DIY Dive Flag w/milk crate and inner tube

[Aaron Lambright]

Hello.

Since being lock in doors for the foreseeable future I started cleaning out my garage. I came across an old inner tube and decided to make a dive flag. I have a milk crate and the flag itself. I've tested the inner tube, still inflate to 30+ psi for almost 10 days. I've hacked an old hockey stick to about 30", give or take, for the shaft. I think I'm ready to start putting everything together. My question, for those who stuck with me, where is the best location for the tube? Upper third of the the crate? Middle third? or bottom third. I was thinking upper but after reading some other thread I'm not sure. There was some mention of greatly increased drag from the submerged portion of the crate?

Can't wait to hear some constructive comments!!

 

[Johnoly]

.. There was some mention of greatly increased drag from the submerged portion of the crate?....

I'm guessing you have a truck tire size inner tube since the internal diameter would be large enough to hold a standard milk crate. Probably the biggest factor in drag is the surface water tension against all the submerged square inches of tube rubber. The less water contact, the greater the speed of the float (similar to boat hulls). Wind would also be a factor on increased drag, but if diving in a quarry you may not have any. Just a guess, but I would set the milk crate as high out of the water as possible. By running your reel line from the center of the milk crate it should offer the best stability. But in the end it's the water surface tension that creates drag.

As an example, we are spearfishing divers. We use the Rob Allen, solid foam, no crush, Torpedo floats. They attach from the point of the torpedo and sit very high out of the water so minimal water surface contact. The torpedo shape also helps it's "tracking" so wind drift is less but not eliminated. Since the RA floats run about $150 (no line / reel either), your inner tube on a cost benefit basis surely beats my setup.

Build it, Dive it, Change it, til you like it, nice DIY project !!

 

[Aaron Lambright]

Great input Johnoly! It is a good sized tube, just fits around the crate. I'm leaning towards the upper. I'm a casual diver, we don't swim around all that fast, so with your insight on the tube being the major factor with the drag, I'm thinking the lower it sits in the water, the stable. Diving inland lakes in Michigan, you get a lot of boat wakes, so stability is big.

I like you last comment. I can always tweak it if one way doesn't work so well!!

 

[abnfrog]

you only need a car tube I use them all the time when teaching gear stripping . how high it sits in the water depends on the rope loops around the tube and how much you over fill the tube

 

[rhwestfall]

rigging a milk crate to a car/truck tube is common, and just make it work. Personally, I hate them, but diving with them in a 3+ knot current is a disaster with them as they tow you like being tied to a boat. In the quarry, or "calm" waters, they are fine!

YMMV

 

[abnfrog]

I agree but in teaching they are invaluable for putting gear in..i wouldn't want to tow one in a current that's for sure

 

[dead dog]

My question, for those who stuck with me, where is the best location for the tube?

In the water.

 

[Aaron Lambright]

+90% of my diving is in inland lakes. I have more issues with boaters driving up to my inflatable dive buoy and picking it up, thinking it's someone float, as opposed to being pulled by current or wind.