That's Free as in a Free Beer, i know what you're thinking, but this method is perfectly legal, from what i understand it's no more different from a library loaning out the physical book
For those who don't know, Titanic: The Ship Magnificent is one of the best technical manuals about the Titanic and olympic class in general, think of it like a haynes manual (ironically haynes also made a titanic manual, and while it's quite detailed, it's still nowhere near the level that is T:TSM) but it's expensive, both volumes are like £100 on amazon, this method you can read Vol. 1, which is about the technical and construction, for free, on the internet.
The Internet Archive is a non-profit digital library, in addition to T:TSM they have a lot of other good stuff.
Note: If the site refuses to connect or claims it has a security problem, check your ISPs parental controls, IA is blocked by default on many due to some of the content it hosts.
Free and as easy as making an account on any other service, if you're concerned about privacy or data breaches you can use a burner email address.
Once you've made a verified account you can log in and find Titanic: The Ship Magnificent, at the top of the page there will be a button to borrow, simply click it and you can read the book!
The IA explains how this system works but essentially you can borrow some digital books up to an hour or 14 days depending on the book, the 1 hour books, like T:TSM, renew automatically if you're actively reading it, there's no late fees, and i should imagine no one else can read the book while you "have" it, some more popular books have a waiting list.
The only downside is that you cannot download a copy of the book, only the 14 day ones allow an encrypted copy which needs to be read in a reader application linked to your IA account.