Logo of a ship building company

Is this just for fun/practice or is it for a company? If it is for a company, you should know that shark fins are a pretty crowded space as far as logos go: https://www.google.com/search?q=shark+fin+logo&client=safari&rls=en&tbm=...

A few tips from David Airey's excellent book “Logo Design Love” which I think are important for you to keep in mind:

10. Work in black and white
No amount of fancy gradients or color choices will rescue a poorly designed mark.
By refraining from using color until the end of the process, you and your client are free from distractions of a preference for, say, green, which leaves you free to focus on the idea.

12. Remember legibility
The public most likely will glance at the logos you design for only a second or two before moving on. So legibility is key, especially when the brand isn’t well-known. For instance, a client’s handwriting may look pretty, but if most people can’t read it immediately, then don’t consider using it as a logotype.

17. Aid recognition
Keeping your design simple makes it easier for people
to recognize it the next time they see it. Consider large corporations like Mitsubishi, Samsung, FedEx, and BBC. Their logos are simple in appearance, and they’re easier to recognize because of it. Keeping it simple also allows for flexibility in size. Ideally, your logo will work at a minimum of around one inch without loss of detail.

18. Test at a variety of sizes
Try printing your work to ensure it’s clean, with a good level of contrast on paper, and not pixelated. But don’t just print a single logo. Replicate the design at a range of sizes and colors for variation. There’s no point in using a full page of paper for just one tiny design.

23. Don’t be afraid of mistakes
Everyone makes mistakes. Learn from them, and move on.