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Author Topic:   Safety Torque Hub kit

mikemdd posted 12-15-2010 11:22 PM ET (US)
Anyone have any experience with this hub kit?
http://safetytorque.com/
Interesting concept, but very pricy (I think >$300!). Ignoring the price issue, does it have other benefits besides resetting? Prop rattle?

tedious posted 12-16-2010 08:20 AM ET (US)
Interesting idea, wish they had more pictures of the guts. I'd be worried about any dry clutch continuing to function properly for very long in a marine environment.
Tim
pcrussell50 posted 12-16-2010 05:12 PM ET (US)
How do you get an overtorque unless you hit something, like a net that wraps around the prop and stops it? Isn't the rubber inside the prop hub more or less designed to protect the driveline as well? Of course, if you shear the rubber hub, you're dead in the water until you change props. But if you are wrapped in a net, you probably have to take the prop off to free yourself anyway. I'm not sure I get the bottom line usefulness of this thing.
-Peter
jimh posted 12-22-2010 07:50 AM ET (US)
The animation shown in
http://safetytorque.com/?learnmore
gives some details of the internal construction of the device.
adlert posted 12-22-2010 09:14 AM ET (US)
This is not a new idea. At least one of the very old outboards I have in my collection contains a protective clutch mechanism in front of the forward gear. I think it's the '56 Elgin. I remember it as a really sweet system in that as configured in that engine, it doubled as the mechanism used for engaging/disengaging forward gear. In addition to added driveline protection, it offered very smooth, positive, and quiet forward engagement. No clunk or ratcheting associated with today's "clutch dogs."
Straying off topic a bit but I've gotten myself wondering when or if outboard engines will ever employ the smoother cone shifting mechanisms common to Volvo and Mercruiser's Bravo line of stern drives. I'd think also that with a little creativity, a protective clutching mechanism could be incorporated too. Then we'd have the it all in a tidy package. Maybe someone is providing these sorts of features? I really don't know.
jimh posted 12-22-2010 11:55 AM ET (US)
ASIDE: If you wish to read more about how outboard engine manufacturers are switching to desmodromic shift mechanisms, see my article from several years ago on this topic:
http://continuouswave.com/ubb/Forum1/HTML/015209.html
adlert posted 12-22-2010 01:40 PM ET (US)
Thanks for the link Jim. I actually have hands-on experience with many, if not all, of the methods used over the years to move lower unit clutch dogs around. In the end, the final engagement in clutch dog based designs are all essentially the same and similarly crude.
I really don't mean to pull the discussion off the topic. However, watching the "Safety Torque Hub Kit" video I couldn't help but notice the similarities between their mechanism, an old Elgin spring-loaded flat clutch-based shifting mechanism, and the smoother and quieter "cone" type shifting system currently used in several stern drive upper gearcases. How easy it seems to me it would be to 1)combine common design features into one smooth shifting drive unit with damage protection, and then 2) offer those features in our beloved outboard gearcases. I envision calibrated, spring-loaded cone-type shifters. Maybe I should give Mercury a call.
Until that time, it seems to me that the hub system offered by SafetyTorque might be good extra insurance against drive-line damage when running steel props in rocky areas. $300 for the unit might seem very reasonable when facing the bill to replace a hopelessly damaged prop plus bent prop shaft, chipped gears, etc. Unfortunately, the rubber hubs in our props don't always slip as easily upon impact as we'd like them to.
adlert posted 12-22-2010 01:57 PM ET (US)
I feel compelled to mention that "desmodromic" type shifting mechanisms have been used in outboard gearcases essentially since F-N-R shifting first became available. I think since the middle to late '40s at least.
jimh posted 12-24-2010 09:24 AM ET (US)
I don't think most outboard gear cases use desmodromic shift mechanisms. Most of them use a spring return type shift mechanism. That situation is why the manufacturer was calling attention to his use of desmodromic shift in the new model.
I don't think there is room in an outboard motor gear case for a cone clutch. In a sterndrive mechanism, the cone clutch is typically located in the drive shaft area above the gear case.
adlert posted 12-24-2010 01:03 PM ET (US)
"I don't think most outboard gear cases use desmodromic shift mechanisms. Most of them use a spring return type shift mechanism."
I don't want to beat this dead horse but your statement above is absolutely incorrect. Essentially all early, and smaller outboards from OMC, Scott Attwater, Oliver (just to name a few) used yokes and cradles to move their clutch dogs back and forth. For OMC certainly, the use of springs is by far the exception to the rule. Their hydraulic-electric shift gear cases of the late 60's, early 70's used springs to engage forward gear but that is about it. Mercury did use them more frequently.
