It’s great to see so much thought out into this. Sounds like you have a really good plan.
BTW, I was really surprised by the Gardner’s fuel efficiency. I have always believed that newer engines are more fuel efficient, not less so. Possible exceptions are for after treatment incineration which consumes fuel not benefiting power output. But if that consumption graph is accurate, it’s as much as 20% more fuel efficient. That’s just the opposite of what I would have expected.
And related, how do all the EU and US emissions requirements work with the old engine? For some reason I thought that a new boat with old grandfathered engine wasn’t acceptable. But it would seem that it is OK?
Thanks for the very kind vote of confidence Peter. Means a lot coming from someone as experienced as you.
Yes, these Gardner engines really are amazing aren't they! Hard to believe that in spite of their age, ours is now almost 50 years old and yet it is still one of the most thermally efficient production diesel engines every produced. I covered more on this in an early post you may have read where I talked in more detail about these Gardner engines which attain just a hair over 40% thermal efficiency. Paired with our Nogva CPP prop that will let us dial in our load to optimal conditions at any speed and in any conditions we expect to achieve some incredibly high overall efficiency and low fuel burn. Plus I'm an old gearhead from my days wrenching HD rigs, hot rodding cars and motorcycles and restoring antiques so to my eyes these Gardners are like mechanical works of art.
I understand how and why priorities changed over the past 100 years or so and HP became so much more important than torque and HP to weight ratios also became important, but I do think there has been a bit of loosing sight of the forest for the trees. HP has the factor of time which torque doesn't and so RPM's had to keep going up as the engine manufacturers chased after more and more HP, which they have done an amazing job of. But there are a lot of collateral consequences of this with lighter and lighter moving parts, smaller bores with shorter strokes such that modern engines are running with much higher overall "stress" and closer and closer to the limits of metallurgy and physics. These newer engines are still marvels of engineering to me as well with their performance and longevity. However for our application in our XPM boat, I think this very robust, slow revving, high torque engine coupled to the controllable pitch prop will give us far superior overall efficiency.
One of the more interesting things to me is the shift in the metrics for measuring "efficiency" and pollutants. I won't go into it here but my reference to the forest and the trees syndrome is in part related to how most of the pollutant measurements are in absolute PPM kinds of measurements and not in the overall outputs of an engine relative to a given task. Our Gardner will definately have higher PPM counts for things like NOx etc. but we will also burn far fewer liters on a passage than would a modern engine driving the same boat at the same speeds. I'm certainly no expert in this but my logic and math says that in this like to like comparison of boat and passage our Gardner 6LXP will produce less overall pollutants for a given passage than would a modern engine and that seems to me to be a truer kind of efficiency or at least one that I prefer to have.
Your understanding of requirements for old engines in new boats is quite correct for a production boat that will be registered in the USA and many other countries. In our case our boat will not be registered in the USA and so our overall boat will meet CE certification for everything but the engine. This suits us just fine as we intend to own and sail her for many decades to come. If/when we do end up selling, the rules as I understand them are than in most countries including the US, EU, etc., when selling a boat that is more than 5 years old the engine requirements do not apply and the "grandfathered" older engines are not a problem.
This is certainly not a route that most others would want to follow but that is how we are proceeding. Future XPM owners will be going for modern engines from the likes of JD, Scania, CAT, Cummins, etc. which will be great choices and serve them very well.
BTW, your recent posting going over how you made your engine decisions for the main and auxiliary engine in your new build was excellent (as usual) and I learned a lot from reading it several times. It still surprises me that there is such a big difference in radiated heat from these different engines you considered and I'm still a bit puzzled at this. For our boat and engine I've chosen to design an engine room that is dedicated entirely to just the engine and everything else lives outside of it in my "Workshop" area. I've focused on having this much smaller space be extremely well ventilated and be easily able to keep the ER air temps down to well below a Delta T of 25 which I think will work out very well for our mighty Gardner.
Looking forward to continuing to follow your new build and learning from you as I do Peter. Thanks for all your input here as well.
- Wayne