material retains more of its insulating value when wet, and is also longer-lasting and easier to launder than Thinsulate, which quickly pills-up and becomes worthless. Highly suitable and reasonably priced Polartec undergarments can often be found in the skiing section of your local sporting goods store over the winter. Just remember, with any of these high-tech plastic materials - one trip through the clothes dryer and you can throw it away.
I'm trying to keep this all objective, but I have observed that there seem to be two kinds of drysuit divers: those that have DUI's, and those that wish they did. DUI
is arguably the Cadillac of drysuits, and certainly the most expensive. A crushed neoprene DUI drysuit can be expected to last a lifetime, with necessary maintenance. For those on a tighter budget, a good quality trilaminate suit and some long underwear from K-Mart will keep you pretty warm for a lot less money, and if you can afford this level of investment, then I think you should skip the wetsuit and go straight to dry. I wouldn't recommend heavy neoprene drysuits for beginners, even though they are the most affordable. And no RockBoots.
A final accessory for drysuit diving is ankle weights - small lead anklets that help you maintain your equilibrium with the drysuit on. I would also recommend some sort of weight-integrated BC system for use with a drysuit, although I see a lot of folks do fine with just a plain old weight belt.
In a typical drysuit course, you will learn how to do emergency air dumps by pulling open wrist or neck seals. This "skill" works fine in a warm pool with bare head and hands, but how are you supposed to do it in the real world with long gloves and hood on? Much scuba training is not as well thought-out as it seems.
Drysuits are much longer-lasting than wetsuits, but they also have higher maintenance costs, as seals and zippers wear out over time. Some ballpark drysuit maintenance figures:
item - local rates, rush job
( when is it not ? )
replace neck seal
1-3 years (100 dives)
replace wrist seals
1-2 years (100 dives)
2-3 years (150 dives)
replace inlet valve
replace exhaust valve
service inlet & exhaust valves
repair minor leaks & test
Small leaks and tears are easily repaired at home using AquaSeal. Rips and tears in foam neoprene are easily repaired with neoprene cement, and then waterproofed with AquaSeal. Valves and other hardware may be affixed to flexible suit material with RTV silicone. Repairs should be made to the inside of the suit, where they will not show. To mark the location of a small leak, push a pin through it ( no harm - it leaks already! ) then apply sealant to the inside, and pull the pin out.
Old leaky AquaSeal is easily removed using a Dremel tool with a sanding barrel. Keep the tool moving to avoid overheating the material, and be careful not to cut into the soft suit material underneath. AquaSeal works much better with Cotol thinner and accelerant. "Cotol" is nothing more than toluene ( right, aka methylbenzene ) - a common paint stripper and thinner, that is also used as an octane-increasing fuel additive. Toluene is available by the gallon ( about $7 ) at any better hardware or paint store, or by the half-ounce ( also about $7 ) at the dive shop. AquaSeal is generally available in the fishing/boating section of Sports Authority for $4.99 / ounce. Toluene is an excellent thinner for all sorts of other adhesives as well.
As you can see, the averaged cost of maintaining a drysuit is roughly equal to buying a new wetsuit every year ! The real difference is in the quality of cold water exposure protection - there is no comparison. If you plan to dive a lot in cold water, the extra expense of a drysuit is well worth it.
in many ways sets the standard for drysuit design, they are not perfect. One of their latest innovations is the "RockBoot" - a sneaker-like nylon shoe that fits over the foot of the suit, which is reduced to a sole-less waterproof sock.
RockBoots are one more thing to pack, one more thing to put on, one more thing to take off, and one more thing to wear-out or lose or forget.
They are left and right. Left and right fins were banished from diving long ago. Why be bothered ?
They are bulky and stiff, requiring oversized fins which are often simply not available. Your existing fins will almost certainly not fit and will have to be replaced.
Yet they are also close-fitting, and limit your options for insulation in cold water.
Yet they are not particularly comfortable.
