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This is a very common problem with *improperly blocked* Pearsons (especially the 26, 30, and the Flyer).
How to block a Pearson (or just about any boat with a 'swept back' keel).
1. Set a block of wood just aft and under the leading edge of the keel.
2. Look at where the trailing edge of the keel joins the hull .... draw an imaginary vertical line down to the bottom of the keel ---- the second block of wood under the keel goes IN FRONT OF this imaginary line. Any blocking under the keel aft of this imaginary line will cause hull deflection, especially in P30s, P26s, and Flyers. Any blocking under the aft end of the keel can cause the bottom aft end of the 'swept back' keel to break ... there is NO ballast in the bottom aft end of the keel, it's hollow and it cannot support much weight!
2A. "MOST" of the boat's weight should be onto the block just behind the keel's leading edge.
3. Set up 4 jackstands AT the bulkheads (there is no bulkhead on the aft port side of a P30 but set a Jackstand there anyway)
4. Add a vee poppit jackstand at the bow, another vee-poppit between the rudder and the prop ..... and set these vee poppits very TIGHT !!!!!
5. If the boat is stored with the mast up, dont relax the rigging.
What has happened is that improper blocking under the aft section (behind that imaginary line) is causing a 'moment-force' that is causing the keel to ROTATE (in the vertical plane) and is driving the aft edge of the keel INTO the hull ... and the hull is stress relieving itself through such 'deflections' (planar 'buckling').
Not to worry about what has already happened. In the entire history of when Pearson was actively in business there was never any delamination caused by improper keel blocking. The Pearson brothers at that time were the best in the business in fiberglass design. When the boat is returned to the water, such defections will pop-out over time. If the boat is accessible to a travel lift, re-set the boat to the above directions .... otherwise wait until spring .... but if you cant 'reblock' be sure to add those vee poppits and set them TIGHT, especially the one that goes between the rudder and the prop.
Remedy/Prevention - is to ALWAYS give your yard a drawing of where the blocking goes and where and how many the jackstands should be , and apply graphic indicaters along the waterline where the 'bulkheads' are located.
DO NOT 'jack out', 'lever' from behind the liner, fill or 'fair' nor 'otherwise repair' any such hull deflections, they will ultimately return to 'normal' shape when the boat is back in the water. Proper blocking of a swept back keel will prevent this in the future.
FWIW your 'dimpling' / hull deflection appears to be very minor in comparison to a very badly blocked Pearson !!!!!!!
Pearsons of this era (Gruman Industries ownership) were 'floppy hulls' .... if you are actively racing this boat then consider to add longitudinal stiffeners running parallel to and 18-20" offset/outboard from where the bilge 'turns' from the keel. Just a kerfed 1x1" covered with 'tabbing' will do ... and will greatly stiffen the hull and the boat will then be a 'little faster' especially in 'rough' water. If you elect to add such 'stiffeners', do so when the boat is free floating in the water and not set on 'jackstands'.
Last edited by RichH; 12-19-2011 at 11:58 AM.