Thanks for the offer. My M-15 aft cleat measures 5 and 1/8" tip to tip, black anodized, not painted. If this is the same cleat I only need to buy one. Can this work? Let me know. My cleat has the mark CW, with the C superimposed over the W..... ---Thanks Larry.
Rigrite www.rigrite.com seems to have some wc cleats around the size your looking for, called spar cleats I think.
5" Deck Cleats Deck Cleat - 5" long, Black: Sch 70-05X: Cast Aluminum Deck Cleat is a low-profile design with a narrow base suitable for use with line up to 3/8" diameter. Black epoxy coated Cleat is 5" long, and fastens to Deck with (4) 7/32" (#12) FH screws on 1 1/4" (fore and aft) x 1 3/8" (athwartships) hole centers. - Limited Availability. Larry, This looks like the cleats that I have, except that the athwartships hole centers are 1 1/2" instead of 1 3/8". The black anodizing has long since worn off. In fact, I had no idea they had been black at one time until I took a closer look to see if they matched your description. If you want a black one, looks like you can get it at rigrite, or I'll make you a good deal on one of mine, depending on which one matches your measurements. Larry Y