Man CR800 6 cyl sensors

What sensors is he looking for specifically? Having a schematic isn't going to help much as it won't show you where each sensor is located generally, just that it exists.

That's a square black cap that has the sender underneath behind the air filter. Usually about 4-6" from the air filter. The black cap with the wiring usually has a small phillips screw in the center holding it onto the sender. These senders can go bad if someone cleaned the air filter on the washable air filters and got overzealous with the air filter oil. Right now I'm managing 2 yachts with common rails. 1100's and the brand new 800's and I don't believe this is the same motor as your buddies as it's a brand new design, 2019 engine.

The set I'm managing has around 135 hours already and most of them at cruise. But I think I've added 2 quarts of oil to each engine in the 135 hours. We had a very minor raw water leak on both motors on the hard pipe aft joint on the hard pipe leaving the heat exchanger, both fixed under warranty. They run smooth, are quiet and powerful, no vibration. The only downside is if you have to pour oil into the engine you have to remove a plastic cover that goes over the entire top of the engine and that would take time and be a pain in the rear. Not really a fan of the big decorative covers on the top and sides of the engine. They look nice, but I'd rather see the engine itself easily for leaks and things of that nature. I've also run the new 1400's and those were a beast in the torque department.

Aren’t you going to need a little more hp on the next one

Two thumbs up

I like your trade-off analysis, although I think the SeaKeeper will go aft?

why aft?

Most of the yacht mananufacturers are now putting them closer to the stern, versus front of the engine room. They seem to have more of an effect closer to the stern I believe.

80% of our running with the 800 MAN's was at 80% load as we blazed all over the Bahamas. I did a lot of miles on each trip and added 1 quart per motor...….give or take...…..Our last trip we did 10 days (Fort Laud-Nassau-Cave Cay (exumas)- Staniel- Highbourne- Nassau), left the boat there for 5 days and did Nassau-Spanish Wells-Harbor Island-Highbourne-Shroud-Nassau-Ft. Laud each motor used 1 qt over the entire trip. They were 2/3 way up between add and full. Our previous trip was similar and all over the Abacos. But sadly, my tenure will end with them very shortly as the owner is trading it in on a new 66' MY with 1200 MAN's...….that will be here in 2 months.

Weight and center of gravity.

Not to get too technical, but the ideal set-up has the Longitudinal Center of Gravity (LCG) directly aligned with the Longitudinal Center of Buoyancy (LCB), then your boat sits level, no bow down or bow up trim at rest. These parameters, LCG and LCG can be measured as a percentage of the Waterline length forward of your transom. If you know your Waterline length, for a SF, a really rough estimate is 40% fwd of the transom is an approximation.

So for example, a Cabo 40 has an approximate Waterline of 35 feet. 40% of 35' is 14' measured from the centerline of the transom. This is the "tipping point" or fulcrum, picture something like a seesaw. Weight/mass forward of that point tends to drop the bow down, very undesirable in a Planing Craft. Weight/mass aft of that point results in a stern down situation, better for a Planing Craft which usually has aft fuel tanks. The further these weights are from this point, the bigger lever arm they have resulting in a bigger influence on trim.

You still have to balance the overall "equation" for your boat and not go to extremes.

I don't see manufacturers putting the seakeeper in the lazarette generally. I see most manufacturers them putting them at the aft of the engine room versus in front of the motors. Hatteras does put the seakeepers right in the stern lazarette on the 60' motor yacht, but the only one I can think of at the moment. Princess puts them in the generator room under the aft deck but forward of the stern crew quarters on their 62' motor yacht. Etc. fast SF tend to like the trim a little aft of the LCB, given the speed they cruise at, then a little trim tab brings the bow down to where you want it and creates stern lift at the same time.

It is important to know where your engine like to run it's oil level. Those sticks are not always accurate and the attitude of the engine when on plane contribute to different results for different boats. Mine will both run a the middle point if I add oil to "top" it off. It's back to the mid point by the time I'm back to the dock. Also important to take the readings under the same conditions each time.