Please see this article in the REFERENCE section for advice on how to replace the rub rail on classic-era hulls:
Rub Rail Replacementhttps://continuouswave.com/whaler/refer ... bRail.htmlThis article is also mentioned in the FAQ. See
Q13: How are Rub Rails Replaced
https://continuouswave.com/whaler/reference/FAQ/#Q13Also: the prices for replacement tracks and vinyl inserts have increased significantly. The days of the "$100" rub rail kit are over. I will have to update the reference article to reflect that.
Also: note that the "three-piece" rub rail mentioned is only for the SPORT 15 hulls. A larger hull like an OUTRAGE 20 would just have two pieces, a molded track and the vinyl flexible insert.
I do not know the exact part numbers for a c.1988 OUTRAGE 20 hull as shown on the vendor website FNO (Frank) mentioned. Cf:
https://www.integritymarinecorp.com/rigid-rubrails-with-flexible-inserts?Category=Boston%2520WhalerIf you measure the height of the rub rail molding you should be able to figure out the part number; then you can get the part number for the flexible insert from the molded track specifications.