I think you should look at other newsletters from SailWorld etc.

None of them use PDF files because
(a) They're difficult to read on a smartphone or tablet
(b) They get blocked by firewalls as a security risk
(c) They can't be customised for the target audience
(d) You can't ensure that users get the email
(e) You can't easily track what people read or click on.
(f) Your server may be blacklisted for spamming as users click on the spam button instead of delete.

Also big block of text are unlikely to be read by time-poor people.

The solution is to use emails created using HTML and inline CSS as this will be properly rendered in the email client of the user (Outlook, Gmail, AOL etc). This newsletter should contain a short summary of each topic with a thumbnail picture and a link for the full editorial and larger pic.

Fortunately there are tools that make this a point and click process using templates and give you in-depth reports of what users click on as well. They also ensure your mails are delivered and keep the mailing process separate from your servers. They also automatically create an online archive version for those who want to read it in a browser and will push content to social media.

I'd suggest looking at Mailchimp (free for up to 2000 contacts), Constant Contact and Aweber depending on your list size.