Thats an easy job. Used to do them all the time.
No need to haul. an adjustable spanner would be perfect if you have one that will fit, which is unlikely.
Pipe wrench on the lock nut and main nut. Wire brush the threads clean so the lock nut can run back. Plenty of wd40 or similar on thread.
Take the time to set the wrenches properly, thats the key.
Break the lock between the the lock nut and the main nut. Run the back nut back.
Put the pipe wrenck on the body of the stuffing box and undo the main nut.
The important thing is not to turn the main body of the stuffing box in the tube connecting to the fibreglass.
Remove the main nut, slide it up towards the engine. Yea water coming in the boat. relax, it's not going to sink your boat if you have a working bilge pump
, and even if you did'nt it would take hours and hours.
Take your newly purchased pig tail and screw it aft between the shaft and the main body, Idea is to snag the old packing. Pull the packing out. Do this till all packing out. Clean inside as best as possible with whatever tool works best, likely a screwdriver.
Take pre prepared new packing liberaly lubed with your newly purchased packing lube. Instal in with cuts staggered.
Pre preppare packing by wrapping it around your shaft and marking then cutting. Will likely need 4.
Push new packing aft. lube plenty. push next packing aft. Etc.
Water flow will reduce at this point.
Screw on main nut. run back nut up to it.
It will need adjustment after running in all likeyhood. Perfect is a drip when engine running but zero or almost zero when not running.
Grease the entire thread area, locknut and main nut so that next time this is an easy job.
If someone tells you you have to haul to do this job .....well I will hold my honest opinion and just say they not of what they speak.
Remember, water running into the boat is not a cause to panic, big breath and realize that it really isnt as much as it seems.
I have posted this for the OP only, dont care to argue with the experts, I have only done this at least 50 times ranging from 3/4 shafts to 2 inch.