Mooring Pennant size

"The time has come" the Walrus said,
To talk of many things,
of sailing ships and sealing wax!

Or at least mooring pennants. I have been told by my mooring servicer, that I need to replace the pennant. If I measured the bow chocks on Valhalla correctly, the opening is 1 inch. That means I could use 3/4 in line. But doesn't the pennant depend on some elasticity in the pennant? Listed breaking strength for 5/8" 3 strand nylon is 8900 lbs in the table I am looking at. That's not even 2 x the displacement. 3/4 is listed as 12780 lbs. Which one is the better choice. I plan on doing my work. Then I have no to blame if a splice lets go. I have been splicing for years so that's not (or maybe knot) the issue.

I can't find any recommendations, so what is the collected wisdom of the group.

Valhalla is not yet in but headed that way...Yea!!!

John / WA1JG

John - I use a 1/2" mooring pennant, 12' long, which was originally put on the by my mooring guy.

When he recommended replacing it, I added a new one of the same dimensions. Now I've got 2, one coming through each chock, and try to "stress" the old one (i.e. make it the tightest so it gets most of the wear) and use the newer one as the "secondary".

Been working pretty well for a few seasons now and the newer one is barely wearing. Although, the pennants will be getting a good workout this year since I'm in a new location which is much more exposed than where I was previously.

After talking with my mooring maintainer (who knows the boat and the mooring location, ) I am going to use 5/8" nylon line. I am in a fairly protected area. In our harbor, or at least in our area, the moorings do not have a ball. but are pennants shackled to the mooring chain. The boat end of the pennant has a pickup on it. It gets real shallow real quick on the shore side of my mooring so I am going to use a 12 ft pennant.

Now if anyone has a solution to the weather we seem to be still having. If the weather continues, Valhalla is going to get bottom paint and a big splash. This weather is for the birds, or at least seabirds.