We extend to you a cordial "WELCOME ABOARD !" Come on in, make yourself at home, we are a friendly group of enthusiasts, and we also appreciate the classic Chris Craft Roamer, Corsair, and Lancer boats too , as they are all on the same family tree and share much in common !
Paul, Chris and All:
I am glad to see you spending some time thinking about this one. I would rethink the diesel option, the hull extention, and going with a single engine. The boat was designed for a certain set of parameters and/or criteria. There is some leeway within this relm, BUT once you have pushed the margins too far, you are now in R&D and not restoration/rennovation and all bets are off. Better save the diesels for another boat and go with the V-6 rebuild. If you need a boat to put the diesels in, let me know. I have a couple of 31' Chris Craft's that would be great for those engines and I will make one of them available in a deal you can't refuse!
I have converted a boat from a gas to a diesel, but this was a case of a drop-in Kabota engine for an Atomic 4. Everything fit just like the original. I just changed out the fuel tank etc. What you are suggesting is something different.
Now for my concerns. With the 25, you may have some issues fitting the engines on the frames, you may have a fuel tank issue. This is a real task, as the tank lies between the two frames and under the deck. You may have to cut the deck to fit the engines, then you have to refit engine boxes. Weight is a big concern. Its not the mass, but where the mass gets distributed. The 25 does not have the bottom shape to make this an easy task and all the handling charactorists could go out the window, especially if you go with all three options of single engine, diesel, and hull extention. She simply will not sit the same way in the water. You will have a heat issue as the diesels run hotter and heat up the boat more than the gas engines, not to mention the noise and rattle. You will most likely end up changing a lot of guages on your panel to accommodate the diesels and that means restringing more wire, new gauges, and such. You will be completely modifying the boat by the time it is all over, I am afraid. Your resale ability will go out the window because you may be too far out.
With all these fears, I know you can handle the job none-the-less. But I think you will be much farther ahead fixing the one bad gas engine, keeping the boat original as possible and getting back on the water much faster. Good luck either way you go. We will be pulling for you.