Why forearm dumps?

[Spectre]

I've been drysuit shopping lately, and the one I'm looking at I can have the dump valve put where ever I want when it's made. I hear some people recommend fore arm dumps, but I've not found much relating to why the forearm is better...

Can people embellish on what's better with having the dump valve on the forearm vs. the shoulder? Are there any cons people have found with the forearm dump?

 

[Scubaroo]

I was pushed to get one installed by a buddy - he finds it much easier to vent air on ascent with the forearm dump, as you are raising that arm with the BC inflator hose anyway - this automatically puts the forearm dump at the highest point in the suit, and aids in dumping air from the suit. A shoulder dump may still require some shoulder contortions on ascent to make sure air vents.

So I'm told. I have only done a dozen or so drysuit dives, and just got used to raising my shoulder to dump air (although at times I wished I could at least try the forearm dump for comparison). I suspect it would also help getting in and out of your harness (my shoulder dump could hardly be called low-profile, and it's now become a buddy-assisted maneuver to get in and out of my harness because the shoulder strap hooks up on it), and I've had some kelp hook around it as well.

 

[Big-t-2538]

For one individual I know, she got a viking suit last year with a shoulder dump. Since she is fairly skinny, when she raises her arm to dump, the shoulder dump isn't at the highest point, and she experiences bouyancy problems. In her case, a forearm dump would be better b/c she can raise her fore-arm higher than her shoulder......

Just one case

 

[canuckdiver]

I prefer the wrist dump myself, it allows you to put your wrist over head as the highest point, to get more air out of your suit.
The other reason that I have run acroos, is if the valve lets a litte water in, then it's in the wrist, not running dwn my armpit!

 

[MechDiver]

Scubaroo once bubbled...
I was pushed to get one installed by a buddy - he finds it much easier to vent air on ascent with the forearm dump, as you are raising that arm with the BC inflator hose anyway - this automatically puts the forearm dump at the highest point in the suit, and aids in dumping air from the suit. A shoulder dump may still require some shoulder contortions on ascent to make sure air vents.

So I'm told. I have only done a dozen or so drysuit dives, and just got used to raising my shoulder to dump air (although at times I wished I could at least try the forearm dump for comparison). I suspect it would also help getting in and out of your harness (my shoulder dump could hardly be called low-profile, and it's now become a buddy-assisted maneuver to get in and out of my harness because the shoulder strap hooks up on it), and I've had some kelp hook around it as well.

Having the suit and wing/bc vent at the same time is a definite con to me. Seldom would I want to vent both at the same time. I would also think the forearm dump would take needed room on your arm (slate, compass, b/t, whatever), and would make it harder to clear the harness. I have no trouble clearing my drysuit dump valve as I take out my right arm first.

I can't see the need for this at all.

Phil

 

[Bob3]

Most cuff dumps are non-adjustable, not to mention smaller diameter with less volume dumping capacity.
Care must be taken so the undies don't restrict air flow to the exhaust.
They have been known to cause some serious mischief for newer drysuit users when they are the only exhaust valve installed on the suit.

 

[Uncle Pug]

I have both... a forearm (wrist) dump on a trilam. and a shoulder dump on a CF200... both are full sized low height adjustable valves.

I prefer the forearm dump.

The issue of the undergarment plugging the valve would be the same for shoulder mount or forearm mount... but with the right undergarment material and valve design it shouldn't happen with either.

The feature of dumping both suit and wing at the same time is IMO one of the things I like best about the forearm dump and I leave the dump full open for the dive.

 

[MechDiver]

Uncle Pug once bubbled...
The feature of dumping both suit and wing at the same time is IMO one of the things I like best about the forearm dump and I leave the dump full open for the dive.

Don't agree at all with dumping both at the same time, but that aside;

How do you handle valve shutdown on left post without dumping your suit? Would you have to close down the dump valve first? And where is the valve relative to your wrist?

Phil

 

[Uncle Pug]

MechDiver once bubbled...
How do you handle valve shutdown on left post without dumping your suit? Would you have to close down the dump valve first? And where is the valve relative to your wrist?

Phil I keep as much gas out of my suit as will go with the adjustable valve all the way open... (if I wanted to keep some more gas in I would adjust the valve a few clicks closed.)

My valve is midway between elbow and wrist leaving just enough room for my compass between the valve and the drysuit rings.

 

[MechDiver]

Uncle Pug once bubbled...

Phil I keep as much gas out of my suit as will go with the adjustable valve all the way open... (if I wanted to keep some more gas in I would adjust the valve a few clicks closed.)

My valve is midway between elbow and wrist leaving just enough room for my compass between the valve and the drysuit rings.

Okay, sounds logical. Would be interesting to try sometime.

Phil