Bouyancy bags?

C

chrisfsi

New Member
Hello all

First post and all that - am replacing a (leaking) inspection hatch, and have encountered 3 (possibly more) sealed, heavy duty plastic bags inside the hull. These I assume to be bouyancy bags. Is this correct, and are they supposed to be there? I can't find much of a reference to them on the site - but am possibly just not looking in the right place. How many should there be?

Apart from that, great site - keep up the good work!

Thanks

Chris
 
Yes, those are supposed to be there. I am not sure how many. I think 3 in the front and two in the back, but that is a guess.
In any case do not take them out. They are in the hull to prevent a titanic-like event. Do check them for leaks (just press on them, if they do not deflate your fine) and for any water in them. They are easy and cheap to replace.

GWF
 
Are they plastic garbarge type bags that have hard objects like chunks of foam inside of them or do they look like 5 gallon water jugs? Older boats had the foam that over time will get waterlogged and you should replace them with the cubetainers as they are called. Your local Laser dealer should have them readily available.
 
Are they plastic garbage bags with soft yard clippings like material inside? According to the rewritten legendary Laser lore, some of the older boats were alleged to return from foreign regattas with extra cargo and sometimes the sailors were slightly impaired and tended to lose track of stuff?????

Of course I wouldn't really know anything about that sort of stuff as back then I was a good kid who sailed Sidewinders and only ventured across Lake Erie with my girlfriend to buy fireworks.
 
Thanks to all for replies - they look more like transparent 5 gallon containers, screw on lid. No foam - so sounds like I have the current technology, so to speak. Will leave them in and try to avoid icebergs....
 
Fishingmickey,

Great for those days with no wind: just stick your nose in the inspection port and the frustration will slip away!

GWF
 
chrisfsi said:
Thanks to all for replies - they look more like transparent 5 gallon containers, screw on lid. No foam - so sounds like I have the current technology, so to speak. Will leave them in and try to avoid icebergs....
Click to expand...

They are called "cubitainers" or "cubicontainers" and there are supposed to be 3 big ones in the front and 3 little ones in the stern, although they do migrate around, as they are not anchored in place in any way. I opened up my front inspection hatch, saw none, and thought "gee, the last jerk must have thought he could save a few ounces by taking them out..." and bought replacements and put them in. Some time later I opened up the stern and found all the cubitainers that the boat is supposed to have, back in the stern behind the cockpit.
 
Chris123 said:
They are called "cubitainers" or "cubicontainers" and there are supposed to be 3 big ones in the front and 3 little ones in the stern, although they do migrate around, as they are not anchored in place in any way. I opened up my front inspection hatch, saw none, and thought "gee, the last jerk must have thought he could save a few ounces by taking them out..." and bought replacements and put them in. Some time later I opened up the stern and found all the cubitainers that the boat is supposed to have, back in the stern behind the cockpit.
Click to expand...

Here is one for the physicists: Will having more cubitainers make your boat float higher in the water? And give you an advantage (less wetted surface and higher sail plan to catch a puff)?
 
Wavedancer said:
Here is one for the physicists: Will having more cubitainers make your boat float higher in the water?
Click to expand...
Not unless your boat has a major hole in it and is full of water. Then it would float 'less low' than with standard flotation bags.

I know of a couple of Solings at the bottom of the lake due to no flotation in the hull.
 
Well, I'm not much of a physicist, but I reckon the answer is NO - if anything, it will float a nanometer lower. Reason is, the total volume of the inside of a hull is fixed. With no bouyancy bags, all you have inside is air. (assuming no leaks, in which case you'll have a bit of water as well... ;-) ) WITH bouyancy bags, all you've done is replace a miniscule volume of air with the total volume of the plastic required to make the containers. And as the plastic has a higher density than the air it is replacing, it will float an un-measurably smaller amount lower.
 
If you have ever held on tothe string under a helium filled party baloon you know how hard that baloon pulls upward.

The Party baloon empty weighs a lot less than the plastic water jugs the builders stuff in Lasers.

There is a pretty good chance a helium filled water jug weighs as much as the surrounding air
 
gouvernail said:
If you have ever held on tothe string under a helium filled party baloon you know how hard that baloon pulls upward.

The Party baloon empty weighs a lot less than the plastic water jugs the builders stuff in Lasers.

There is a pretty good chance a helium filled water jug weighs as much as the surrounding air
Click to expand...

I believe I've quoted this before, but from a bicyclist friend: "Yeah, you could theoretically save weight by filling your tires with helium, but you'd save about as much weight by shaving off your eyebrows, which would also cut down on wind resistance and be a nice conversation starter too."

So look for the sailors with the shaved eyebrows at the next regatta, and for the measurer with a portable helium detector.
 
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