Theses are my opinions, take them for what they are worth
1. chain plates, you can't inspect. They ALL need replacing unless already done, last 38 was made in 93? I think they were all made from 304 SS, newer plates will be made from 316, a little weaker metal, but more resistant to corrosion
and new one will be bigger to make up for strength loss, Mine are now 30 yrs old and will be replaced next year, turn key cost is $10,000, then they will outlast me as old ones lasted 30 yrs, new ones are better, and I doubt I have 30 yrs left, so chain plates are really a non issue, just know it takes 10 grand and you will never have to do anything to them again.
tank is good til it leaks
and there are quite a few that have been repaired and years later are still OK, but honestly I believe it's a crap shoot. I run all my water slowly through an activated charcoal filter to remove chlorine as I believe chlorine is what eats them, if you remove chlorine, they ought to last longer than we will, but if you get one that the PO kept his tanks
sterilized by adding chlorine, it may fail the day you buy it. I plan on having a water maker and using only water we make, that has no chlorine of course.
3, fuel tank
ought to last forever, IF you keep water out of it or off of it, as designed there should never get an water on it, or in it, fuel
does not corrode aluminum
, I don't believe. Course we are back to did the PO keep fuel clean?
4. waste tank is easy, Ronco gave me a quote of $150 dollars earlier this week, does not include shipping
of course, but tank is easily removed, half day job tops, new hoses make it a full day job though, and I think you would be crazy to go back with aluminum
, plastic Ronco tank, ought to outlast me, like new chainplates will
5. Rudder is a common make, I forget who, but it is readily available and subject to the same problems any other foam filled rudder is, that is coin tap test it, and push really hard on it when the boat is on the hard
to ensure noting inside is loose, you can drill a hole to see if there is water in it, mine is 30 yrs old and so far no problems.