Hi Max,

First off, I am NOT a mechanical engineer, nor have I ever slept in a Holiday Inn Express... (grin)

I can't read the dimensions on that Crosby shackle, but seems that the slot would only have to be about 5/8" high, and only slightly longer than the 'diameter' of the part that captures the pin... Simply slide the jaw of the shackle through the slot 'edgewise', if you know what I mean - in the same fashion you'd pass a bow shackle through the slot in an anchor... The determining factor to how much material can remain around the slot, is the width of the shackle - and I believe most shackles are sized with such an attachment in mind, that they will always allow this sort of passage through an attachment point of the same material...

It's a good idea to try to do it your way, but then what are you using for your bridle? Is the width of the shackle's jaw sufficient to accommodate whatever size thimble you might be using? Or, might you have to employ 2 shackles, pin-to-pin, to make it work?

I was thinking of doing the same thing you are, when I first started out... But, my bridle is a pair of Yale mooring pennants, which use the heavy duty stainless thimbles with the higher sides than ordinary thimbles (the type you definitely want to use for this application, IMHO) And, the only type of shackle that will work with those eyes, is an appropriately sized bow shackle. I didn't like the idea of using 2 shackles, so I simply went with an oversized chainplate, allowing a margin for the pin to work a bit within the hole, as the boat yaws...

Don Jordan's recommendation on the bridle length is determined by the width of your transom, if memory serves... But what I thought was more important for me, was sizing the bridle so that each leg was IN LINE with the angle of the hull at the corner of the transom (and thus, the chainplate), when the bridle was taut (in the same way a chainplate should be in line with the angle of your shrouds, in other words)... Happily for me, the length of my bridle as recommended by Jordan coincided with the length that maintained that angle, anyway...

Hope this helps, and that all this remains a strictly theoretical exercise, and you never, EVER, have to use your drogue... (grin)

best regards,

Jon