They don't even close up with Velcro like a decent pair of sneakers, but have bothersome laces. Try that with cold-numbed fingers.
"RockBoots" are totally unnecessary for boat dives, where you merely have to stagger a few feet to the side of the boat and fall overboard, then climb back up the ladder in your fins. "RockBoots" are actually bad for beach diving, where the sand will inevitably work its way inside the boot and abrade away the foot of the drysuit until it leaks. I don't go hiking in a drysuit, and I will not wear hiking boots while I am diving !
Maybe in some parts of California, where the shoreline really is rocky, these things are somewhat useful. In the rest of the world, "RockBoots" make absolutely no sense, and nobody I have ever spoken to about the "RockBoots" on their DUI suit has ever had anything good to say about them. Luckily, you can still get the old-style Vibram-sole drysuit boots as a special-order item, although ironically DUI now charges extra for them.
If you are unfortunate enough to already have a suit with "Rock Boots", one thing you can do is get an inexpensive set of wetsuit booties and use them instead !
Rant Against DUI
In my opinion, DUI perfected the drysuit around 1990, and has been screwing it up ever since. They seem determined to glue everything but the kitchen sink onto their suits - huge kangaroo pockets, useless (dangerous) knife-holders, "warm-neck" collars that just don't work, colored overlays that add nothing but weight and bulk, with unnecessary zippers that trap sand and grit, complicated failure-prone seals and dry-gloves, and finally, the afore-mentioned hated Rock Boots.
Of course, these are all things they can charge extra for, and this seems to have been used as justification to raise their prices into the stratosphere - pushing $3000. Even so, some of the components are just plain cheap, like the narrow black suspenders that are so prone to end up in your crotch instead of over your shoulders. How much would it cost to make them right - wide and yellow, with quick releases so you can untangle them without taking the suit off. Also, the fit of even their "custom" suits is questionable, and I detest the ridiculously narrow ankles that make getting the suit on and off unnecessarily difficult, especially with several pairs of socks in the wintertime. DUI seems to design their suits for San Diego, as if no other place existed on earth.
You can now get two good suits from other manufacturers for the price of a single "loaded" DUI. My old DUI finally wore out, and I now use a Bare. In particular, take a look at new products fromAbyss and Diving Concepts. The compressed neoprene suits look especially nice.
Hood, Gloves & Boots
A hood is critical for maintaining warmth in the water. A good hood will be as close fitting as possible, and have a generous collar for tucking into your wetsuit, thin skin-in seal around the face, and baffled vents in the top to release bubbles. A neck skirt is much less necessary with a drysuit, but it is a simple matter to cut one off if you don't like it. A neoprene cold-water hood should be at least 5-6mm thick.
The face-hole of a hood should be as small as possible - there is no reason to expose any skin here. The face seal of the hood should overlap your mask skirt, with just barely enough room below for your regulator. You can always trim out a too-small face-hole, but a too-big one pretty much negates any other good qualities a hood may have. Ideally, with mask and hood on, you should expose a small patch on each cheek, and no more.
An alternative for drysuit divers is the attached dry hood. This is usually made of thin latex, and depends on a dry insulating cap underneath for warmth. When it's really cold, go ahead and wear two hoods.
Diving gloves should be close-fitting, with long, gusseted, zippered or Velcro gauntlets that overlap your suit sleeves. This is especially important with a drysuit, since the glove will protect the delicate wrist seal on the suit. Thin tropical gloves are of very limited use in the north - your gloves should be at least 5mm thick. Three-fingered mitts are much warmer than five-fingered gloves, and are really not much clumsier. They are also much easier to get on and off, which makes me wonder why so few people use them. A little spray soap will make any glove easier to get on.
Whatever glove design you use, make sure it has a tough, abrasion-resistant material on the palms and high-wear areas. The best I have seen is Kevlar, but most have some kind of pattern of little plastic dots, like gardening gloves. These quickly wear off, leading to the premature demise of the glove. To extend their life, get an inexpensive can of neoprene cement from your local dive shop, and paint the palms of your gloves with a layer of it ( not Kevlar ones, though. ) Do this when the gloves are new, and repeat as necessary. You can also cement to repair the inevitable nicks and cuts that will occur.
