Split Handles

[Slidewinder]

Perhaps its a model C difference but I'm not sure what you're referring to and didn't notice any problems the shackle might hit

No, not a Model C difference. From your posted photo the chain swivel connector appears to be about 10" forward of the handgrips. With the stock handle the handgrips are up much closer to the swivel connector. Your set-up is fine if you have that forward clearance to the uprights at the catch, but for those with a longer reach the swivel connector and shackle will end up between the uprights holding the PM. For those users it would be like threading a needle on every stroke. In that case the fix I described is required.

[Slidewinder]

Elbows down does keep the wrist straighter but doesn't keep my wrists from popping. Split handles it completely goes away and there is no choice but for the only forces on the wrist to be a straight pull

Absolutely. Hands, wrists, and forearms in alignment with the direction of applied force. Your set-up (and mine) ensure this. The C2 stock handle doesn't. It is a design deficiency.

[nates]

Ah I've got plenty of space left at catch. This is actually as far forward as it goes with my butt on the seat and a hand on the handle

[stevegaspars]

You'll be wanting the brass swivel bush on the other side of that D shackle pin.

[Sakly]

You'll be wanting the brass swivel bush on the other side of that D shackle pin.

I think there is no need for the brass swivel bush in this setup at all. Mainly it shall prevent a wear and tear due to the U-shape of the handle connector and the handle movements, but in this setup it is a straight bolt from the D shackle, which will create much less wear and tear, if at all.

[nates]

I had to move it because it blocked the d-shackle. I suppose I could have used a larger one to clear the bushing but I was ready to get back on the sled.

[JaapvanE]

You'll be wanting the brass swivel bush on the other side of that D shackle pin.

I think there is no need for the brass swivel bush in this setup at all. Mainly it shall prevent a wear and tear due to the U-shape of the handle connector and the handle movements, but in this setup it is a straight bolt from the D shackle, which will create much less wear and tear, if at all.

Sure about that? It is a steel on steel connection, which is always suspect in my book.

[nates]

I took some measurements and the bushing OD is 20.5mm and the max pin size is 10mm. A 3/8 d-shackle would fill the hole (less slop) but standared size 3/8 seems to have a clearance width of slightly less than 20mm, so it'd need to be a wide one. Still looking for a no-snag wide 3/8" d-shackle, but that'd be the ticket to allow the bushing to stay in its place doing its job.

[Sakly]

You'll be wanting the brass swivel bush on the other side of that D shackle pin.

I think there is no need for the brass swivel bush in this setup at all. Mainly it shall prevent a wear and tear due to the U-shape of the handle connector and the handle movements, but in this setup it is a straight bolt from the D shackle, which will create much less wear and tear, if at all.

Sure about that? It is a steel on steel connection, which is always suspect in my book.

Very much, but not definitely
If you remove the brass swivel bush, the U-shape of the handle connector only has connection points left and right, steel on steel. So the force transfer is happening on a very small surface area AND the U-shape connector will move with the handle movement, if you pull not strictly parallel, so this creates shearing and even higher load on these small surface areas.
Both is not happening with the new setup. The bolt of the D shackle is straight, so had much greater connection area and it is not moving at all, when pulling on the handles.
The new point of shearing load is created at the D-shackle and the handle connectors.

[nates]

Most of what was turning up was either way to wide or stupid shipping prices, but I found a reasonably priced 3/8 d-shackle that's about 20.1mm. I measured 20.5mm OD, but I have ways of making metal fit. Actually if I can just hammer it on - it doesn't really need to pivot freely since it's free to move at either end.

[Slidewinder]

Ah I've got plenty of space left at catch. This is actually as far forward as it goes with my butt on the seat and a hand on the handle

That's fine, but you do understand that it could be a problem for those with a long reach at the catch? My advice was intended for others who want to try a similar set-up to yours. If they have a long reach at the catch they will need to remove the two vertical struts on each side of the chain port to provide clearance for the shackle and associated hardware so as not to impede their reach and cramp their form. The PM must then be mounted elsewhere. The C2 handle clip location works well. The existing PM cable is long enough to reach, and the bolts and bolt holes are already there to secure a simple DIY bracket to hold the PM.

Also for those who want to try a similar set-up: I have found through experimentation that 11"-12" from the centre of the handgrips to the front pivot of the 'V' is optimal. The resulting angular progression of the handgrips as the stroke progresses and the 'V' opens, closely matches that of the grip of sculling oars during the latter half of an actual sculling stroke, and simultaneously and fortuitously maintains alignment of the hands, wrists, and forearms throughout the stroke.

Years ago, I replaced the straps, carabiners, and shackle of your set-up with left and right rigid pivoting linkages, and rotatable handle brackets at the distal ends - both for aesthetics and to render the assembly less 'loosey-goosey'. It provides a greater sense of stability, like having oarlocks with your oars. Infinite planes of rotation are not required, just three - one about the front pivot, and one for each of the handle brackets. The centre of the plane of rotation of the handle brackets should be in line with the centre of rotation of one's wrists. Also, the handgrips should not be fixed at a right angle to the forearm, but tilted forward slightly - like the relationship of a pistol grip to the barrel. It is useful to think about it in this way - as two long barrelled pistols pivotably joined at their muzzles such that regardless of their orientation - vertical, horizontal, or anywhere in-between, the ergonomically correct hand, wrist, forearm relationship is always maintained.

Unfortunately, I am not allowed to post a photo of my set-up. The moderator fears that it will burn the eyes of C2 Forum members if they were to behold it. Only photos of cobbled together handle assemblies are permitted here.

[Sakly]

Unfortunately, I am not allowed to post a photo of my set-up. The moderator fears that it will burn the eyes of C2 Forum members if they were to behold it. Only photos of cobbled together handle assemblies are permitted here.

Why shouldn't you be allowed to post a picture of your setup?
I am very sure, I've seen your setup in some other thread in the past, but probably it was a link to elsewhere.
As this forum has stupidly rigid rules for picture sizes, you need to host them on any random external host service and link them with BB code in your post. This works well and shouldn't give you any problems.

[Slidewinder]

Why shouldn't you be allowed to post a picture of your setup?
I am very sure, I've seen your setup in some other thread in the past, but probably it was a link to elsewhere.

About 15 years ago I posted a photo, but more recently when I did, it was quickly deleted by the moderator.

[nates]

If I can delicately summarize. The hostility at this point is more about the personalities and history than the idea. The moderation is due to perception that Robert is hawking a product on a manufacturer's forum. Was that fair by both sides?

As for the uprights, in actual use it can just enter the uprights with my arm length and catch, but it's well centered. Actually I get occasional rubbing on the phone holder if I'm pulling too high at the catch, but that's not unique to my handles.

I took the snap caribiners out to reduce the length but i was getting more shoulder action with the extra length

[JaapvanE]

Very much, but not definitely

As my manager typically says: if you aren't sure, mitigate. I'd agree the contact surface is less stressed under perfect conditions in the new setup, but under assymmetric load, I wouldn't be sure.