Seghe - Munda boat

The short 15 minute flight from Seghe to Munda doesn't operate on Sat or Sun. Is there a boat transfer between the two, either way? How long and how much?

Thanks

Are you talking about a ferry or an outboard doing a scheduled transfer? You should be able to hire someone with an outboard to take you across though you will probably need to book it in advance.
Expect to pay (in Solomon dollars) at least $100 to hire the boat, and $100 for the driver and crew (usually at least 2), as well as $50 to $100 a gallon for petrol. (These may be more in the West - that is what I would expect to pay in less-commercialised Malaita).