Drysuit divers also have the option of using dry gloves. Similar to a dry hood, the dry glove extends your drysuit seal around your hands. These gloves are usually a thin rubber material, and if you tear it you can flood your whole suit, which is why I would not recommend them.
Wetsuit divers will require boots to go along with their suits. Again, a minimum of 5mm thick, with long fully gusseted zippers. If you plan to do a lot of shore diving, a heavy shoe-like sole may be useful, otherwise there is no need to spend a great deal of money on boots. A common newbie mistake is to wear your boots outside your suit. This way, they balloon as you swim, and are worse than worthless. Always tuck your boots inside your wetsuit legs for best effect. Of course, drysuit divers don't need boots - they're built-in. But you may still want a pair to make your fins fit in the tropics.
Some people claim that wearing socks inside your boots keeps you warmer. I don't see how. Add a short piece of shoelace or reel line to all your zipper pulls, and it will be much easier to work them. Just knot it at both ends, don't make a snag-prone loop.
The heavyweight cold-water wetsuit is probably responsible for the premature demise of more nascent diving careers than any other factor. These awful things are simply uncomfortable and ineffective. For all the stiffness, squeezing, bulk, and extra weight of 5-7mm wetsuit, in the end it really doesn't keep you warm, and most cold-water wetsuit divers are pretty miserable creatures. I have seen the constriction and topside overheating of one of these things make its poor wearer sick on dry land, never mind on a boat out at sea.
The argument that heavy cold-water wetsuits are easier to use is patently false. A wetsuit has a mind of its own, and will make wide depth-dependant swings in buoyancy over which the wearer has no control. How is that better than a drysuit, which the user can consciously trim for constant buoyancy during the descent, and which semi-automatically trims itself during ascent ?
My recommendation for someone just getting started is to get a good comfortable 3mm wetsuit or Polartec skin for the tropics, and initially restrict your diving to that. You will enjoy yourself, and become a better diver. When you are ready for local diving, don't buy a heavy wetsuit. Rent or borrow one for a few exploratory dives, to see if you really want to do this sort of thing. If you do, then save your money and get a drysuit. If not, then you will still have a good rig for the tropics, and you won't have lightened your wallet by $300 or more for a rubber straightjacket that you will soon not want.
My own cold-water kit consists of:
2 DUI front-entry crushed neoprene drysuits ( I long ago gave away my 7mm wetsuit ) with the old-style CF-200 boots, not RockBoots. One suit has a latex neck seal, the other has a neoprene; I have no real preference between the two. Both suits have long, heavyweight "industrial" latex wrist seals. Both suits have already seen a lot of heavy use ( one is a 1998, with over 300 dives on it, the other would have to be carbon-dated to know for sure ) and are holding up well in my opinion, with no more than expected maintenance ( seals, valves, zippers, small leaks, etc. )
In drysuit underwear, I started out with a nylon-shelled DUI Thinsulate jumpsuit, which wore out sooner than I would have hoped. I replaced it with a medium-weight nylon-shelled Polartec Andy's jumpsuit, which I have been much happier with. This is just about perfect by itself for most of the season. I also have a medium-weight DUI Polartec wooly-bear ( fuzzy green ) which I seldom wear because it is too warm. Colorful Polartec socks are thin and warm, and can be layered-up as needed. Lightweight Polartec skiing underwear ( tops & bottoms ) from Sports Authority provides extra under-layers in cold water.
Although it is rather expensive ( $60 vs. $40 ) I use a DUI warm-neck neoprene hood. My five-year-old one is still warmer than anything else I have ever used. In gloves, I use 6.5mm Kevlar-palmed Deep-See three fingered mitts, all year, regardless of the temperature. ( Divers2 in Avon has them. ) With maintenance, I can make a pair of these last two or three years.
