Diesel Vs Gas Engines

[mikeling]

With all the good things I hear about diesel engines, why are most Cruisers build with Gas engines ?

[Cheechako]

$. If you mean power cruisers, the V8 engine base for those is very inexpensive compared with a diesel. A 250-300 HP diesel is very expensive. A GM V8 is very inexpensive. For instance, you can get a rebuilt long block for a GM based cruiser for about $1700

[a64pilot]

Purchase price of a gas powered boat is WAY less than a Diesel, but once bought, it flips.
It's way more expensive to operate a gas boat, vast majority of the smaller go fast "cruisers" rarely go very far, usually just to the closest sand bar / beach where people can party.
Finding them with very low hours isn't uncommon at all, after the first couple of 100 to 200 gl weekends, boat tends to sit a lot.

People that actually use their boat a lot as well, a boat like fish heavily or actually travel, usually won't consider a gas boat.
But if the mission is to have a place to go to at the beach and it will rarely leave the Marina, a gas boat can be a very good deal.

[Lepke]

Most small cruisers are built with gas engines because the finished boat has to fit in a market profitable for the builder. Also, high speed, high hp diesels are very expensive.
Large sport fishers, ocean sailors and boats about 40' and up is where you find diesels.

[valhalla360]

There is also power to weight ratios. Especially historically, a diesel would weigh a lot more to make the same power. This makes it harder to get on plane.

Around 40' gas engines start maxing out on HP, so they transition to diesel. (technically you an produce reliable gas engines of higher HP but pleasure boats don't drive the engine market)

[markpierce]

I've no urge to plane (as in bouncing upon waves.) I'd rather just plow through them.

[ranger58sb]

Originally Posted by mikeling

With all the good things I hear about diesel engines, why are most Cruisers build with Gas engines ?

Your premise would benefit from some modification. The market for power cruisers is larger in the 35-38'-and-below range mostly due to cost and need (want) factors. Gasoline engines are sufficient for most of the power cruisers in that size range. And then gas engines are also less expensive, for initial acquisition cost.

Diesels are generally required for larger/heavier power cruisers (or fishboats, whatever) but then that whole market is more $$$ in the first place. But most power cruisers in this range have diesels.

Diesels can be thought of as more efficient, but it takes a personal analysis of planned usage to decide whether diesel or gas is appropriate for a given application. Extreme examples might be "dock queen of any size" can be gas, "heavy sportfish with daily trips to the canyons" should be diesel... and then there's a full gamut of options in between those. In between, in the cross-over range, there's also a personal decision required about whether you want more efficiency at higher up-front cost (diesel), or would prefer to pay as you go (gas).

-Chris

[rwidman]

Originally Posted by mikeling

With all the good things I hear about diesel engines, why are most Cruisers build with Gas engines ?

I don't believe that is actually the case. My boat has a diesel engine. It's a small trawler but I suppose it is also a "cruiser".

[Sailmonkey]

Originally Posted by rwidman

I don't believe that is actually the case. My boat has a diesel engine. It's a small trawler but I suppose it is also a "cruiser".

Key word here being most, and I'll speculate "cruisers" means express type boats with small cabins.

Your boat, in the grand scheme of small powered vessels is an anomaly.


Sent from my iPhone using Cruisers Sailing Forum

[exMaggieDrum]

"Most" cruisers in the PNW have diesel engines, not gas. There are those "Express" power boats that have V-8's sometimes. Gas engines are higher maintenance and more dangerous than diesels. Both can be safe but you have to be way more careful with gas in enclosed spaces. Diesels are heavier and more expensive to buy. There are many small sailboats that have gas outboards but they are not your traditional "cruisers" as in long distance off shore cruising.

[tkeithlu]

Are you talking about planning, plowing, or staying within hull speed? At a bit less than 8 knots, my 60,000 pound trawler gets two miles to the gallon and diesel is the obvious choice. If you want to do 25 knots in a sport fisherman without planning you're going to need huge power per weight and gasoline is a necessary choice. Just about anything that actually planes uses gasoline for the weight saving and lower initial cost. I love diesel. Eight weeks from the Florida panhandle to the Bahamas and back used less than 1,000 gallons, and my engine room is safe, even when I once left a return valve closed, popped a hose and spilled fifty gallons into the bilge. At the other extreme, I once got to deal with the results of two commercial fishermen adding gasoline without turning off their engine/alternator. Bad scene. So... low speed long range go diesel. High speed and weight consideration, it's gasoline, but be damned careful with gasoline inboards.

[markpierce]

Most recreational boats use gasoline engines (cheap and expendable). Nevertheless, I've a low-horsepower diesel engine powering a 14-ton boat, which won't exceed hull speed. Happy with the results.

[tkeithlu]

Amen. My 1,100 pound 1960s 140 HP 4-53 Detroit Diesel is smooth as silk, and gets me close to hull speed at 2200 RPM. It moves 30 tons at 7.5 knots for less than four gallons per hour or two nautical miles per gallon.

[ranger58sb]

Originally Posted by tkeithlu

Just about anything that actually planes uses gasoline for the weight saving and lower initial cost.

Not exactly. Planing boats less than about 38' or maybe 40' (or maybe some of the older 43s or 45s) might use gas, but above that planing boats are mostly diesel. And there are lot of boats over 40' that plane, using diesel engines.

-Chris

[a64pilot]

You get much over 35' on a Sportfisherman, and there simply aren't big enough gas motors to make it work. Much over 40' with gas motors and you have a trawler whether it looks like one or not.
We have a 36' with twin 454's, and they were just barely enough motor, had to run them much harder than I liked to stay on plane