Scotland Holiday

[Euphful]

I'm going on holiday with wife and 2 children to haven camp near Ayr.what is the cheapest way to go by boat from Belfast to scotland

[Buenchico]

Fares vary by season and time of day, so it's not really possible to provide accurate information unless we know when you're travelling, what type of vehicle you've got (if any!) and how many people there are.

However you' might save yourself some driving (and, of course, fuel costs) by using the ferry services from Larne, rather than from Belfast. The times are here:
http://www.poferries.com/tourist/content/pages/template/routes_cairnryan_troon_-_larne_Timetable_timetable_CRLA_TR.htm
(Departures in light type are best, as they go to/from Troon, which is only 11 miles from Ayr. Departures in bold type go to/from Cairnryan, which is 46 miles from Ayr).

Click the 'Book now' link, at the bottom left of that page to get a quote for your travel plans.

Use the booking panel, at the top right, here to get a quote for travel on the Belfast to Cairnryan service:
http://www.stenaline.co.uk/ferry/routes/cairnryan-belfast/

Chris