It would be a very rare case for a failed damper plate to damage anything else. It would have to be quite explosive and perhaps have large chunks lodged between the block and flywheel. Typically the springs break and tear up the drive plate without damaging anything else. When it completely fails it will not spin the trans input shaft with any load on it, so bring a paddle or two. If it's not terribly noisy yet and you're just trying to get out a few more times this season I'd run it as is and do the job when you're done for the season. not sure what boat we're talking about but if it's a DD it should be an easy job under a day of work so long as you have a setup to lift the engine. If it's a vdrive, well... Have fun with that because it'll be tight and take twice as long.
Also think about any "while I've got the engine out" things to do. At the least clean your bilge well under the engine. If motor mounts or engine are starting to rust clean and paint them, check oil pan condition (rust, thin, etc.), consider an oil drain hose instead of plug if you don't already have one or if you have one inspect condition and replace if in doubt, check rear main seal for any sign of leakage, check trans input shaft seal for signs of leakage, if engine is high hours (1000+) you may want to pull the pan and inspect bearings, etc... This is all cheap and easy while you have the engine out but either not worth doing or very labor intensive if just pulling it for one of these things alone.
Last edited by cadunkle; 09-18-2013 at 8:27 AM.