Anchor pivot design

[LongRange]

I would like to construct a stainless steel pivot with two rollers to put in place of the existing single (non-pivoting) roller on our small bowsprit. The reasoning:

1) The 33kg Rocna does not self-launch right now. With the current (flat and static) anchor roller geometry, loosening the chain does not by itself launch the anchor. Instead, it is necessary to give the anchor a small shove.

By pushing the Rocna an additional 10-30cm outboard, courtesy of the new pivot, I hope to make the anchor truly self-launching.

2) In the absence of a pivot, the load on the single roller axle looks truly ginormous as the shank of the anchor rounds those first few centimeters over the roller, either on its way up or down. The entire bowsprit looks like it is about to get torn off.

The pivot should drastically reduce those loads, because there is never a situation where 32.5kg worth of Rocna is supported by the last 2cm of its shank.

3) The near-plumb bow of our Dufour 455 GL means that even with the little SS bowsprit the big Rocna is aways in danger of tearing chunks of fiberglass out of the lower stem near the waterline - the portion not protected by SS stem armour.

I am hoping that the presence of the pivot will push out the anchor a few precious additional centimeters further away from the stem.

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We always use a snubber tied to a cleat, so the pivot does not need to cope with storm anchoring loads.

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What are some of the elements of pivot design I should be aware of? I have not been able to find much information on this topic.

Should the inboard and outboard arms of the pivot be of equal length, or does it depend on the specific setup?

How long should the pivot be overall, in proportion to the shank of the anchor?

Should both rollers be the largest diameter that's practical, or is there an advantage to having the inboard (aft) roller smaller?

All info and suggestions will be greatly appreciated.