The new Freedom Contour - The Rolex of backplates.

[stuartv]

Glad you mentioned that! I just got out my digital luggage scale and weighed mine.

My size Large Freedom plate weighed in at 5.16#. I checked it several times and it always settled in at the exact same number.

I have not performed a calibration on my scale, but I've used it to weigh a number of fins in and out of the water and it produces very consistent and very believable numbers, so I'm guessing 5.2# for the Large FCP is pretty accurate.

 

[stuartv]

I'm confused. A carriage bolt has a domed head and a square extension under it before transitioning to the shank or thread:
View attachment 428208

It sounds like you are describing a Button Head Socket Cap Screw, Flanged Button Head Socket Cap Screw, or maybe a Hurricane Bolt.

Stainless carriage bolts are fairly easy to get in lots of different lengths but the others are less available in the 5/16" to 3/8" range typically used on double bands.

My bad. Yes, you are correct. I knew I wasn't using the right term, but I was too lazy to go find a picture and use the correct term. I really meant a Button Head Socket Cap screw.

I think those should (?) be easy to find in the length that would go through the BP and into the doubles adapter (or STA).

 

[lowviz]

@Francesea

WOW! That finish took hours after working it into shape!! (love to know how many hours at the wheel...)

I am using SS fill rod, flap sander, gray compound to cut, and yellow compound to color my FP. I have an old unfinished one that I love. Works just fine as is, but she will shine again!

I'm guessing Eric goes even further with polishing than I do. Love to know your final compound, @Eric Sedletzky ....

 

[stuartv]

I was hoping that post would suck you in!

If only it were that simple. There are 5.25, 6.9, 7.25, and 8" OD cylinders on 190 and 215mm manifolds. Then there's valve up and valve-down. I have computer models of all of them. You also have different preferences and body geometry that you can't model. That is why I suggest using spacers between the adapter and bands. That lets divers tweak it to find their own sweet spot.

The Freedom Plate is great for people that aren't satisfied one-size-fits-nobody.

I finally "get" you on the spacers you're talking about four doubles.

So, why not make the doubles adapter an inverted T, where the crossbar (at the bottom) is wide enough to reach the tank centers for 8" cylinders on a 215mm manifold, and thick enough (or with plain spacers mounted) to hold the bottom of any cylinder the right distance from the tank?

Okay, I'll shut up on this now. Between you and Eric, I'm sure you do not need my "helpful" (in the loosest sense of the word) suggestions.

 

[Akimbo]

The Freedom Plate needs to sit against your back slightly more than the cylinders along side your back otherwise the whole concept of the form fitting benefit of the contoured plate is lost. In order to do this the plate must levitate out a bit from the tanks so that the plate can "sink in" where it needs to be on your back. This creates a stability problem with the mounting system and tanks...

To illustrate, here is an image from a Voit catalog of their Snug Pack mounted to double 50s. Imagine longer cylinder that will rest against your butt and you can see how it will sit in the small of your back:

Here is the catalog sheet:

I used these for years on double and singles. They were very comfortable and stable but larger than necessary to do the job. They were also different injection molded ABS packs, identical near the perimeter but different in the recesses. I still have one of the doubles bands... it was just too elegant of a design to toss even though the back packs themselves are in a landfill somewhere.

The largest rig I used them on was double steel 72s (2250 PSI) but there was only a single 5/16" bolt holding the pack to the doubles band. I cracked the ABS single pack and repaired it with a layer of fiberglass on both sides. They came with 2" cotton webbing and three snaps at the left shoulder.

As a point of reference: I just used two 1/4-20 flatheads on the homebrew doubles adapter I used on the Aluminum 80s in Truk. I think it would be easy to come up with a bracket that took most of the weight and just used one or two bolts to lock the plate the the adapter. Will you be in Mendocino anytime soon?

 

[stuartv]

@Francesea

WOW! That finish took hours after working it into shape!! (love to know how many hours at the wheel...)

I am using SS fill rod, flap sander, gray compound to cut, and yellow compound to color my FP. I have an old unfinished one that I love. Works just fine as is, but she will shine again!

I'm guessing Eric goes even further with polishing than I do. Love to know your final compound, @Eric Sedletzky ....

LOL When I took mine out of the box, I (very, very briefly) contemplated breaking out the tools and polishing the back to match the front. Then I remembered how much I like barracuda who like shiny stuff.... I decided it's perfectly bee-yoo-tee-ful just as it is.

 

[Akimbo]

So, why not make the doubles adapter an inverted T, where the crossbar (at the bottom) is wide enough to reach the tank centers for 8" cylinders on a 215mm manifold, and thick enough (or with plain spacers mounted) to hold the bottom of any cylinder the right distance from the tank?

That would be too big for smaller sets like LP-50s (5¼" OD) and 190mm centers. IMHO, having everything mount to the doubles band would be the most compact, simple, and universal approach... but I'm always open to other ideas. Spacers also allows you to adjust the standoff distance to your liking... top and bottom. Some people have very deep recesses at the small of their back while others are a near-vertical spine and no butt. You can see how the pack can transfer a lot of weight on deck to your hip, which helps for stability and comfort.

 

[Akimbo]

I think those should (?) be easy to find in the length that would go through the BP and into the doubles adapter (or STA).

It is easy find in black chromate steel but really limited in stainless. Stainless is pretty soft so the the allen-head recess will round out much faster than on steel. I'm sure that is one of the many reasons that Eric is putting square holes in the plates (for the carriage bolt).

 

[Akimbo]

LOL When I took mine out of the box, I (very, very briefly) contemplated breaking out the tools and polishing the back to match the front.

The wing pretty well hides the back anyway so buff away. My wife is amazed how I prefer polished stainless over her gold jewelry... must be a "guy" thing.

 

[stuartv]

That would be too big for smaller sets like LP-50s (5¼" OD) and 190mm centers. IMHO, having everything mount to the doubles band would be the most compact, simple, and universal approach... but I'm always open to other ideas.

I would be most interested in a solution that would allow me to use, for example, some doubles I just rented. And also let me still use my doubles with the FP and with a regular plate. All without any significant amount of wrenching. Definitely nothing that requires any changes to the tank bolts where they attach to the bands. Those are a pain to get positioned right and with the right amount sticking out. And, preferably the solution would require no more tools than just a hex wrench for the cap screws. But, maybe that just isn't possible.... Or maybe there needs to be a piece that goes at the bottom, to act sort of as a cradle/spacer for different sized tank, with 2 or 3 different sizes to cover the range of tank sizes and spacing.