I've seen too many first-time buyers make the same expensive mistakes. Here are 5 things that would've saved me thousands:

1. The purchase price is just the beginning.

Mooring, insurance, maintenance, fuel, registration — budget at least 10-15% of the boat's value per year in running costs. Most people don't.

2. Never skip the marine survey.

A $500-800 survey can save you from a $15,000 engine rebuild. If the seller pushes back on a survey, that's your answer.

3. Fibreglass doesn't mean maintenance-free.

Osmosis, gelcoat crazing, stringer rot — fibreglass boats have their own set of problems. Don't fall for "it's fibreglass, she'll be right."

4. Test in bad conditions, not good ones.

Anyone can sell you a boat on a calm sunny day. If you can, do your sea trial when it's a bit choppy. That's when you learn what the hull is really like.

5. Check the trailer as hard as you check the boat.

Bearings, brakes, winch, rollers, rust. A dodgy trailer will cost you $2-5K to replace and nobody thinks to inspect it properly.

I put together a full guide covering everything a first-time buyer needs to know — from what to look for at the first inspection through to negotiating and closing the deal.