You take a great shot but there is something in the image that you dont want. You could try and crop around the object or preferably you would use a content aware fill function to remove it.

Of course you can use Photoshop to manipulate the image, but it is expensive and likely overkill for the needs of most users. On the Mac there are a number of cheaper alternatives that provide the same functionality.

As a test I have used the same image (randomly sourced from Flickr) and run it through Inpaint - $4.99, Snapheal - $9.99 & Pixelmator - $29.99. I removed a seagull, the number 4 from the boat registration and the rope.

Source

For the purposes of the experiment I just painted over the objects at the normal size using the basic settings of the functions, better results may be achievable if you were to zoom in, change brush sizes etc.

Overall the results were pretty good. Inpaint had the best result – especially with the removal of the rope, followed by Snapheal and Pixelmator. I have found no app is consistently the best as the results differ depending on the image used and the objects removed.

Inpaint is limited in its functionality, Snapheal has basic editing  features while Pixelmator is a full image editing package. Pixelmator would be the choice if limited to choosing only 1 app but given their low prices you could buy them all and still have plenty of $ in your pocket compared to buying Photoshop.