Hi,
I'm afraid there is no real answer to this, see comments on the topic below **LINK**
The best thing you can do is to put it on an online auction site with a full description and see what interest it attracts. There may be some previous recorded sales which will give you some indication of the price to ask. Generally speaking, amateur constructed model boats do not fetch very high prices. The regular members of this Forum tend to construct model boats rather than buy or sell them.
Alternatively, if you have a model boat club near you, then you could contact them to see if they can help. There is a list of clubs here: **LINK**
Colin Bishop