DSMB size - is 6’ overkill ?

[billt4sf]

On the SMB question: we have two, one short one which is easier to inflate under the surface, and a long yellow one that we inflate on the surface in case we get separated.

In any case, it's easier to inflate an SMB at like 25' (8m) than at the 15' (5m) safety stop. So if you're still learning, you might try that.

- Bill

 

[MXGratefulDiver]

I don't understand the want of another hose. But..., I don't dive locally. I usually need to fly to where I want to dive. One less hose is just easier for me. I would rather use my spare reg to fill from the bottom of the bag.

I also don't understand how a closed bottom DSMB is easier to dry. Hang an open bottom and prop the bottom. Gravity works.

I kind of get calling it a "semi-open" bottom. But, to me, it's either open bottom, or it's not.

There's a difference. An open bottom bag is open at the bottom. A semi-closed bag has a one-way valve that allows air in, but won't let it come out if the bag's tipped.

... semi-closed ...

... open ...

... Bob (Grateful Diver)

 

[Dan]

Also it dries faster if you blow it up like a balloon in the sun. Same with BCD. The quicker it dries, the less sun exposure it gets, the longer its useful life will be.

 

[Dizzi Lizzi]

Recently I was being trained in deploying SMB at depth. I had a very difficult time disengaging my low pressure hose, worst yet was I was totally unable to reconnect it. I simply did not have the strength with a pressurized system. My buddy had to reattach it for me when they saw I was oral inflating at the surface. It might be a combination of dexterity and strength, seems pretty hard to imagine doing that in 7ml with gloves! I figured I would just continue to use the smb i have (no OPV valve or inflator hose connection) as I have practiced inflating it at depth...well a 6 foot pool , it takes a little coordination but I can do it, and I feel safer with my bc all connected up. I like safe

Now thanks to @RyanT and @Dan_T I have another option...but I don't like that extra hose.

 

[Dogbowl]

Recently I was being trained in deploying SMB at depth. I had a very difficult time disengaging my low pressure hose, worst yet was I was totally unable to reconnect it. I simply did not have the strength with a pressurized system. My buddy had to reattach it for me when they saw I was oral inflating at the surface. It might be a combination of dexterity and strength, seems pretty hard to imagine doing that in 7ml with gloves! I figured I would just continue to use the smb i have (no OPV valve or inflator hose connection) as I have practiced inflating it at depth...well a 6 foot pool , it takes a little coordination but I can do it, and I feel safer with my bc all connected up. I like safe

Now thanks to @RyanT and @Dan_T I have another option...but I don't like that extra hose.

Yeah, that extra hose is yet another item to be added on to gear, but I guess it’s just one of those things that you eventually get used to and will come to appreciate.

I guess you could always just orally inflate. Are there pros and cons to this? I don’t think anyone’s mentioned this aspect.

 

[MXGratefulDiver]

Yeah, that extra hose is yet another item to be added on to gear, but I guess it’s just one of those things that you eventually get used to and will come to appreciate.

I guess you could always just orally inflate. Are there pros and cons to this? I don’t think anyone’s mentioned this aspect.

Orally inflating a small bag is easy ... the air gets transferred from your lungs to the bag in a single breath, so your buoyancy doesn't change at all during the process.

Orally inflating a larger bag takes some practice, since usually more than a single breath is required*, which will increase your buoyancy. But with practice it's not really all that hard.

... Bob (Grateful Diver)

* unless you're shooting it from 100 feet, in which case a single breath is sufficient ...

 

[outofofficebrb]

If you are diving cold water, oral inflation can be challenging when your face and lips are numb. FYI - the Halcyon metal tips where you don't have to press a plastic thing in while blowing in makes a huge difference when your lips are numb. You just put your mouth over and blow. If you have an OPV, the deeper you do this the less air you actually have to put in initially because it will expand as it gets sent up. You won't have to worry about it popping with an OPV either...so you can be a little more generous with the air if you're not sure. If you are orally inflating a 6' at something like a safety stop depth, and there is swell or surge, and you're taking big inhalations, that will really screw up your buoyancy. That is where having that extra hose is handy. The other alternative is having a semi-closed bottom - you can purge your reg or octo in there or use your exhaust bubbles. You can supplement by oral inflation. (There are some with all 3 - OPV, magnetized semi-closed bottom, and oral inflation tube.) But the semi-closed (semi-open? heh) tends to get floppy on the surface if the bottom is not completely under the water. They get flaccid easily - and you have to ensure you put enough air in them before you send it up and maintain a taut line.

Pros and cons. I've used both.

 

[Kevrumbo]

I have a small standard 1m tall closed DSMB that can be deployed from depth with a spool; as well as a large 1.8m/6ft Diver's Life Raft (discontinued by Halcyon) that can be LP hose inflated at the surface.

Only deployed it once for real as a huge orange surface marker buoy, waving it against a setting sun background behind us, signaling a Liveaboard about half a mile away as my group was being carried away by current in the Sulu Sea/Tubbataha Reefs Philippines -it worked and they saw us. (For a brief moment I thought I was going to sit in it and finally activate a PLB as the last resort).

 

[Trailboss123]

Yeah, that extra hose is yet another item to be added on to gear, but I guess it’s just one of those things that you eventually get used to and will come to appreciate.

I guess you could always just orally inflate. Are there pros and cons to this? I don’t think anyone’s mentioned this aspect.

I can't remember if it was discussed here or not either- but it did get discussed at length in another thread I started a number of weeks ago regarding DSMB's. Personally, I prefer to orally inflate. I find it easier, I find I can control how much air I am putting in and it just works well for me.

 

[Dogbowl]

I can't remember if it was discussed here or not either- but it did get discussed at length in another thread I started a number of weeks ago regarding DSMB's. Personally, I prefer to orally inflate. I find it easier, I find I can control how much air I am putting in and it just works well for me.

Thanks, I’ll do a search for that thread.