In the tropics:
I use a generic Polartec jumpsuit, mainly for protection from the sun. It is not as warm as a 3mm wetsuit, but more comfortable. I also use a thin pair of gloves for the same reason ( if they tell you can't wear gloves, tell them to go to hell. ) 6mm neoprene booties ( leftover from my wetsuit ) fill in the foot pockets of my fins, so I can use the same pair here or there. A Polartec suit like this can also be used as a drysuit underwear layer in a pinch.
Finally, whether you are in the tropics or off the coast here, the sun on the water will cook you fast. A broad-brimmed hat is essential to protect your face, ears, and neck. A baseball cap is not enough. Don't be afraid to wear long sleeves and sweat pants, and shoes, not sandals. Use lots of sun block ( although I personally don't trust the stuff ) or better yet, keep to the shady side of the boat, or even inside.
The only acceptable DIR exposure suit seems to be a non-buoyant thin-shell drysuit. Buoyant wet and dry suits are discouraged because of the extra air and weight they require. If this is taken to mean only trilaminate suits, many of these are too fragile for wreck diving, although that situation has been improving. DIR discourages the use of ankle weights; I see no reason for that. I'm not sure how lace-up Rock Boots have escaped criticism from the DIR community, since they sure look like entanglement hazards to me.
Drysuits: Zippers, Seals, Valves & Maintenance
There's no doubt about it, drysuits require a great deal more maintenance than wetsuits. However, much of it is well within the capabilities of a home handyman with readily-available materials and tools. The following guide should give some idea of what is involved in owning a drysuit, although there is no need for you to do these things yourself if you don't want to !
The waterproof zipper of a drysuit is a really neat device. It is quite different from a normal clothing zipper, and exactly how it works is not obvious. Here are some close-ups of an old zipper that I cut up:
This is the view you see most of the time - the zipper pull from the outside. Note how the rubberized material is folded inside the teeth of the zipper.
Also note the stray fibers peeling off this worn-out zipper.
This is the same part viewed from the inside. The zipped-up section shows how the inner teeth on each side interlock, pressing the material tightly together to form a waterproof seal.
On this cut section of zipper you can see that there is actually a double seal - both inside and outside the teeth. As near as I can tell, the teeth do not actually pierce the material anywhere - it is clamped around them. The inner part of the teeth interlock, drawing the surrounding rubberized fabric closely together.
Finally, the brass zipper teeth themselves, at right. The outer part of each zipper tooth is merely a clamp to hold the inner part in place and guide the pull. It is the small inner part of the tooth that actually does all the work, holding the zipper shut, while the surrounding material forms the seal. Therefore, when waxing your zipper, be sure to do the inside as well as the outside. Not shown are the molded rubber stops at each end of the zipper which assure that the ends are watertight.
This type of pressure-sealing zipper was originally developed for the space program, where it was used in high-altitude pilot's flight suits and early astronaut suits ( although current Space Shuttle suits do not use zippers for seals. ) At right is a 1950s-era Mercury pressure suit. The zipper, plainly evident diagonally across the front of the suit, would be familiar to any drysuit diver. On a space suit, the purpose of the zipper is to hold a higher pressure inside the suit, while on a diving suit, there is normally very little pressure differential, and the zipper is merely required to keep the water out.
Drysuits existed long before the invention of the waterproof zipper. These suits generally sealed up using flaps of rubber around an entrance slit. The two flaps were brought together and rolled up to form a seal. This type of diving suit actually predates the wetsuit, which could not have come into existence before the invention of foam rubber after World War Two.
Repairs & Replacement
Drysuit zippers eventually begin to leak, as the material unravels along the outside edge from repeated use. Zippers can also fail outright if a tooth pulls out. Zipper life can be extended by regular waxing, both inside and out. Sometimes, an apparent zipper leak may actually be a seam leak. This is easily fixed with AquaSeal. Zipper replacement does not look all that difficult, but given the price of a good zipper - $200-$300 - and the possibility of ruining it if you screw up the installation, I would leave this job to a shop.
