New sailor - What are the parts at the base of the mast?

I am a new sailor who completed ASA 101 ~1 month ago. I bought an old cheap 2000 Hobie Cat 17 (HIN: CCMLZ941K900). I do not know what I am doing. Here is a picture of ol' crusty:



This boat did not come with a boom, but it did come with a sail. The sail looks to be an old Whirlwind H17 SuperR Main (https://www.whirlwindsails.com/store/p7 ... _Main.html). The sail has a clew plate with 3 holes on it, at one end of the foot. The other end of the foot has 1 hole for the tack. Due to this, I believe this boat should have a boom and is an SE model, but I am not sure how else to confirm. I will need to figure out how to get a boom...

It does have a mast! Looking at the base of the mast, I am trying to identify what the parts are for. My questions for this forum post are in the below picture, and also pasted below it:



1. What are the metal things with the cam cleats on them, near the base of the mast?

2. What is the metal thing where a pin would go through, at the base of the mast? Is this where a boom would attach?

3. What is the big ovular metal thing for?

From reviewing the manual, for question #2, I do believe that is where the boom attaches. H17 Manual (see page ):

https://media.hobie.com/digital_assets/H17Manual.pdf

I have a 2000 H17Sport i bought in 2002. It appears you have a standard H17.
The difference is the sport has front spreader bar with a jib and boomlet.
The standard has no spreader bar, no jib and a full boom. So you are missing the boom.
I also have the Whirlwind Super R square top sail (actually 2) love them.
To see my boat go to 'Places to Sail' on this forum, The Gap, near the top post

Bottom of the mast has a connection for the boom and 6:1 downhaul (cam cleats). The horizontal pin is a keeper to lock the mast onto the pivit ball on the boat while raising the mast. You remove it once the mast is up.