WILDTHING TAZ

The First Set Of Test Reports Came Back Today From Herron Testing Labs In Cleveland Ohio. I Sent A Oem U-bolt To Be Stretched With The Nut On It To See How Many Lbs To Would Fail At.

Oem Bolt Has A Formed Thread ( Not A Cut Thread) Which Increases The Strength Of The Thread. It Failed At 8950 Lbs & 8800 Lbs. The Body Of The Bolt Broke. Od Of U-bolt Being .345 In Dia. In 316 Stainless.

We Made A .375 Dia U-bolt(316 Stainless) With A Cut Thread. It Failed At 8300 Lbs & 8750 Lbs. The Nut Stripped Out.

We Made A U-bolt Out Of 17-4ph Annealed It Failed At 13100 Lbs & 13250 Lbs. The Nut Stripped Out.

What This Tells Us Is The Smaller Dia Oem Bolt Weak Link Is The Dia. Of The Material. Because The Nut Never Stripped Off The Roll Formed Threads. The Larger Dia. U Bolt With Cut Threads The Threads & Nuts Failed At The Same Time Making The Bolt Weaker Yet. Using 17-4 Material The Increase In Lbs Is Much Greater(4300 Lbs More). But The Nut Is Still The Weak Link.

All Of These Tests Were Done By Pulling Straight Against The Nut With A Washer On It. Not With A Torque Wrench.we Are Sending 316 Stainless & 18-8 Nuts To The Lab To See What Torque They Fail At. I Have Found That They Will Fail At Approx 53 Ft Lbs My Self. Oem Instructions Tells You To Torque At 53 Lbs. At This Point The Nut Is Maxed Out From The Beginning!!!!

We Can Make A Nut Out Of A Material Called Mo Nell. This Is A Exotic Material Used In Alot Of Government Projects That Require Strength And Corrosion Resistance Applications.Who Knows How Much Total Strength We Will Get With This Nut,And 17-4ph u-bolt. Much More Than 13250 lbs.!!!!

after A Few More Tests I Think A Monell Nut And 17-4ph Material U-bolt I Can Surpass The Oem U-bolts So Much We Will Not Have Any More Problems With Gimbel Rings Loosening Up.if This Works It Will Take Approx. 6 Months To Have Any Thing On The Market For Sale.
Ron Bender

formula31

try a longer nut too. Somtimes that will help by increasing the load distribution. How about a 440C, I happen to have some for nuts and the u-bolt. Let me know. good for freshwater I would think.

formula31

Actually, I think the 17-4 bolts and 440C nuts would be the deal. 440 bolts would be too brittle. you need some stretch to hold a good torque.

WILDTHING TAZ

Only Problem With 440c Is It Will Rust & Corrode. Fresh Or Salt Water. The Tensile Is Not Much Better Than 316.

Tensile Strength
316 Or 18-8 ( 75-115)
440c (110)

I Don't Know What Monell Is But The Nut Mfg. Tell Me It That It Will Take 80 Ft.lbs Of Tourque. When 316 Or 18-8 Takes 53 Ft Lbs.

KAAMA

iTrader: (1)

Ron, how often do the U-bolts fail on a Bravo One? Also, does horse power have that much effect on the U-bolt that you know of ? Thanks

Mark/KAAMA

formula31

We use 440C in all the slaughterhouses and it holds up very well. Needs a decent polish on it to stop any rust. Monel is what they make the marine staples out of. Never tried it on anything else. We use almost all 17-4 or 440C for anything that needs strength. 300 is crap. 316 or 309 if we dont have to harder it. some 420 works real well too.

WILDTHING TAZ

All The Gimbel Rings That I Rebuild ( Swivel Shaft Area ) Seem To Be Heavy Boats Or Boats With Bigger Hp. Torque Vs. Boat Weight Applies To This Just The Same Way A Bravo Drive Blows Up From Torque And Weight And Hp. I Don't See A Line That I Can Draw In The Sand. The Only Reason Swivel Shafts Loosen And Slop Out The Top's. Can Only Be From The U-bolt Or U-bolt Nut Stretching. Thats Why Mercury Says To Re Torque 3 Times A Year. If You Look At Your Gimbel Housing AND Picture How It Works And Which Direction The Forward Pressure Is Directed, You Will Understand What Is Happening. The Go Fast Boats That Leap Out Of The Water, Big Hp & Big Torque Will All Fall In This Repair Problem.