5mm or 3mm + vest for tropical liveaboards / dive-intensive trips?

[_scuba_steve]

Looking for advice on purchasing a wetsuit - my diving will be exclusively tropical diving on liveaboards or dive centric trips (Bonaire, CocoView) where I'll be doing 3-5 dives/day for a week.

My previous dives have been one or two dives here or there - not dive after dive day after day. I tend to run cold in general, I'm 5'9" 140lb athletic build and am quite sensitive to the cold - and I am looking at either a full 5mm or a full 3mm + vest. Either option I'll be packing a 3mm hood and wearing a skin suit underneath (partially to make getting in/out of the suit repeatedly easier).

I like the idea of the 3mm + vest due to the (perceived at least) versatility - but:

1 - Is a 3mm + vest going to be comparable in warmth to a 5mm?
2 - Would a 3mm + vest be more comfortable than a 5mm? Or less so since 2 separate pieces? Would the 3mm + vest be even more a pain in the butt to take on and off repeatedly than just a 5mm between dives?

I'm using "vest" rather than a specific thickness vest since I'm not sure how thick I should go if I go that route - so any guidance if you think that is preferable would be appreciated.

I've seen DM's/instructors do suit + vest on prior trips and is why I bring that combo up - never bothered to ask why they did that over a thicker suit, however.

The LDS recommended a 5mm - have a Waterproof W2 5mm on order to check sizing - going off the sizing chart at least, my measurements are dead on for a size small regular.

 

[Doubler]

Steve,
I am also from the GPNW. I dive exclusively liveaboards in tropical places. I only take my 3 mil and do just fine. I will admit I begin to chill on dive 3 or 4 of the day and that a hooded vest is probably a real good investment.

 

[Bubbletrubble]

The thickness of the wetsuit really depends on the temperature of the water and your personal tolerance to cold.

I run a little colder than most people. I tend to hover for 90% of a dive and take photos of stuff. I used a 3mm + hood in Bonaire and Cozumel in December (avg. water temps 78°F-80°F), and I felt warm enough.
If I did a Galapagos liveaboard from June to December (avg. water temps 70°F-74°F), I would probably have to move up to a 5mm, 7mm, or perhaps bring along my drysuit.

The nice thing about using a layering system (3mm + vest) is that you have the flexibility to not wear the vest if you're too warm. That being said, I can't ever remember a time when I've ever been too warm during a dive. Perhaps this is because I'm reasonably good at guessing the right amount of exposure protection for me for given water temps.

If you know you run a little colder than others and you seem to be caught in-between two thicknesses of wetsuits, I'd recommend going with the warmer suit/layering configuration.

In terms of sizing, there's no substitute for actually trying on a wetsuit. Different manufacturers incorporate different "cuts" into their suit. I've tried on some wetsuits that I swear were trying to choke me to death.

 

[_scuba_steve]

Steve,
I am also from the GPNW. I dive exclusively liveaboards in tropical places. I only take my 3 mil and do just fine. I will admit I begin to chill on dive 3 or 4 of the day and that a hooded vest is probably a real good investment.

Whoops - misread nvm

 

[SubMariner]

Steve,
I am also from the GPNW. I dive exclusively liveaboards in tropical places. I only take my 3 mil and do just fine. I will admit I begin to chill on dive 3 or 4 of the day and that a hooded vest is probably a real good investment.

In a similar vein, I wear a vest with a "Snoopie Beanie" + my 3mm if I am doing liveaboards in warm water. However, if the water is 78F or below, I take my trilam drysuit. (If you look at my profile picture I'm wearing the "beanie" & my drysuit in the Red Sea one March.)

Enjoy your trip,

 

[Bratface]

Just like you said, take the 3mm and hooded vest. And have fun, Roatan is amazing.

 

[Divedoggie]

Generally, a 3mm will dry faster than a 5mm. So if you will be hanging the suit up between dives, chances are it will dry off. IMO that makes it much more comfortable to put back on!
Many vests are 3mm to 5mm which when combined with the 3mm suit, puts a nice amount of insulation around your core.
Wearing a hooded vest, bibbed hood or a beanie really helps with keeping you warm.
Some vests are designed to go against your skin, under the suit. Others, usually with a zipper, go over the suit. I have found the former to be warmer.
Some 3mm suits are warmer than others! Waterproof, Camaro Seamless or Stingray, and Pinnacle Elastaprene Merino are all warmer than average.
The suit, whether its a 3mm or a 5mm needs to fit properly. Vest too.

 

[Divedoggie]

Pinnacle Merino Elastiprene 3mm Mens Wetsuit discounts on sale Pinnacle Wetsuits

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Here is a great value 5mm(Call about the size though. It says men's small, which should be size 48, but the size 36 is women's): Camaro 5mm Seamless Dive Wetsuit - Semi-Dry (For Men) - Save 62%

 

[rongoodman]

I get cold in a Pinnacle 5mm Merino lined suit on liveaboard trips by the end of the week. For my next one I will either add a hooded vest or just take a dry suit.

 

[Hank49]

Looking for advice on purchasing a wetsuit - my diving will be exclusively tropical diving on liveaboards or dive centric trips (Bonaire, CocoView) where I'll be doing 3-5 dives/day for a week.

.

I live and dive Belize. The temps here are pretty similar to Coco View (Roatan?) and we get quite a variation for which I use different combos of wetsuits.
I would go with a 3 or 3.5 mil full and a 3mm hooded vest in the "winter" months when we're at about 77-79 F temps. I would guess a 5mm would work too for me in that season but I don't have one.
For "Spring time" I use a 1.5 mm full with a 2 mm or 3mm hooded vest.
In the "summer" I can use only the 3mm hooded vest, or a full 1.5 mm suit.

These combos are adequate for me to be in the water for 4-5 hours free diving or doing 3-4 scuba dives in a day. I'm as you described yourself, in that I'm not very cold tolerant.