A CV should be no more than two pages of A4. Employers will make a decision on your CV in around 8 seconds, so if your CV is too long then they will loose interest and may overlook your application. Keep it short, and to the point. You can always expand on your CV once you are through to the interview.
If your CV shows clear gaps where there is no obvious sign of employment employers will be suspicious. Being unemployed for long periods of time would ring alarm bells with any yacht or company. But turn that time into a positive by detailing your achievements during that time. Were you studying or completing a course, learning a new skill or language? If you were then talk about it.
The superyacht industry can be fickle, yachts can be sold and you can be made redundant at a moments notice. The best way to prepare for every eventuality is to always keep your CV up to date. Whether you're looking for a job or not. Every time something significant occurs in your career, record it so you don't later forget something that could be important.
Gramatical errors, bad formatting, sloppy or inappropriate language... There is no excuse for any of these mistakes in a 2 page document about your achievements. This is your showcase, don't let it let you down. If you're unsure then use a spellchecker and ask someone else to double-check what you've written.
The superyacht industry is a small one, references and statements can easily be checked and if you have made up sections of your CV, then it will probably come to light.
Make sure your layout is easy to read, don't over clutter it or use strange icons. Keep it clean and simple and easy to read.