Valves & Inflator Hose
Drysuit inflator valves are simple devices that generally do not fail. I had one begin to leak once, and no attempt at servicing it would make it stop, despite the fact that I could see nothing apparently wrong with it. Replacement is simple, however, and parts should be available from your dealer. Valves are sealed onto the suit using RTV silicone, not AquaSeal. The clear stuff from the auto parts store works fine. Likewise, exhaust valves are simple to replace, but difficult to service. In fact, the typical drysuit exhaust valve is a fiendishly clever device ( it is actually an adjustable double one-way valve in a single body ) that is very difficult to properly reassemble, so I don't recommend trying to service one. Don't overlook the possibility that an apparently leaky valve may actually be a suit puncture near the valve!
Ever price a replacement DUI inflator hose? $65 !!! Now I happen to like the big fat knob on the DUI hose - if you ever need to disconnect a runaway suit inflator, that will do the trick much better than a small knurled BC inflator, But I don't like that price. So when your DUI inflator hose wears out, just buy a regular $20 inflator hose, and transplant the DUI knob ( and the beefier DUI spring ) onto it. The parts fit right on, and the job takes about 5 minutes if you are handy.
Wrist & Neck Seals
Latex Cone Type
Regular & Heavy-duty
Latex Long (DUI 'RS') Type
Latex Bottle Type
Regular & Heavy-duty
There are several styles of drysuit wrist seals. The options are material, weight, and shape.
Most drysuits come from the factory with lightweight latex rubber cone-style wrist seals, pictured above at left. These have just a narrow contact area around the wrist to make the waterproof seal. When this narrow band stretches from use, the seal leaks and must be replaced. Some manufacturers offer options in wrist and neck seals.
Long-style seals have a much longer tapered skin-to-seal contact area, for a more leak-proof and longer-lasting seal. These seals are bi-thickness - heavier at the base where the seal attaches to the suit sleeve, and thinner near the end where your hand goes through ( although still much thicker than a regular-weight seal. ) DUI refers to this style of seal as "RS", for "Rubber Suit."
Bottle-type seals have a large untapered contact area. While the lack of taper makes them very easy to get on and off, it also means that the seal must be sized precisely to your wrist, and when it stretches from wear it will leak, assuming it did not leak from the beginning.
Neoprene wrist seals ( not shown ) are much longer-lasting than any latex. They are also easier to get on and off, although not as watertight. Sometimes a neoprene seal is used over a latex one, for a double seal. Dry gloves are yet another option.
Heavy-duty latex ( and neoprene ) seals are easier to put on than thin regular-weight latex seals. Unlike thin regular-weight seals, which roll up annoyingly and require much fiddling-with to get them to lie flat, with heavy-duty seals you just shove your hand through and you're done. All styles of heavy duty seals are referred to variously ( and confusingly ) as military and/or commercial.
My own preference is for long, tapered, heavy-duty latex wrist seals.
All latex seals begin to degrade immediately after manufacture, eventually turning gummy, stretching, and finally tearing. My records show that heavy-weight seals are not particularly longer-lasting than normal-weight seals - 12 to 18 months is a typical life expectancy. Neoprene seals last longer - several years may be expected, but repeated stretching will eventually cause a neoprene seal to take a permanent set, at which point it will have to be replaced.
Repairs & Replacement
Replacing latex wrist seals is a fairly straightforward operation that can easily be tackled at home if you are reasonably handy. The DUI Drysuit repair Guide (PDF) gives complete instructions on the matter. Replacing neoprene wrist seals is more difficult, as they properly ought to be stitched on. One option is to simply cut off a worn set of neoprene seals and replace them with latex.