I agree that space might possibly be a problem for cone shifters in a gearcase. But if you hold them in your hand and think about their size relative to the HP they're typically mated up to, I've get the feeling it's doable. We'll see...
contender posted 12-24-2010 01:23 PM ET (US)
Is this [?] not what a hub in the prop is suposed to due? Peter is correct [about what?--jimh].
jimh posted 12-24-2010 03:12 PM ET (US)
I don't consider the discussion of desmodromic shift mechanisms to be "a dead horse," as it has received almost no prior discussion. I believe adlert may be the only one who thinks it is "a dead horse." If the current crop of outboard gear case mechanisms are truly desmodromic, why do they all need return springs?
adlert posted 12-24-2010 06:00 PM ET (US)
Jim, I just thought that discussion regarding desmodromic mechanisms strayed from the safetytorque topic.
Regarding your statement: "If the current crop of outboard gear case mechanisms are truly desmodromic, why do they all need return springs?"
Please note: 1) I never said all of the current outboard gearcases were desmodromic (they aren't); and 2) check out, as an single example, the classic 50 year old push-pull yoke and cradle operated clutch dog in the following 2011 E-TEC 15 HP gearcase.
http://shop2.evinrude.com/Index.aspx?s1=tbdsdmnvp73feuvesphkuboee0&catalog_id=0&siteid=1
In this example, part #'s 32 and 33 are indeed a spring and detent balls, but they are used only to help keep the dog firmly engaged with the forward and reverse gears. The spring is not used to actually push the dog into position; just an improvement added to help keep it there. The dog movement is done via the push and pull of the yoke, cradle, and shift shaft just as it has been done for decades in OMC engines and many others. Sorry I forgot how to make the link active. Time to cook dinner.
Merry X-Mas All!
adlert posted 12-24-2010 06:08 PM ET (US)
I'm thinking even cutting and pasting the address I posted doesn't work. My apologies. If inclined, go to Bombardier's online parts catalog and find your way to a 15 hp gearcase blow-up to see what I'm talking about. Probably other engines will also demonstrate the point.
pcrussell50 posted 12-27-2010 03:28 PM ET (US)
My old '59 Johnson Super Seahorse 35hp has desmodromic, or "push-pull" shifting. Works great. Super simple.
-Peter
mikemdd posted 01-08-2011 09:53 AM ET (US)
Just as follow-up. I'm thinking these may not be ready for prime time yet. I requested more information and have not received any response. Also, these are apparently not off the shelf items. You need to supply all kinds of information about your setup, much of which I have no idea the answer. Apparently, you can't just say you want a kit for a Merc 115HP Fourstroke. Each one seems to be custom to each motor, lower unit and prop. Sounds shakey to me.

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Author	Topic: Safety Torque Hub kit
mikemdd	posted 12-15-2010 11:22 PM ET (US) Anyone have any experience with this hub kit? http://safetytorque.com/ Interesting concept, but very pricy (I think >$300!). Ignoring the price issue, does it have other benefits besides resetting? Prop rattle?
tedious	posted 12-16-2010 08:20 AM ET (US) Interesting idea, wish they had more pictures of the guts. I'd be worried about any dry clutch continuing to function properly for very long in a marine environment. Tim
pcrussell50	posted 12-16-2010 05:12 PM ET (US) How do you get an overtorque unless you hit something, like a net that wraps around the prop and stops it? Isn't the rubber inside the prop hub more or less designed to protect the driveline as well? Of course, if you shear the rubber hub, you're dead in the water until you change props. But if you are wrapped in a net, you probably have to take the prop off to free yourself anyway. I'm not sure I get the bottom line usefulness of this thing. -Peter
jimh	posted 12-22-2010 07:50 AM ET (US) The animation shown in http://safetytorque.com/?learnmore gives some details of the internal construction of the device.
adlert	posted 12-22-2010 09:14 AM ET (US) This is not a new idea. At least one of the very old outboards I have in my collection contains a protective clutch mechanism in front of the forward gear. I think it's the '56 Elgin. I remember it as a really sweet system in that as configured in that engine, it doubled as the mechanism used for engaging/disengaging forward gear. In addition to added driveline protection, it offered very smooth, positive, and quiet forward engagement. No clunk or ratcheting associated with today's "clutch dogs." Straying off topic a bit but I've gotten myself wondering when or if outboard engines will ever employ the smoother cone shifting mechanisms common to Volvo and Mercruiser's Bravo line of stern drives. I'd think also that with a little creativity, a protective clutching mechanism could be incorporated too. Then we'd have the it all in a tidy package. Maybe someone is providing these sorts of features? I really don't know.
