Fine by me if it is unambiguous. 

Agreed, even if it's a little ambiguous. In some cases, the only thing the protestor knows is the sail number. The RC has the contact information. 
Presumably, the RC has made an effort to provide unique sail numbers on the water, too.  Not always successful....

Does the inclusion of a sail number in the description of incident meet the requirements of 60.3(a)?

Yes, it does, in my view. I probably see more forms like this than not. It's fine (Edit: I would confirm with the protestor that the boat mentioned in the incident description is the protestee. If not, then there's a 60.3(a) problem.).

To me, as long as the protestee is able to look at the form and know that they are the ones being protested, then I think the requirement is met.  If the form says "the red hulled boat" and there is only one red hulled boat in the fleet, that may be sufficient.

Rule 60.3(a) Delivering a Protest requires that "When delivered, a protest shall be in writing and identify the protestor, the protestee, and the incident."
As described the hearing request seems to conform with the rule.  

I have no disagreement with the above responses.
However, it could lead to an invalid hearing being commenced if the incorrect sail number was put in the incident description.
I suppose this is the same as the wrong sail number being provided in the respondent's box and when this is established the hearing request should then be declared invalid.
The electronic system used at my club will not allow a protest to be submitted unless there is an entry in the respective fields of Initiator, respondent and incident description so people are prompted to ensure all necessary info is provided.

 The electronic system used at my club will not allow a protest to be submitted unless there is an entry in the respective fields of Initiator, respondent and incident description so people are prompted to ensure all necessary info is provided.

This of course would be user-friendly. Unfortunately being user-friendly does not seem to be on the agenda of many of those who write the systems we are obliged to use.
Each system seems to be good at one aspect of event management and poor at others. As a result, a major multi-class event I am attending is intending to use M2S for entries, Halsail for results and RRS for the protest committee!

A supplementary question:
A competitor delivers a protest identifying the boat as, for instance 'the sailor from XXX (country) who always wears a pink life jacket. After the protest time limit, the competitor discovers the correct sail number. Rule 60.3 does not allow for information to be corrected or updated. 
What should the competitor do?
If the competitor delivers a second protest with the protestee's sail number, should the PC extend the time limit.

Gordon re: "Rule 60.3 does not allow for information to be corrected or updated. "

Though the new Part 5 doesn't specifically state that protest information can be updated, it doesn't say that it can't either. 

I think information can be updated with more specificity as long as the min at filing is submitted.  They could submit a drawing after the PTL for instance if the min's are met. 

So in your example, as long as there is only one pink PFD out there and then later they supply the sail #, that seems  fine to me.  I think the PC should determine at the beginning of the hearing during validity if in fact the sailor wore a pink PFD. 

My concern with saying the pink lifejacket from a country is sufficient is in properly posting the hearing to notify the protester if the sail # is not found before the required posting time. It shouldn’t be the RC or jury’s responsibility to ID the protestee.

So what if they give you a sail # that is not even registered in the event? (They indicated they were unsure of the number prior to giving us the form.) Do you go ahead and tell them so they understand that it’ll be invalid if they file it? We did.  

The form is just a handy way to organize the 60.3 a) requirements. You could hand in a protest written on a cocktail napkin in lipstick, and so long as it meets 60.3 a) it's valid.

I'm still waiting for a protest to be filed this way. I have strange things on my judge's bingo card. :)

Never seen lipstick, but I’ve seen a cocktail napkin! 🤩

Re: cocktail napkin ... someone must have a pic of the famous NYC-YC protest on the cocktail napkin with the absolute minimum info on it .. that was deemed (under the rules at the time) to be valid. 

Please post if you do. 

Alas, I saw the napkin I saw decades before we all had cameras in our pockets whenever we had clothes on, but it met the requirements for validity (and still would), and was good for a laugh (and I’m pretty sure the protestor was making a point).

I think the test as to whether the boat is properly identified or not is;
Is the PC or jury sec. able to identify the boat? 
If the form and hearing advice was displayed on the noticeboard and the protestee is listed as 'the guy with the pink shirt and orange hat' and no one turns up at the hearing and I would not know where to find them I would have some difficulty is saying the protestor had properly advised who the protestee was.

There you go Ang!

It's a key part of my judge training materials.  Always generates a good conversation.

 Angelo wrote:
Though the new Part 5 doesn't specifically state that protest information can be updated, it doesn't say that it can't either.   
RRS 60.3 clearly states: WHEN DELIVERED... 
When is a protest delivered? I would argue that it is delivered when it is handed over to the race office, or entered by the protestor into the electronic system.

I see no provision for changing in any way the required information after the protest has been delivered.

Gordon,
I agree. However, there is nothing to prevent a protestor from submitting a further protest with the necessary information if it is within the time limit.
I would not consider it good reason to extend the time limit if the revised protest came in too late.