Gas vs. Diesel

[TDunn]

There are two fuel docks locally that sell gas and one of them sells ethanol free gas. That is the only source of ethanol free gas I know of other than buying avgas at the airport. Based on an on-line search, our local fuel dock is one of two fuel docks in the state that sells ethanol free gas. The other place is on an inland lake.

 

[sbu22]

Wow! I had no idea. That would be very tough to deal with. As hygroscopic as the ethanol blends are, that's a real problem. There are a fair number of mogas stations pumping non-ethanol as well.

 

[Codger2]

Walt are you saying you have a strong opinion in #176?

You can assume that....

 

[BandB]

One thing you see, and I'll bet if we surveyed our views vs. background this would be confirmed, those of us who have had gas engines much of our lives are comfortable with them while those who have always, or a great majority of the time, only had diesels, are not comfortable with them. Makes sense.

 

[markpierce]

The two previous boats (auxiliary sailboats) I regularly used, one was inboard and one was outboard, both gasoline-powered. Ran the exhaust fan on the inboard before use. Experienced no problems with either.

Current boat was only available in diesel. I'm satisfied with the engine.

Don't try to convince me a "trawler" boat must be diesel powered. Nevertheless, I'm pleased my boat is diesel-powered.

 

[Art]

I know that there are many on this forum who have gassers & it is not my intention to debate their choice but in an attempt to clearly explain my position on gas engines, I offer the following.....

Walt - - >Your Big Meanie regarding gas doesn’t scare me.

I am however VERY conscious of safety measures and often applied looking/maintenance procedures. Liquid Gasoline does not burn... Gas Fumes/Vapors in ample airborne quantity and/or in an enclosed space do burn upon ample heat-ignition and can become explosive if containment area is saturated/enclosed when an ignition spark occurs.

Following is a quote that places gas dangers / explosion capabilities in their proper light. Cared for items and correct procedures aboard boat render liquid gasoline harmless. Gas engines and diesel engines aboard boat are just like everything else in the “pleasure” marine world – i.e. a tradeoff and a compromise. Both power units are very OK when placed into and correctly utilized in their service points designated.

“The truth is that liquid gasoline does not burn; only gasoline vapor can burn. That doesn't mean you can't set a bucket of gasoline on fire, it just means that what's actually burning is the vapor layer over the liquid where it mixes with the air.

Chemically, burning is literally the process of combining with oxygen. If there's no oxygen in the mix, there's no fire.

Gasoline vapor is not actually explosive, it just burns pretty quickly. It's comparably volatile to say, rubbing alcohol. That doesn't mean it's not quite dangerous. Any combustion processes that occurs under pressure (as in, in a closed container) will cause an explosion.

However, a Molotov cocktail is basically a fire bomb—it does not literally blow up like a stick of dynamite would. It's more like, say, an oil lamp; when it breaks, the flames from the rag (usually) spread to the other surfaces covered by the gas. More to the point, the rag itself is not inserted into the neck of the bottle: the bottle is in fact sealed closed, and the rag is just there to provide a source of open flame once the bottle breaks.

Wildly inaccurate Hollywood portrayal of explosions...

Fact: It is basically impossible to set a puddle of gasoline on fire by dropping a lit cigarette into it. It just puts the cigarette out.”


My Input: Throw the lit cigarette into an engine compartment aboard boat that has gas vapors at a critical level... Makes BIG BOOOOOM!!

 

[bayview]

Ski:

I always enjoyed listening to those old inline carbed engines light up a few cylinders at a time.

 

[Codger2]

Walt - - >Your Big Meanie regarding gas doesn’t scare me. !

It wasn't meant to scare you, Art! As I stated, it's my own opinion and is not meant to disparage those who have gasoline fueled boats. I live quite close to mission Bay in San Diego and have often seen the fire boats trying to put out a gasoline fueled boat fire. After seeing a few of those, one forms an opinion as to what kind of fuel they want their boat to run on. Also, my stint in the US Navy convinced me that one of the biggest dangers aboard a ship is fire and I try to do everything I can to mitigate that happening to me.

 

[Nomad Willy]

I remember that Walt. Fire fighting w fog nozzles ect. Fire indeed was serious business in the Navy.

That part of "gas v/s diesel" is obvious. But a reminder now and then is good. We lost a Willard reciently due to fire. Was underway in Puget Sound going to the Willard Rondy ...... Caught fire and just burned up.

 

[BandB]

I remember that Walt. Fire fighting w fog nozzles ect. Fire indeed was serious business in the Navy.
.

Wifey B: All I did was fight fire (yes, we did have to fight fires set in the training facility) in a course and I can tell you that is not fun. It's some tough business. It sure gave me some perspective and knowledge though. Boat fires can get out of hand so fast too and get to other boats if you don't make the right moves quickly. Best thing is to avoid them.

Comfort Levels-Propane the way many handle it scares me to death. Well, not literally. (Don't you just love the Heineken commercials with Neil Patrick Harris. Super cool). Now if I was gonna carry propane on a boat, the thing I'd do is have a really good fire protected place to store it. Gas. Well, tanks not built in scare me. Poorly watched engine rooms. But well cared for and well watched, I can be ok. Then it's like everywhere, the leading causes of house fires and of boat fires. The kitchen/galley with stuff left on unwatched. Smoking. Electrical wiring. Everytime you are tempted to hire some bozo who isn't licensed but says he's been doing it for 200 years just realize your and your guests' lives are at stake.