jimh	posted 12-22-2010 11:55 AM ET (US) ASIDE: If you wish to read more about how outboard engine manufacturers are switching to desmodromic shift mechanisms, see my article from several years ago on this topic: http://continuouswave.com/ubb/Forum1/HTML/015209.html
adlert	posted 12-22-2010 01:40 PM ET (US) Thanks for the link Jim. I actually have hands-on experience with many, if not all, of the methods used over the years to move lower unit clutch dogs around. In the end, the final engagement in clutch dog based designs are all essentially the same and similarly crude. I really don't mean to pull the discussion off the topic. However, watching the "Safety Torque Hub Kit" video I couldn't help but notice the similarities between their mechanism, an old Elgin spring-loaded flat clutch-based shifting mechanism, and the smoother and quieter "cone" type shifting system currently used in several stern drive upper gearcases. How easy it seems to me it would be to 1)combine common design features into one smooth shifting drive unit with damage protection, and then 2) offer those features in our beloved outboard gearcases. I envision calibrated, spring-loaded cone-type shifters. Maybe I should give Mercury a call. Until that time, it seems to me that the hub system offered by SafetyTorque might be good extra insurance against drive-line damage when running steel props in rocky areas. $300 for the unit might seem very reasonable when facing the bill to replace a hopelessly damaged prop plus bent prop shaft, chipped gears, etc. Unfortunately, the rubber hubs in our props don't always slip as easily upon impact as we'd like them to.
adlert	posted 12-22-2010 01:57 PM ET (US) I feel compelled to mention that "desmodromic" type shifting mechanisms have been used in outboard gearcases essentially since F-N-R shifting first became available. I think since the middle to late '40s at least.
jimh	posted 12-24-2010 09:24 AM ET (US) I don't think most outboard gear cases use desmodromic shift mechanisms. Most of them use a spring return type shift mechanism. That situation is why the manufacturer was calling attention to his use of desmodromic shift in the new model. I don't think there is room in an outboard motor gear case for a cone clutch. In a sterndrive mechanism, the cone clutch is typically located in the drive shaft area above the gear case.
adlert	posted 12-24-2010 01:03 PM ET (US) "I don't think most outboard gear cases use desmodromic shift mechanisms. Most of them use a spring return type shift mechanism." I don't want to beat this dead horse but your statement above is absolutely incorrect. Essentially all early, and smaller outboards from OMC, Scott Attwater, Oliver (just to name a few) used yokes and cradles to move their clutch dogs back and forth. For OMC certainly, the use of springs is by far the exception to the rule. Their hydraulic-electric shift gear cases of the late 60's, early 70's used springs to engage forward gear but that is about it. Mercury did use them more frequently. I agree that space might possibly be a problem for cone shifters in a gearcase. But if you hold them in your hand and think about their size relative to the HP they're typically mated up to, I've get the feeling it's doable. We'll see...
contender	posted 12-24-2010 01:23 PM ET (US) Is this [?] not what a hub in the prop is suposed to due? Peter is correct [about what?--jimh].
jimh	posted 12-24-2010 03:12 PM ET (US) I don't consider the discussion of desmodromic shift mechanisms to be "a dead horse," as it has received almost no prior discussion. I believe adlert may be the only one who thinks it is "a dead horse." If the current crop of outboard gear case mechanisms are truly desmodromic, why do they all need return springs?
adlert	posted 12-24-2010 06:00 PM ET (US) Jim, I just thought that discussion regarding desmodromic mechanisms strayed from the safetytorque topic. Regarding your statement: "If the current crop of outboard gear case mechanisms are truly desmodromic, why do they all need return springs?" Please note: 1) I never said all of the current outboard gearcases were desmodromic (they aren't); and 2) check out, as an single example, the classic 50 year old push-pull yoke and cradle operated clutch dog in the following 2011 E-TEC 15 HP gearcase. http://shop2.evinrude.com/Index.aspx?s1=tbdsdmnvp73feuvesphkuboee0&catalog_id=0&siteid=1 In this example, part #'s 32 and 33 are indeed a spring and detent balls, but they are used only to help keep the dog firmly engaged with the forward and reverse gears. The spring is not used to actually push the dog into position; just an improvement added to help keep it there. The dog movement is done via the push and pull of the yoke, cradle, and shift shaft just as it has been done for decades in OMC engines and many others. Sorry I forgot how to make the link active. Time to cook dinner. Merry X-Mas All!
adlert	posted 12-24-2010 06:08 PM ET (US) I'm thinking even cutting and pasting the address I posted doesn't work. My apologies. If inclined, go to Bombardier's online parts catalog and find your way to a 15 hp gearcase blow-up to see what I'm talking about. Probably other engines will also demonstrate the point.
pcrussell50	posted 12-27-2010 03:28 PM ET (US) My old '59 Johnson Super Seahorse 35hp has desmodromic, or "push-pull" shifting. Works great. Super simple. -Peter
mikemdd	posted 01-08-2011 09:53 AM ET (US) Just as follow-up. I'm thinking these may not be ready for prime time yet. I requested more information and have not received any response. Also, these are apparently not off the shelf items. You need to supply all kinds of information about your setup, much of which I have no idea the answer. Apparently, you can't just say you want a kit for a Merc 115HP Fourstroke. Each one seems to be custom to each motor, lower unit and prop. Sounds shakey to me.