I inspected a used boat today and the boat has potential to consider making an offer, but I'm trying to determine if a mismatch in the gelcoat indicates a major repair was done on the hull.
If you look carefully at the exterior, there is a large area on the port side between the bootstripe and the gunwale, directly below the two large windows, where the gelcoat doesn't match the rest of the hull.
First I would look at the the rest of the hull. Are there similar variations in colour anywhere else. This discrepancy in shading can be the result of inconsistent cleaning. i.e.: parts of the boat were scrubbed with soap and parts weren't - (yes soap and no soap CAN look that different). If it is only that area then something has been done to the boat. When you look along the side of the hull - squint and try to sight longitudinally - is the surface smooth or are there a lot of irregularities and bumps ?
When I looked behind the port settee, in this area, the fiberglass is quite irregular, and isn't painted like most of the rest of the interior of the hull. Am I correct to assume there was a major hull repair in this area?
It doesn't look like it. The depth of the mat does not appear irregular and it is hard, if not impossible to marry the patch with the exisiting layup without creating a noticeable seam. In a properly constructed boat, the roving strips will terminate at different places in the hull in order to avoid weak spots.
Look on the starboard side and see if it is painted behind the furniture, or in areas that are not visible. Ask for permission to scrape a little bit of the paint off of the painted area and look at the colour of the glass and mat. Does it appear to be the same colour as the materials in the area that concerns you ?
The small wood blocks glassed to the hull support the settee seatback.
Do they look newer than the rest of the boat ?
I requested a copy of the most recent survey, which I was told was from 2004. What do you think? If there was a major hull repair, I'm pretty reluctant to go forward with an offer.
several more full resolution photos are posted at the link below: there is one photo in this set showing "cracked" blue/grey paint inside the hull that is present almost everywhere else the hull is visible from the interior.
more higher res photos
Looking at what you have provided I think that there has been a superficial repair to the boat - exterior gelcoat or paint. Is the hull still gelcoated or has it been painted. If painted - it is possible that the paint lifted in that area due either to improper application or due to improper storage and a retouch was done. If it is still gelcoat, then there may have been a case of the "pox" on that side or an unfortunate occurrence with a jetty. Ask for the 2004 survey and see if any mention is made of the area.
Ask the owner. If you like the boat a lot, and if there are no other units in your area in comparable condition then it is worth getting a survey done.
NOTE: If the boat was involved in a collision or some other traumatic incident, it is expensive to have the density and integrity of the hull sounded, but it can be done. There is a hand-held meter shaped like a brick that will read the varying densitiies of the hull, but even that is not 100% accurate.
IN order to purchase the boat with confidence I think that the owner should be able to provide you with a reasonable explanation for the discolouration, and any surface irregularities that may be present. This should be followed up with your own survey (imperative on any boat purchase). Personally, I would not buy the boat, as there are too many good boats out there for sale, and I would suggest you not even consider it if you are planning on venturing offshore at all, regardless of how infrequent those forays might be.