Bruce Justinen
Contributor
Hi, I am Bruce Justinen, President of SEASOFT SCUBA in Olympia, WA and we make neoprene drysuits custom and stock. Here is my take.
First of all the suit has to fit, the boots, the seals, all of it, if not, no suit is worth diving. But given a great fitting suit...
"There are a lot of "experts" out there telling people which drysuit they should buy. The problem is they are telling people based on their "experience". Usually that "experience" is predicated on the one or two drysuits they have owned.
It reminds me of the "pickup wars". Traditionally people are very loyal to a brand of pickup, Ford, Chevy, Dodge (now Ram), etc. Rarely, if ever, had they ever actually driven the "other guys" pickup but they would be sure to tell you that they would NEVER own one.
That's often how it is with drysuits. But for the person wanting to buy a drysuit there are a lot of mixed messages, a lot of advice from divers, instructors etc. who have only used one drysuit or type of drysuit.
I have over 5,000 drysuit dives over the last 34 years. I have experience with virtually every type of suit, vulcanized rubber, compressed neoprene, crushed neoprene, traditional neoprene, trilaminate shell, thin shell, heavy duty shell, stretched fabric over shell and hybrid neoprene suits and here is my experience with the two most widely used type of drysuits.
Here are the main differences between shell suits and neoprene suits.
SHELL SUIT: In a shell suit the diver basically dives some type of a squeeze in order to have a useable suit (remember, the fabric doesn't stretch). Because the suit has to be cut large enough to accomodate for their movements in a non-stretchable fabric, there is space for air to move in a large mass. This big "bubble" in the suit would create potential mayhem for their buoyancy and control. So in order to eliminate this chaos, they dive with some type of squeeze (they do NOT add air or they add very little, as they descend).
Since, the diver is diving with a squeeze and since air is what gives them warmth and since the suit itself has NO thermal protection they are forced to wear big thick undergarments. They have NO choice.
For buoyancy control, they would use their BC underwater, if they used their drysuit, instability ensues for most divers.
NEOPRENE SUIT: In a neoprene suit the diver uses air to keep warm. Since the suit fits like a loose wetsuit and because it stretches the air does not form a large bubble. The air is dispersed all around the suit as a layer of air. As the diver descends he/she adds air to this layer. They will get a minor movement of air but it does not move as a "body" of air. The diver does not need thick undergarments because the suit itself is providing a layer of insulation but so is the layer of air. During the dive they can add additional air that can continue to provide additional insulation.
In the winter, many divers will actually add a couple of pounds of weight so that they can add a small amount of additional air to their drysuit for additional warmth. In a neoprene drysuit: Air = Warmth.
They will not use their BC for buoyancy during the dive. They will typically ONLY use their BC on the surface.
SHELL SUIT: Once again, because shell suits do not stretch, it must be made larger, creating a large amount of excess material. This excess material creates hydro-drag. The more surface area (lose fabric, wrinkles, etc.) that water has to flow over, the more drag it produces. This uses up air, slows the diver down, tires them out prematurely and quite frankly nothing good comes from hydro-drag.
From Wikipedia: "the larger the surface area presented to the water, the more hydro-drag produced."
NEOPRENE SUIT: Since neoprene stretches, it makes for a closer fitting drysuit and presents far less surface area to the water, typically 20-30% less fabric. Thus, there is less hydro-drag in a neoprene drysuit and it is not uncommon for divers to have longer bottom times with part of that reason being that they are also warmer.
SHELL SUITS: So often, even with the thicker undergarment, many divers are cold when they dive their shell drysuits. Of course, part of the reason is because they are diving in a squeeze (no air in the suit). This causes the suit to collapse in on the undergarment and forces it against the body. This can potentially eliminate a portion of its thermal protection. Also, the suit itself has NO thermal protection and with no layer of air, the only thermal protection is the undergarment.
NEOPRENE SUITS: The neoprene suit delivers the first layer of thermal protection, the dispersed air around the diver delivers the second, and the undergarment is the third layer of thermal protection. Three will always beat one.
The argument made by some is that you need more weight for a neoprene drysuit. The answer is that you do! If you were diving a shell suit with a squeeze then yes, diving warm in a neoprene drysuit will require more weight but that is like saying that steel tanks costs more than aluminum. Well, yes, they do, but the advantages are worth it.