Replacement wrist seals may be ordered from DUI, or Leisure Pro. Leisure Pro generally stocks the fine-looking heavyweight cone-style seals pictured at right, by Bare, part # BRE69397. These cost about $25 / pair, and will usually arrive overnight to NJ by any shipping method. I keep an extra set on hand at all times. All rubber products have a definite shelf life, as deterioration starts immediately after manufacture, whether they are used or not. Shelf life of all rubber products, as well as cements, can be greatly extended by storing in your freezer.
There are some things you can do to extend the life of old seals before they ultimately need to be replaced:
Latex seals deteriorate differently at each end: the base will typically dry-rot and crack where it joins the suit sleeve, while the end will turn gummy and sticky and eventually tear. Cracks at the base can be covered-over with AquaSeal, thinned 50-50 or more with Cotol so that it adheres to the Latex. ( AquaSeal doesn't really like to stick to latex, but if it is thinned enough, it will stay on for a while. ) This is an ugly repair that is really just temporary, so don't get the AquaSeal on the suit itself, just on the seals. Also, sometimes the AquaSeal on the inside of the seal-sleeve joint comes loose and begins to leak. Turn the sleeve inside out, and strip and reseal anything that looks bad. Small punctures in latex seals may be repaired with glueless bicycle patch kits.
At the other end of the seal, stickiness may be smoothed out with any of the available "Seal Saver" products, which are really just silicone lubes. This may also restore some stretch and suppleness. Do not get this stuff anywhere near the base of the seal where it meets the sleeve, just apply it around the ends, inside and out. Oiling-up the end of the drysuit sleeve will make it much more difficult to adhere a new seal when the time comes. This is again just a temporary measure.
Neoprene seals may be serviced as well: when the seal has stretched and started to leak, cut a long narrow V-notch from the end to the base, cutting out the old seam in the process. The notch should be about 1/4 " wide at the outside edge. Then, using as little neoprene cement as possible, butt-join the two edges of the notch, to make a new narrower cone. Back the joint with a small amount of thinned AquaSeal. You probably won't get away with this trick more than once, as eventually the neoprene will lose so much of its stretch that it will have to be replaced outright, but it may add a year or more of life. Punctures in neoprene seals may be repaired the same as suit punctures, and "Seal Saver" may also be applied as described above.
Everything said above concerning wrist seals also applies to neck seals ( right. ) Neck seals have similar life expectancies, and repair and replacement is also generally similar, although replacing a big neck seal is much more difficult than replacing a small wrist seal. Getting one of these on straight takes some dexterity and cleverness, especially since you only have one shot at it! If you'd like to try, replacement neck seals are available from DUI. With roll-under neoprene neck seals, the notching trick works especially well.
Many of the odd-looking hangers you can get at the dive shop are actually very useful. Hanging up foam neoprene items is much better than storing them flat or folded, which can make permanent creases and crush spots. Upright hanging also allows items to dry faster and more thoroughly. Keep rubber items away from fumes and ozone - i.e. a clothes closet is a much better place than a garage.
At right is an accessory hanger on which you can store and dry gloves, boots, and hood. Below are two suit hangers. The hugely flared shoulders on the drysuit hanger allow air to circulate inside, and also spread the weight of the suit across a large area, avoiding pinched corners. The less expensive wetsuit hanger is perfect for drysuit underwear as well. Shell-type underwear should be hung up inside-out.
"Shoulder-saver" Drysuit hanger
Wetsuit / underwear hanger
Suits should be stored with zippers open. If your drysuit has suspenders inside, do not hang them on the hanger. This will only wear them out prematurely; the suit material is plenty strong enough to support itself.
The foot-hanger at right is used to hang a drysuit upside-down from the boots, allowing it to drain through the neck and arms. This is useful when cleaning the suit, both inside and out, although it should not be used for long-term storage. Leisure Pro sells them.
I make no claim as to the accuracy, validity, or appropriateness of any information found in this website. I will not be responsible for the consequences of any action that is based upon information found here. Scuba diving is an adventure sport, and as always, you alone are responsible for your own safety and well being.