Gas verse Diesel Engines

[Comodave]

I used to test people in the CGA boat crew program. One of the things they had to do was put out a fire with a portable extinguisher. We went to a local fire department, the chief had a large basin with water in it and he poured some diesel on the water. Then he lit a match and stuck it in the diesel, it went out. He progressed up to finally a road flare and stuck it in the diesel and it still wouldn’t light. I asked him to put some gas in the basin. He said no, too dangerous. He finally relented and put a capful of gas in with the diesel. Then he threw a lit match at the basin, it went up with a big woosh. Ask me which is safer, gas or diesel…

 

[Hyperion]

You are fear mongering. If gas was dangerous insurance companies wouldn’t insure them. Next you are going to tell me anything less than a Nordhavn is to dangerous to go boating in.

That was not my intention. Please help me learn what information I posted was incorrect. I learn something new every day and welcome it.

I like Nordhavn but I like to go places they can't and don't understand how those owners find meaning in life without brightwork.

A good article on this subject
https://www.passagemaker.com/technical/vapor-and-spark-the-argument-for-marine-gasoline-engines

 

[Portage_Bay]

The boats I had in mind when I wrote that are IO and inboards. Engine and fuel system within the hull. Too many of them around here to count and very rare to hear of problems. I've got a lot of experience with and around gas powered boats. Including building them. You are correct that gas fumes are explosive. But when you follow the well established safety protocols, install and test the fume detectors and routinely inspect the fuel system then gas powered boats are safe.

This is because 99% of them use outboards and the big danger with gasoline is that the fumes are not flammable, they are explosive. In a large boat with inboards I could dump 50 gallons of diesel in my bilge and leave it for a month then light a match and nothing would happen. You do the same with 1 gallon of gas and leave it overnight and a small spark comes off your starter and the boat will explode into smithereens.

 

[Hyperion]

The boats I had in mind when I wrote that are IO and inboards. Engine and fuel system within the hull. Too many of them around here to count and very rare to hear of problems. I've got a lot of experience with and around gas powered boats. Including building them. You are correct that gas fumes are explosive. But when you follow the well established safety protocols, install and test the fume detectors and routinely inspect the fuel system then gas powered boats are safe.

I completely agree that a gasoline inboard can be safe if the correct precautions are taken. I race motorcycles, and we routinely take a very dangerous situation and mitigate it's risk with several steps and considerations. I do not want to imply that there are gas boats exploding every day in marinas around the world but for the question, "gas vs diesel" (and in this forum an inboard can be assumed) it would be wrong and irresponsible to not discuss the flashpoint and safety implications being so different.

 

[psneeld]

Often it's not what you say but how it is said.

I should know.... I am accused of it all the time......

With accidents.... without stating the root cause of the accident... pretty had to draw conclusions why one thing is safer than another. Like propane explosions or CO poisoning....gas often falls into the operator error category...

Not saying gas can't be dangerous...but drowning accounts for something like 80% of boating fatalities.... yet we all use boats and they are in the water.

 

[Hyperion]

I guess you are right. I probably should have put a bunch of emojis in it :lol::lol:. Text coms can come across a bit dry.

 

[Don L]

I my search for a maybe future 40-50o trawler I have been disregarding all boats with a gas engine.

Is this something to not be concerned about?

As the OP of this I wonder what the results would been if I had attached a poll

 

[Cold Duck]

Just a note, while cruising thru out central America for a few years there were a half dozen boat fires. Not one of them was caused by a gas engine or gasoline. They all were caused by cooking fuels. I prefer diesel but that's just the way I use the boat. If you are going to do a lot of dock sitting and cruising short distances for your boating, there's no reason not to consider gas. If you plan to coastal cruise fairly long distances, diesel will be the only way to go IMHO. We have a number of 40-50fters in our YC that are gas and they get around just fine. Gas engines are easier and cheaper to work on as an amateur engine repair man (I know I'll get some push back here). There is room for you to decide either way depending on how you plan to operate your vessel. Good luck.

 

[Turtle Blues]

My 2c is shop for the boat. Engines are a consideration when assessing overall condition.
I have flogged both without mercy in sport-fishing boats and have a real respect for the Crusaders.
Since the reformulation to low sulfur diesel the fuel cost differential between the 2 types has been substantially narrowed.

 

[Gdavid]

My concern with gasoline powered boats, particularly older inboard outboard or inboard setups, is that they require the operator to know what they are doing. You need to know what you are doing on anyboat, with regard to safe operation, but on a gasoline, inboard boat, the stakes are higher in this regard.

More often than not, I observe people that don't seem to know what they are doing on the water, from running aground, wandering aimlessly in a narrow channel, struggling to dock, etc. I struggle to trust that these struggling boaters are knowledgeable and diligent about maintaining a sound fuel system and running their blowers and checking for fumes. In my area, older, gasoline powered sterndrive powered boats are the cheapest to buy used and frequently end up in the hands of new boaters.

I own such a boat, a cheaply constructed 1996 bowrider with a 3.0 Liter, 4 cylinder Mercruiser. It has an aluminum tank which cannot be fully inspected. I check the bilge religiously and keep the bilge dry because the boat is stored on a trailer in a detached garage. There are many similar boats kept in salt water with partially filled bilges (potentially salt water) lapping at the bottom of those aluminum tanks. I am very cautious about mine, I just doubt that everyone is. On a larger gas boat, the engine compartments are larger, more room for fumes to accumulate and more blower time required to clear them (unless larger blowers have been installed) and there is also more room for non-ignition protected devices to be installed by ignorant owners. Yes, I'm weary of such boats, they have their place and just require special attention.

 

[Gdavid]

To further my comments above regarding lower budget boats ending up in the hands of ignorant owners, a Silverton 34' is an example of a such a boat. They tend to end up in the hands of inexperienced owners because they are a lot of boat for the money and are pretty common. They are not inherently bad boats but due to the low value of them, they tend to end up in the wrong hands. Neither of these cases are related to explosions, but being grossly and improperly overloaded:

https://www.soundingsonline.com/features/silverton-sinking-were-27-people-too-many-to-carry

https://gcaptain.com/san-francisco-capsize-echoes-past-tragedy-kandi-won-khaleesi/

I had one of these in the slip next to me last year, I haven't seen it this year. The owner was nice enough but a typical Silverton 34' owner, first boat and learning on the fly. I would love for the owner to return, with a different boat.