Bolt on keels are par for the course from that era of boat building for this style of boats. It continues to be the standard for production boats. The j40 has a good access to all the keel bolts. Do a visual inspection around them- are they corroded or pitted? Look at the area around them and the washers- is the FRP cracking, crazed, or otherwise deformed? Thats about all you can do as a lay person, in addition to looking at the keel-jump joint as others have suggested. It will be obvious if there is a problem when you see the boat from the outside. As far as I am aware, J boats havent had any issues with keels falling off as a limited amount of other builder's may have seen. Based on the fact that you asked the question, you need a surveyor. Your insurance company will likely require a surveyor anyway. Get a survey.
I would check the rudder and bearing- put your hands on the rudder when the boat is out of the water and wiggle it. If there is play around the shaft then the bearing is probably past its service life. Its a very common problem on these boats and those similar with a spade rudder. You can fix it yourself if you're reasonably handy. If not, a competent yard can handle that for you over the course of a winter. Ill let others speak to the cost/level of effort. It is not a show stopper, in my opinion. On that note- the rudder will likely survey wet due to water intrusion. As long as its not delaminated its probably fine for most sailing short of crossing an ocean. Again, my opinion. Our rudder surveyed wet but its solid and not delaminated so that moved down the list pretty far. I got a quote for a top of the line replacement from CCI last summer for a foam cored-carbon spade for around $5000 plus shipping to/from. They'd go a little less if you want to reuse the existing rudder stock. The rudder stock/post is fiberglass and the internals are either high grade stainl;ess or fiberglass so minimal risk of corrosion issues/failure. Get a survey.
The boats have balsa cored decks and hulls. THERE WILL BE WET SPOTS. Period. You're either very lucky or you've found a boat that has had some of the trouble areas addressed already. Wet core is a problem in ANY balsa cored boat- so most boats made in the late 1980s through 2000s. It is not a show stopper on its own, in my opinion. Again, any competent yard can address local areas of wet core. We had the portside deck in way of the chain plate and forward end of the genoa track re-cored this year in the Boston area for ~$5000, for reference. A surveyor can help you figure out how to proceed short term and beyond.
A few common J/boats troublespots to check with a moisture meter/ tapping hammer (if youre competent) or check with a surveyor. None of these are MAJOR on their own, but all of them together could get expense to fix. The best part of fiberglass boats is that basically everything can be fixed.
-Check the wooden main bulkhead around where the chainplates bolt. Look for corrosion on the chain plates/fasteners and evidence of water (discoloration) or rot (soft) in this bulkhead.
-Propeller strut area of the hull tends to be wet
-areas of the hull around thru hulls
-areas of hull, topsides, and deck around any kind of vent (gas tank, water tanks)
-cockpit sole around the wheel pedestal and where skipper stands
-deck area around chain plates and genoa tracks
-engine mounts wore
A good surveyor will run you around $25/ft depending where in the country you are and will be worth their weight in gold. If you're willing accept some defects then you have a good punchlist of projects with some expert advice on where to start. They will find things you didnt think of. Multiple people suggested we use Jeff Stone (
jstone....@gmail.com). He knows J/boats, he knows sailboats in this size range and era, and knew the J40 very well. We used him to survey hull #79 before we purchased and did not regret it.
We bought last spring so its all pretty fresh in my mind. I am happy to answer other questions if you email directly. We are thrilled with the boat, the quality, and performance.
Drew