In the case of neoprene vs shell, as amazing as it is, the neoprene is usually the less expensive of the two.
First of all the suit has to fit, the boots, the seals, all of it, if not, no suit is worth diving. But given a great fitting suit...
"There are a lot of "experts" out there telling people which drysuit they should buy. The problem is they are telling people based on their "experience". Usually that "experience" is predicated on the one or two drysuits they have owned.
It reminds me of the "pickup wars". Traditionally people are very loyal to a brand of pickup, Ford, Chevy, Dodge (now Ram), etc. Rarely, if ever, had they ever actually driven the "other guys" pickup but they would be sure to tell you that they would NEVER own one.
That's often how it is with drysuits. But for the person wanting to buy a drysuit there are a lot of mixed messages, a lot of advice from divers, instructors etc. who have only used one drysuit or type of drysuit.
I have over 5,000 drysuit dives over the last 34 years. I have experience with virtually every type of suit, vulcanized rubber, compressed neoprene, crushed neoprene, traditional neoprene, trilaminate shell, thin shell, heavy duty shell, stretched fabric over shell and hybrid neoprene suits and here is my experience with the two most widely used type of drysuits.
Here are the main differences between shell suits and neoprene suits.
SHELL SUIT: In a shell suit the diver basically dives some type of a squeeze in order to have a useable suit (remember, the fabric doesn't stretch). Because the suit has to be cut large enough to accomodate for their movements in a non-stretchable fabric, there is space for air to move in a large mass. This big "bubble" in the suit would create potential mayhem for their buoyancy and control. So in order to eliminate this chaos, they dive with some type of squeeze (they do NOT add air or they add very little, as they descend).
Since, the diver is diving with a squeeze and since air is what gives them warmth and since the suit itself has NO thermal protection they are forced to wear big thick undergarments. They have NO choice.
For buoyancy control, they would use their BC underwater, if they used their drysuit, instability ensues for most divers.
NEOPRENE SUIT: In a neoprene suit the diver uses air to keep warm. Since the suit fits like a loose wetsuit and because it stretches the air does not form a large bubble. The air is dispersed all around the suit as a layer of air. As the diver descends he/she adds air to this layer. They will get a minor movement of air but it does not move as a "body" of air. The diver does not need thick undergarments because the suit itself is providing a layer of insulation but so is the layer of air. During the dive they can add additional air that can continue to provide additional insulation.
In the winter, many divers will actually add a couple of pounds of weight so that they can add a small amount of additional air to their drysuit for additional warmth. In a neoprene drysuit: Air = Warmth.
They will not use their BC for buoyancy during the dive. They will typically ONLY use their BC on the surface.
SHELL SUIT: Once again, because shell suits do not stretch, it must be made larger, creating a large amount of excess material. This excess material creates hydro-drag. The more surface area (lose fabric, wrinkles, etc.) that water has to flow over, the more drag it produces. This uses up air, slows the diver down, tires them out prematurely and quite frankly nothing good comes from hydro-drag.
NEOPRENE SUIT: Since neoprene stretches, it makes for a closer fitting drysuit and presents far less surface area to the water, typically 20-30% less fabric. Thus, there is less hydro-drag in a neoprene drysuit and it is not uncommon for divers to have longer bottom times with part of that reason being that they are also warmer.
SHELL SUITS: So often, even with the thicker undergarment, many divers are cold when they dive their shell drysuits. Of course, part of the reason is because they are diving in a squeeze (no air in the suit). This causes the suit to collapse in on the undergarment and forces it against the body. This can potentially eliminate a portion of its thermal protection. Also, the suit itself has NO thermal protection and with no layer of air, the only thermal protection is the undergarment.
NEOPRENE SUITS: The neoprene suit delivers the first layer of thermal protection, the dispersed air around the diver delivers the second, and the undergarment is the third layer of thermal protection. Three will always beat one.
The argument made by some is that you need more weight for a neoprene drysuit. The answer is that you do! If you were diving a shell suit with a squeeze then yes, diving warm in a neoprene drysuit will require more weight but that is like saying that steel tanks costs more than aluminum. Well, yes, they do, but the advantages are worth it.
In the case of neoprene vs shell, as amazing as it is, the neoprene is usually the less expensive of the two.
