Maintenance - Repairs to keel sump

Print Page | Close Window

Repairs to keel sump

Printed From: Laser 28 International Class Association
Category: Laser 28 General
Forum Name: Maintenance
Forum Description: All the things to care for your boat
URL: http://www.laser28.org/forum/forum_posts.asp?TID=108
Printed Date: 23 November 2024 at 3:48am
Software Version: Web Wiz Forums 11.03 - http://www.webwizforums.com

Topic: Repairs to keel sump

Posted By: Guests
Subject: Repairs to keel sump
Date Posted: 11 March 2006 at 8:55pm

Zapatero has developed cracking in the region of the keel sump. The cracks include a longitudinal crack the length of the keel on the outside of the hull where the sump meets the fairbody (not the sump-keel joint) and some smaller interior cracks in the molded sump/floor grid in the vicinity of the keel bolts and floors. Has anyone done a repair to this area? Also, Bill, do you remember, or can put your hands on the specific lay-up schedule in this area? I believe the hull to be Kevlar-epoxy, cored with pvc foam. Is this correct? Is the molded structural grid also kevlar epoxy?

Replies:

Posted By: Guests
Date Posted: 19 October 2007 at 3:38pm

An update on Zapatero's repair:

Once hauled, we found there were no cracks in the hull laminate, just in some fairing putty and the bottom paint.

The structural grid had become disbonded from the hull for a distance of about 1 foot, either side of the sump. The sump remained bonded and there were cracks that went completely through the grid laminate with a length of an inch or two at the junction between the sump and the transverse beams (floors).

We repaired as follows:

Cut out the structural grid for a total width of about 5 feet and for a distance about 6 inches beyond the front and back ends of the keel sump. Ground out the grid laminate from the sump.

Added 1.5 oz mat, 24 oz woven roving (WR), mat, WR, then two layers of 8.6 oz unidirectional (uni) to the hull, including the sump. All were laminated with epoxy laminating resin. WR and uni were S-glass. Unis were run in the athwartships direction.

Built floors from 2x douglas fir.

laminated mat, WR, and Unis over the douglas fir floors, using approximately the same schedule as for the hull, above. Laminations extended across the entire area of the hull laminated above.

reinstalled the original structural grid over the new laminated grid. The old grid was tab-laminated onto the hull with mat, WR and epoxy. cut joints in the old grid were ground out and taper-laminated with mat, WR and polyester resin, since the old grid was polyester.

Furniture is now being put back in the boat.