I bought an I-36 last year that was in need of some TLC. I'm doing it all myself. The Islander website is mediocre for specific questions and repairs. The website is brutal to navigate, and is primarily designed for the racing done in San Francisco. I'm located in Maine- So not much help for me-
I learned that there are some things to consider- What's your budget after all is completed to get the boat into the water? Just because you need an engine, are you willing to replace the 40 year old aluminum fuel tank since the engine is out? Stuff like this is worth considering, but adds to the end costs quickly!
I found my engine (Universal M25-XP) in OK shape after sitting 6 years. It has not run since I bought it, I am working on it now. I found it needed 3 injectors rebuilt ($150), and maybe a couple gaskets ($100). I may need the diesel injector pump worked on too ($300). But these engines are typically pretty tough. Unless you have been told there was water damage in the engine, or shards of metal are found in the oil... just how bad is the engine?
Don't forget about the Hurth transmission... That's another $2k if you replace it- Chances are, $1,000 in some basic maintenance and you can get a diesel to fire up and run pretty well for a while- They are more robust then you think- Don't forget that there are used/reconditioned engines everywhere (I found a U M25-XP at a yard in Quincy MA in EXCELLENT shape for $2k... just drop it in a boat and go) And any diesel mechanic makes more money on a rebuild/refit then just looking one over to tell you it's decent- Do your own homework and see what you can learn for the long-term and try and save $5k~$10k. Plus if you do the work yourself, you save huge money, and learn a lot of safety and mechanics when out at sea... you're the one who needs to solve problems when stuff breaks...
The boats themselves are pretty nice. 2 major issues my boat needs addressing-
1: I have learned for my boat, the decks delaminated do to water penetrating around deck fittings, mostly around the chain plates, and the water caused delaminating when the water froze over the winters, popping apart the bond of fiberglass to the plywood core. The plywood core was lightly rotted about 1"~3" around the chain plate holes for the plates, so I peeled away the inner fiberglass laminate from inside the cabin, leaving the upper glassed deck untouched, I let the wood core dry for a year (worked on other things while it dries...see below), and worked by using a hole saw to remove the bad areas (4"~5" saw). I then used CPES to inject from the deck above (lots of smaller holes drilled in the deck to let CPES seep down) to restrengthen the mostly good plywood, then epoxied in new circles, injected epoxy into the upper deck where it was delaminated, and I am in the process of putting the laminate back in place on the bottom (inside the cabin). I did not see the value in removing ALL the plywood, when it was 80% still good, just needed some reinforcement with CPES, which is AMAZING stuff by the way- A yard quoted me $10k ~ $20k for thes job, which included deck hardware removal, and doing the work on the top deck only. This price included new deck paint only where the work was completed. That's a lot of cash in my book!
2: Do to the age of the boat, and era the boat was made, the boat was assembled in 2 pieces, the hull and the deck. The deck is lowered onto the hull, then a bedding compound that is petroleum based was used to seal the joint where the deck and hull meet. Over 40 years of life, the petroleum dries out, leaving the deck/hull joint as porous as a sponge. Water would pour into the cabin when it rained at this joint all around the boat. I removed all the stanchions, removed the toe rails and then pried the deck/hull joint open by backing out screws (do not remove them fully), cleaning out the joint in 2~3' sections, then bedding this joint with 3M 5200, since this should never have to be removed or separated, this is a good use of 5200. Now, the deck/hull joint is water tight. Yes, this is a bit of work, but totally doable with simple hand tools, 2~3 weekend of work (if you have more hands, its much faster, I did all this solo). But I can't justify paying $6k for a yard to do this, when I can learn and know more about my boat, so when SHTF out at sea, I know more about my boat then the yard does-
By no means am I an expert, but I'm enjoying the work and love the boat. Check my little blogging site if you want- www islander36 net
Good luck with any purchase... just remember the 2 happiest days of owning your boat....