Structural grid repair for sailing yachts after grounding damage, including failed grid-to-hull bonding, delaminated tabbing and damage around keel-load areas.
Structural GRP
When the internal grid separates from the hull, the original load path has been interrupted.
The internal grid or floor structure distributes loads from the keel and other highly loaded areas into the hull. A severe grounding can break or delaminate the secondary bonding that ties this structure to the hull, even when the outside of the vessel does not show the full extent of the internal damage.
Typical signs of grid or bonding damage
- Cracking along grid-to-hull tabbing
- Visible separation or lifting at structural interfaces
- Delamination around floors, grid members or keel-load areas
- Damage or movement around the keel-bolt region
- Previous repairs or laminate that no longer has a sound bond to the hull
Repair method
A structural repair starts by exposing the actual damaged interface. Failed tabbing and unsound laminate are removed, and the remaining hull and grid surfaces are prepared so new laminate can bond to sound material. Reinforcement is then applied with fibre orientation chosen to transfer loads between the structure and hull rather than simply adding thickness.
Biaxial reinforcement and epoxy
Material choice depends on the yacht and the original construction. In the documented 50 ft grounding repair carried out by Quinten Maritime Solutions, the failed original chopped-strand-mat tabbing was replaced with biaxial fiberglass laid in the required orientation. The repair used epoxy instead of the original polyester resin. In that specific structure this created a substantially stronger grid-to-hull connection than simply recreating the failed original tabbing.
Real project: 50 ft sailing yacht
After a severe grounding, the yacht’s grid had delaminated from the hull. The failed connection was removed, rebuilt and finished throughout the affected bilge structure. The vessel returned from an effective total-loss condition to regular offshore service and continues to make North Sea passages.
Frequently asked questions
Can grid delamination be repaired without replacing the entire grid?
Sometimes. The repair scope depends on how much of the grid, hull laminate and original bonding remain sound. Local or sectional rebuilding may be possible where the surrounding structure is suitable for a proper structural bond.
Why does fibre orientation matter?
Reinforcement is most effective when the fibres are arranged to carry the loads expected through the joint. Structural tabbing is therefore designed around load transfer rather than simply applying random fibre in every direction.
Why remove the old tabbing instead of laminating over it?
New laminate is only useful when it is bonded into sound material. Failed or delaminated tabbing cannot provide a reliable structural foundation, so compromised material needs to be removed or taken back sufficiently before rebuilding.
Will the bilge look unfinished after a structural repair?
Not necessarily. After the structural work is complete, the repaired area can be faired and finished. In the documented project, gelcoat was applied over the repaired structure in the original bilge colour.
Grid damage after a grounding?
Structural assessment and composite repair on location.
Provide photographs of the bilge, grid, keel-bolt areas and any external keel damage where available.