live aboard boat

Yes

I do like that comment..

1100 hrs on gas engines is quite a bit.
Time for the top end to be re-built at around 12 to 1500 hrs ?

If both engines were properly maintained & the gas engine closed system cooled; The gas engine is over 1/2 it life, the diesel engine is about 1/4 life.
Comparing gas and diesels below 400 HP and operated with in their duty cycles, the cost of ownership is cheaper for the diesel than the gas.

The SeeSaw point is how often you operate, the extra up front price you paid for the diesels & what discount you can get from your insurance company.

IMO, a sitting gas engine deteriorates faster also.

You are on a forum specifically for "Talkin' Big Boats that Belch Black Smoke!", so there might be some bias toward diesel over gas engines. I worked in the marina industry, been an automotive engineer for 30 years and a gearhead for much longer. I've worked on a study Toyota did comparing ownership cost of gas vs. diesel for different size vehicles, so I'm familiar with what and how to compare. I ran the numbers and for my use, gas engines will be far cheaper for me with this size boat and the hours I'll put on it and type of use. My next boat might be diesel, if I go bigger or want do a lot more cruising, fishing, commercial dredging, towing barges,...

In salt water, full closed-loop cooling will be important for a gas engine to last. If the exhaust manifolds are cooled by sea water, they will need to be replaced every three years or so, adding some to ownership cost, but not a lot.

I'll just post these again for reference, these guys might know a bit:

http://www.boats.com/resources/boat-engines-choosing-gas-or-diesel/#.WiW3sExuJRQ

http://www.yachtsurvey.com/GasDiesel.htm

And they might not. I personally give very little credence to Pascoe and what few articles once did make sense are now 20 years old. I agree with you that there are applications for which gas engines are very appropriate choices and the person posting here may be one of those. However, the comments to which Chesapeake and Crapps responded weren't just any gas boat.

Here is what he presented:

1100hrs crusader, is priced cheaper and need a bottom job and generator governor repaired. seems to me the owner no longer want to care for it.
​

vs.

looks to be well maintained. it has 1300 hrs diesel but this could mean higher annual maintenance cost.
​

We're talking a poorly maintained, high usage, gas engine vs. a well maintained, low usage, diesel engine. Yes, 1100 hours gas is high usage and 1300 hours diesel is low.

And to answer the maintenance cost, the annual maintenance on the gas engine is more than the diesel. Not prohibitively more but it becomes a big issue when you're talking about a poorly maintained gas engine with high hours.

The boats.com article supports the warnings others have given.

Gasoline-fueled engines are typically going to run 1,500 hours before major work is needed.​

That puts the 1100 hour engine at 70%+ of it's normal time before major work and that's on a well maintained engine.

I think for many looking for a lower dollar entry point, gas is the right choice. Just probably not the gas boat he's talking about.

I have read many times Pascoe's site. It is good reading but I don't agree with everything.
But the fundamentals of theories for thought are there to get those brain cells thinking in a better direction.

I never read that other site before. Maybe a more updated site but I don't agree with everything there either.

My comment on post#84 was meant to respond to paluga's comment. OB expanded on my thoughts with his much more graceful typing and public skills.

I did conclude on post #84 it's a SeeSaw that has to be considered when purchasing. 30West seems to be happy with his gas choice.

I've been in bilges most of my life. Still learning, still disagreeing with some things.
I am still biased that where gas engines and diesel engines can compare, after the up front cost; the diesels are cheaper to maintain in a long run.
They usually hold more value also to help retrieve that larger up front cost.

Ralph (Crapps). You're also on the coast. Very different to be in Holland, Michigan and Southern Georgia. Both are different than where Paulga is located but his is either coastal or closer to the coast. For lake boating as in Michigan, the majority of the boats are gas. I boated on a lake until 5 years ago where diesel isn't even sold on the lake. Most boaters don't put a lot of hours per year on their engines. Lake boaters tend to do even fewer average hours, especially those in a northern climate with only seasonal boating.

Oh, and we maintained our engines very well. When I traded our 24' Cobalt, it was 6 years old and had 2500 hours on the engines with no rebuild. When we sold our 30' Cobalt, it was 6 years old and had 2300 hours, no rebuild. However, that is not normal, neither the usage or the life before major work. We did do the annual service 3 times a year and the 3 year service every year plus the 5 year service every two years. Our annual maintenance costs were quite high but then so was our usage.

A lot has changed in gas and diesel engines in the past 20 years, I'll agree with that. Ten years ago it was rare to see a truck with a GM bigblock reach 200k without a rebuild, now it is expected, and those are the gas engines going into boats.

