How to practically measure float bouyancy

The 100lbs scale would be much more accurate. Many scales are not accurate at their extremes especially as they get older. I would not be surprised if your float pulls a good bit over 50 lbs and the scale simply doesnt read it properly. If you have some gym weights you could get a rough estimate of the buoyancy and check your scale.

When I asked about the bladder dimensions that was an error on my part. I was trying to refer to the portion of the float that actually inflates. The dimensions you gave me seemed like overall dimensions and there appears to be at least an inch in all directions that does not inflate.

For the RA specs I simply used the volume 11L and 9L and calculated the buoyancy in saltwater. The displacement of the 11L float was approximately 24.5lbs of saltwater so subtract the weight of the float with the lead part and account for the fact that it was fresh water and the 20lbs you measured is pretty close. Then I just found the displacement of the 9L float which was a little over 20lbs of saltwater.

Im having trouble calculating the volumes of aimrite floats because they arent a simple shape. Ive tried modeling them as simple cylinders but that produces buoyancies far in excess of what they are rated for. That being said I dont think there is a reason they would be overrated and I think they have the volume to produce that kind of buoyancy. As for your float I would say the reading you took was off.

Actually, the equation I gave earlier is correct. If you got 80 lbs of lift in freshwater and given that the weight of freshwater is 62.2 lbs per cu ft and the weight if saltwater is 64 lbs per cu ft (dependent on the actual salinity of the saltwater) then:

80 lbs lift/62.2 lbs per cu ft = Y lbs lift/64 lbs per cu ft
(64 lbs per cu ft *80 lbs lift)/62.2 lbs per cu ft = Y lbs lift
5120 lbs lift sq per cu ft/62.2 lbs per cu ft = Y lbs lift
82.315 lbs lift = Y lbs lift

so yes, about 2 lbs different.

Dennis

Sorry Dennis I wasnt referring to your equation. I was referring to the one posted by Ladvr

Quote from ladvr

Buoyancy = weight of displaced fluid

The one you posted is correct and is just a simple ratio.

I will not refer to the calculation, I am not spearfishing in blue, I am very ignorant in this, only give my opinion, but I am a fisherman, the matter is the same, drowning the fish, bungies avoid tearing the fish, the design of the buoy (buoys) will do the rest, you can add a acsesorio (acsesorios) to the buoy, tied to the mother of my wife, type anchor or parachute floating, sinking and starting strong with the fish become active accessories. in any case: that is more difficult to dip? a buoy air? , A solid float? use the water element against the fish?, another case the system has to be comfortable to carry in the Water, boat, car .......

in step (bungie - buoy) should be an appropriate configuaración

in step (buoy (s) - acceosriosbuoys), the design of the buoy is exceeded by force of the fish, must be enabled accessories (the mother of my wife).

Quote from Dan

Que quieres decir, suegra? Como se aplica en esta situacion?

suegra = mother of my wife
something difficult to overcome, indefatigable :laughing:

The accessory attached to the buoy should not be hydrodynamic to dive, but if, for desplazarce by surface

awesome...just like John's BW float rig that collapses into a T

Quote from LunkerBuster

awesome...just like John's BW float rig that collapses into a T

so is, I'm not discovering anything

trying to put a grain of sand

They are very generic approaches.

2 buoys do better together.

The idea is something: light, compact, maximize strength, economic, practical, functional.

simple and dynamic system.

Looks like seamen to me:laughing3:

thought i'd repost johns float rig here just for comparison

Depending on the amount of flotation the ''sea brake'' system makes, the use of a bungee is a good choice if large fast fish are targeted. The small signal flare parachutes Maas, Prodanovich, and myself tried years ago put too much load on the fish's meat and rigging.

Cheers, Don

Quote from Dan

The float material has a 3 layer construction; Thermoplastic polyurethane / Nylon / Thermoplastic polyurethane. This material is used in the manufacture of inflatable rafts. Thermoplastic polyurethane is referred to in the industry as TPU. The glue used in the construction is TPU specific.

Wow. Good stuff. Are the seams RF welded or all glue?

I handled this float the other day at Speardiver HQ and was surprised at the construction. I almost expected it to be like air mattress quality at first but when Dan brought it out for me to see and then hold I was shocked. It has some mass to it the material is thick and reminded me of a white water rafting type tube. The overall construction and material was much better/nicer than one Dan had there from a competitor, perhaps he will chime in on which float it was.

^at 0:36 if you look close you see a big cobia swim by :@