Question Experience with Fleece and Thinsulate drysuit undergarments

[Doctor Rig]

In my research on drysuit undergarment materials, I’d like to briefly summarize my findings on these insulation materials and get real world feedback from experienced divers.

As a general statement, I’ll start saying for a given thickness, Thinsulate is a superior insulating material than “Fleece”. Thinsulate keeps you warmer for a given thickness. As a result of this, a Thinsulate undergarment and drysuit will more likely require less weighting (lead) than a “Fleece” undergarment and drysuit (for a given temperature comfort level).

Thinsulate is a 3M trademarked product, so I’m guessing it’s properties should be pretty consistent. “Fleece“ manufactured with different specs and from different sources has variable insulating and physical properties. So some fleeces can be better than others, but in general Thinsulate should always be the better insulating material by a varying amount.

My take on this is a Thinsulate undergarment is likely to be a superior undergarment material and has the important attribute to allow divers to dive with less weight since it displaces less air for a given temperature comfort level.

As the OP, I attempted to state my research findings in an accurate manner. Just FYI, I have no affiliation with anyone and am nothing more than an mechanical engineer, (trained in heat transfer) trying to share what I‘ve learned in researching and evaluating undergarments for my first dry suit.

After skiing for many years, I’ve got tons of cold weather garments. In evaluating their use, I’ve concluded that some of my Patagonia capalene could be used as a base layer, but none of my fleece would be of any value, as I wanted to keep my weighting to a minimum.

Looking at the market place, some manufacturers appear to offer some higher tech fleeces that closely compete with anything in the market especially for the best mid layer undergarments. For outer layer under garments and colder water Thinsulate is supreme, IMHO.

Thanks for those that have posted and those that will be sharing your real world experiences on this important topic.

 

[rx7diver]

As the OP, I attempted to ...

FWIW, I wore Patagonia Capilene as a base layer (for wicking) beneath my DUI Thinsulate drysuit underwear, beneath my DUI CF200SP (crushed neoprene) drysuit for extended-range Great Lakes wreck diving. This combination worked very well for me for the types of decompression exposures (run times <= 1.5 hours) I was diving.

ETA: Also, the type of Thinsulate used for skiing, snowmobiling, etc., is not the same as the Thinsulate recommended for diving.

rx7diver