I would assess the value on two aspects.
First, the physical realities:
- the boat is now a 28-year-old 13-footer. The hull has probably aged well, but the other major elements are the engine and the trailer.
- the 1998 Mercury 40-HP engine--if original--is very likely a two-stroke-power-cycle design using carburetors, and is either a two-cylinder or three cylinder design. Its value would not be more than $1,000. Also, the engine was probably rigged by the dealer on these boats, and was more often an OMC engine (Johnson or Evinrude).
- a 1998 trailer--if there is one included in the package--could easily need significant refurbishment, such as new tires, new bearings, a new winch strap, new running lamps. Unless recently completely refurbished, the trailer value would not be more than $1,000.
Assuming the boat was in really excellent condition, with the original wood finish intact and no sign of hull damage or repair, I would not expect the hull to be worth more than $10,000. So asking $12,000 might be an appropriate initial price.
Now the intangible aspect, which is principally that the boat was designated as a special anniversary model. How much is that worth? My feeling is the value of the anniversary model depends entirely on the buyer. Perhaps a very particular buyer will be attracted to having a specially-designated 13-foot hull that was marked as an anniversary model. If there were such a buyer, then there could be a premium price paid. This element might appeal to someone who was a very avid enthusiast and owner of multiple older Boston Whaler boats, and who would like to add a 13-footer to his collection. The essential difference is a collector might not actually use the boat very much in order to preserve its original condition.
On the other hand, a buyer who is looking for a 13-foot boat to be put to significant use every year, is unlikely to be attracted to the aspect that he is paying extra because the boat has this intangible quality as an anniversary model.
In the end, getting a truly premium price for the boat as an anniversary model depends a great deal on two elements:
- the boat has to be in precisely original condition and have very little signs of use, and
- the buyer must be attracted to the concept of owning a special or limited edition hull.
Also, without any detailed photographs of the boat that reveal its present condition, the value of the boat is difficult to estimate, particularly on the aspect of it being a limited edition.
And as in all cases, the asking price will determine how quickly a buyer will be found. The higher the price, the longer it will take to find a buyer.