The 19th century British prime minister Disraeli said: Youth is for exuberance, adulthood for hard work and old age for regrets.
My advice would be to put together a business plan for your income, your labour and expenditure and most importantly, how you are going to get that income. How you are going to get that income is down to researching the market. See if there are any boat trade associations and ex-pat websites, in Hawaii, where you can ask appropriate questions. Always be very conservative on income and timescales to get the business established as it is very easy to be unrealistic here. Expect it to take at least 12months to establish the business, so you can start to make money in the 2nd year. If you can reach the point and confidence where you can say "I know know what I need to do to make this work" you are in with a fighting chance of making a successful business.
You know the old army saying: "the plan goes out of the window with the first shot, but your training doesn't". It is the same with a business plan, if it is well researched and you've made some good contacts, this is equivalent of your training, so you know what to do or who to ask to know what to do when things go wrong.
The is a global shortage of good IT security specialists, so an alternative lower risk plan might be to see if you can get a job in Hawaii to use this knowledge and at the same time pursue your boat building business. The key as I'm sure you know for working in the IT business is up-to-date knowledge, if you tried hard with the boat business for a couple of years, but had to give up it would be much more difficult to get back into the IT industry, where as if it took a year of two to get the boat business up and running part time, so it was a going concern, you could then leave the IT job.
Finally, you need to look at your personal circumstances and make sure your business will fit in with these not only in financial terms, but also personally as it is very easy to end up working very long hours, when you start a business, talk this through with your wife, so you have her full backing on your plans, as your wife's support especially when things are tough in business makes a massive difference.
I wish you every success with what ever you decide. I started my first business exactly 30 years ago this year and have no regrets, where I've worked for myself ever since. Life is an adventure and this has been a great adventure, some bits exceptionally good and some not so good, but I wouldn't of missed it for anything.