At the same time, smaller, lighter, higher-output recreational marine diesels have become the norm in a huge segment of pleasure boats. Those are not the heavy, sloppy, smelly diesels that ran forever in fishing boats and ferries and yachts since the argument of steam vs internal combustion. These low-emission, high-output engines rely on tight tolerances and minimal mass to meet government and consumer demands. And they are often too small to push large planing hulls they are put in, at planing speed. I've read on countless boat forums that all diesel engines are made to run at full-throttle indefinitely, and that is what a lot of owners do. Dealers are actually telling buyers this is true. And I found a lot of young diesel boats with replaced or very tired engines, as a result. The for-sale ads hopefully point out the huge amounts of money spent on the diesel engines, making me doubtful this has been an inexpensive adventure.

I've read a lot of things on forums that aren't true and certainly all diesel engines are not made to run at full throttle indefinitely. I also know very few owners treating them that way. You may see many diesel engines being replaced in your area but on the coast we don't seen very many recent models replaced. Those being replaced are very old and have been through a lot.

A lot is the marinizer too in the quality of engines, not just who built the block. One thing that has kept quality gas engines has been the proliferation of ski and wake boats. This is so tied together that Correct Craft bought several engine builders including Crusader, which is mentioned in this thread.

Gas are still junk and expensive to maintain compared to diesels. A little better off in fresh water, and with a short season like Michigan they can make sense for a low hour boater. First off gasoline is about $1 per gallon more on the water. Then you have SOOOOOO many components to change. Manifolds/risers (every 5 years), plugs, wires, cap, rotor, cooling systems, in addition to the oil and filters, fuel filters etc. But there are also soooooo many additional items to go bad over a diesel and create a stoppage.

I'm glad to read I'm not the only one here old enough to remember when engines had distributors. And even mechanical distributors with points. Feels like I'm on a ride in Mr. Peabody's WABAC Machine.

Don't think I've ever heard/read that before, anywhere.

-Chris

It is certainly untrue to run any recreational marine diesel or E rated engine full throttle indefinitely that you will see in 98% of yachts. They are recommended to run at 80% load indefinitely. Commercial rated engines are designed to be run full throttle indefinitely if you want, but they are a lower HP rating (or detuned) than their recreational brothers.

I searched long and hard for a twin diesel around 40' and under, mostly online, but also flew to Texas, Canada, Florida, and walked a lot of docks in the Great Lakes. I avoided fishing boats and trawler-style, just looked at recreational boats capable of good speed. I'm pretty sure this is a segment of boat buyers that knows the least about boats and their proper care and maintenance, and will believe a lot of BS.

I wanted to know as much as possible about each boat model I looked at, and searched the internet for data, reviews, discussion, and posts from current and past owners. In the forums on these specific boats, there are discussions where owners insist their diesel engines are rated for continuous full power. Some say 80%, as Capt J says above, these numbers are tossed around on forums.

I could blame the owners, but the industry seems to intentionally mislead. Cummins call their cheapest, lowest rated recreational engines "High Output", and they are rated for "infrequent use in variable load applications with a load factor of 10-30 percent." Not full-power or 80% power, and not enough continuous power to plane most planing hull boats they end up in. But, professional reviewers and dealers told buyers these boats could cruise on a plane. They can, but the engines won't last, and I found a fair amount with tired engines or replaced engines. Reviewers and dealers are apparently relying on their expertise based on older engines, and probably not being given the engine rating specs for these new engines.

This is a new development in diesel engines, these recreational diesel engines have been lightened and cheapened and tightened up, and souped-up, to reduce emissions, meet a demand, and make money. These engines aren't in 20-year old yachts or bigger yachts that I know of, they are in low-end, large express cruisers and small bridge cruisers, built in the past 15 years, and there are a lot of those out there. It is a fairly specific niche, serious yacht people probably don't get deep into.

These aren't terrible engines, but owner/operators of boats with these engines need to understand how they need to be operated and maintained, or they end up with very expensive problems. The OP of this thread wants to own a diesel boat in this niche, I think he should be cautious.

"Cummins call their cheapest, lowest rated recreational engines "High Output", and they are rated for "infrequent use in variable load applications with a load factor of 10-30 percent."
I'm close to throwing in da meter..
What model and examples do you have on this??

The High Output engines are not rated for infrequent use with variable load applications with a load factor of 10-30 percent. They're designed to be rated to cruise at 80% load. However, I take care of a 2006 yacht with QSM 11's and right on the data plate it says useful life: 10 years/1000 hours. Perhaps that's for emissions purposes or something, who knows.....

The 80% load comment does not nullify the infrequent 10-30% load factor rating, it just muddies the definition.