I replaced the exhaust hose on our 1981 TRBS last year. The job is heinous but doable by one person in about 4-5 hours so long as you can crawl or bend into tight spaces and are not claustrophobic. I did not remove cabinetry or cut any new holes, but did take the door off the cabinet under the sink (see below).
Make sure it is not too hot and very important-do not crawl into a sail locker without ensuring the hasps can not close if the hatch closes on top of you-Sounds odd, but is a real danger if you are working alone (and a bit reminiscent of a tales from the crypt episode). I had reversed all the hatch clasps a while ago on my lockers to avoid any possibility of an accidental closure/lock should the seat/door slam down and was glad I had as I spent quite a bit of time in the sail locker inching hose into position and had the seat/door slam down over me several times. I would also suggest always keeping a cell phone handy in case you do get stuck as some positions can be a bit challenging.
In this endeavor, I used a hack saw to cut the old hose in 3 spots-in the transom well under the rear locker/lazarette (had to remove the hatch on the floor of the locker), in the large sail locker and in the main engine/muffler area. Mainly did this to make it easy to remove the hose in sections and to make it easier to work the hose off the transom exhaust fitting and off the muffler stem. Keep in mind, the hose is long and has pockets of skanky exhaust water that will drain at the most inopportune time-on you. Bring a bucket and have some old towels on hand. I suggest stuffing a rag in the ends of the hose as well as this will give some advanced notice of water about to drain.
Ultimately, it turned out to be easiest to work from the sail locker. I removed the old hose by working it through from the transom and from the cabin side after cutting the sections. Took a little effort but was not too hard.
Before removing, I tied a "finder line" to the old hose before pulling through so I could have some control of the new hose as I reversed the process. This was particularly important for the section going to the cabin.
Working in reverse, I took my new hose (courtesy of catalina direct) and tied the finder line to a hole I punched through the end and then began slowly feeding the hose through to the cabin, inch by painful inch. Note this requires climbing out of the locker, sticking your head into the cabinet under the sink and putting tension on the line, going back to the locker and feeding about 1-2 inches of hose (repeat about 40 times). There are 2 tough spots-one where the hose gets wedged between cabinet and hull and the other where a sharp turn into the cabinet under the sink occurs. These require a lot of working/nudging, etc. but are negotiable inch by inch.
The back end of the boat is a breeze in comparison and requires a similar process of applying tension on a feeder line while feeding in hose from the sail locker. There are no major bends/90 degree turns, so this is gratifyingly faster-though still requires some odd angles of position as you hang upside down in the lazarette pulling the hose toward and onto the transom fixture.
I ended up having to cut off about 2 feet of hose before placing on the transom exhaust fixture. A hack saw does this well and can be done after you have fed all the hose through (would NOT do this before you finish feeding hose through all aperatures as realizing your hose is too short at that stage will bring no joy).
If you have a willing accomplice, this can go much more quickly as one person tugs on the line while the other sits in the sail locker and feeds in hose inch by inch.
As above, it is a hideous and dirty job befitting Mike Rowe. However, once done, you will have an understanding of how the boat is set up that 99% of owners never have (though in truth most probably do not want).
Chris
