Hey Eugene..I posted another question just a little while ago about my centerboard possibly missing, and if it was safe to sail without it..do you have any input on this?
What makes you think it is missing? Have you attempted to crank it down? When I sail around I never really use it, so unless you are doing a pretty serious passage or facing some big blue I would not worry about it. I sail with it cranked up most of the time.
An Irwin 28 is a really great boat and I am proud to own one. I have had many sailors, many of whom are captains over much larger vessels shake my hand and tell me an Irwin 28 is a true classic and beautiful little sailboat. I know an older sailor who lived on one for almost 10 years and says it was the best years of his life. Be proud of what you have!
At 3.5 draft with it cranked up you can take on exactly what the boat was made for. Moderate conditions coastal cruising. An Irwin 28 has a better comfort ratio then ODay and Catalina. It also has a lower capsize ratio, so it is a nicer ride and safer in rough waters then most in it's class. There were only 3000 ever produced and there are not many still sailing today. So feel good knowing you have a classic.
I'd get the centerboard checked out by a yacht club mechanic so you know exactly what is going on with it. You can honestly just look at the centerboard cable running from aft (the cockpit) under the cabin floor to a block under the pull-up panels up by the head (bathroom) door. If the line feels like it is pretty tight, chances are it is there. If it is loose I'd question it. Make sure it is not over cranked too! It should not be ridiculously tight. You can use the crank handle in the cockpit and try to crank it back and forth to test. I know mine needs to be checked out also and cleaned / re-painted.
Also be sure the big stuffing box under the larger floor panel in the cabin is safe and not dripping. That big (usually rubber tubing) pipe under the larger pull-up floor panel is the sea cock for the centerboard cable.
You can sail her fine without the 7.5 draft the cranked down keel makes, but again, if you are looking to sail her down to the Caribbean or somewhere on big water, make sure she is sea worthy.