More on the electrical topic. We just almost but didn't stop at Fort Pierce City Marina. The new docks all have FGI to 2011 standards. Lots of the boats that come in have problems and have to be sent to the old docks that don't meet the standards. Test your boat or have someone test for electrical leaks and problems. Typically the gas fires are a combo deal with electrical weaknesses.

 

[rardoin]

I have had the pleasure to work on a few of those old flathead six marine engines. Chryslers. Raw water cooled, engine turned around backwards with flywheel on the front. Tranny mechanical and shared engine oil sump. Based on car engine blocks around 250cid. The marinization was pretty well done. And engines seemed to last reasonably long even with raw water cooling. A few are still alive, but most of these had most of their lives in fresh water. The salt water ones are long gone.

Those engines did require a little tweaking of the carb to run right, but once dialed in that was a very sweet running engine!!! Nothing seems as smooootttthhh as a straight six. And you can idle them down to like 400rpm and not stall. And quiet. About 100-150hp.

Those were the go-to engines from the 40's into the 60's, then replaced by the overhead valve v8's. Diesels did not really show up in numbers until the early 70's oil shock. Lehman was a pioneer then.

We had an old aluminum 26ft Lafitte skiff shrimp trawler (Hey...an actual bonafide trawler...well don't that take all) with one of the marinized chrysler sixes. It was rock solid dependable but had either a prop imbalance or bent shaft because when running on plane to getting to or from the grounds it would vibrate that aluminum hull and tickle my molars! An old oilfield driller told me that they used that engine as the power unit on several portable workover rigs in his day. He said you could hardly kill them and if it doesn't run, change your fuel filter, clean or change your points and your back in business.

 

[sbu22]

Codger2 states that he has "often seen the fire boats trying to put out a gasoline fueled boat fire."

I've been living on, driving, sailing, fixing, and eyeballing boats for fifty or so adult years. I can recall 4 or 5 boat fires that I have witnessed - of all sorts. Maybe I don't get out enough.

The Coasties' 2014 Recreational Boating Statistics list about 12,000,000 boats 65' and under as the US population. This shows 52 "Fire/explosion (fuel)" incidents. Of the 52, 10 are "Cabin motorboat" (I assume that's us) related, with 32 "Open motorboats" and the rest pontoons, PWs, etc. So that's less than one Cabin motorboat incident a month throughout the nation. One occurrance is too many, but I don't think those numbers qualify as "often".

I have seen (too many times) injuries and a few fatalities in refineries, petrochem plants, and tank farms where "it's only diesel" bit back hard.
Stipulated: Diesel has a much higher flashpoint (120-130 F) than gasoline (-35 to -45 F). However, whether it's a steel storage tank baking in the Texas sun or an operating engine room on a 90 degree day with 85 degree seawater injection temp, it's not hard to imagine meeting the diesel FP temp.

Both fuels demand serious attention to procedure, maintenance, and operation to maintain a safe operational state. Gas demands extra effort.

The OP asked an honest question. I think he deserves better than a gas to diesel propulsion comparison couched in terms of sudden screaming death vs puppies and ice cream.

 

[cool beans]

I was a firebug growing up, and can attest to how boring gas is. It's not like in the movies. You need a lot of oxygen and compression for an explosion to occur. If you put gas in a dryer, despite the effort required to light it off, the best you get is a split second "FWOOP". . .maybe a flash of flame, and the door pops open Doesn't even last long enough to blacken anything. . .

I'm less worried about errant fumes than actual spilled gas. Gas as an excellerant is fantastic! A sniff test and 30 second visual check before starting and a quick check before shoving off is my routine. But I would do that either gas or diesel, it's being prudent

BTW, only fire I know of in the 5 years of being in little creek, was an electrical fire. Guy's space heater shorted out, burned up a Formosa

 

[BruceK]

....The OP asked an honest question. I think he deserves better than a gas to diesel propulsion comparison couched in terms of sudden screaming death vs puppies and ice cream.

I don`t know, in the boat explosion case I was involved in years ago, if the baby blown into the air screamed before dying. The two adults I acted for had horrible injuries, all 4 limbs fractured,weeping infection sites from fragments forced deep into tissue by the explosion, etc. I`d like to forget it, I can`t, I don`t think it is wrong to raise safety as a consideration, as I did previously, without the grisly information above.
Something I learnt (if memory serves) from the investigations is the required ratio for combustion is 95% air 5% gas. A boat can be "safe" if the ratio is richer, but if air is added to the bilge by moving, that ratio can change. The problem lies in containment provided by hull and decks.
Despite my experience, I twice chartered gas boats from good companies, one was Halvorsen, and would nervously poke my nose into the ER. When I bought, I excluded gas engine boats from my search, including on safety grounds.

 

[Art]

I remember that Walt. Fire fighting w fog nozzles ect. Fire indeed was serious business in the Navy.

That part of "gas v/s diesel" is obvious. But a reminder now and then is good. We lost a Willard reciently due to fire. Was underway in Puget Sound going to the Willard Rondy ...... Caught fire and just burned up.

Eric... you didn't mention... gas or diesel?

 

[Codger2]

BTW, only fire I know of in the 5 years of being in little creek, was an electrical fire. Guy's space heater shorted out, burned up a Formosa

https://www.google.com/search?q=boat+fires+in+2015&ie=utf-8&oe=utf-

 

[LarryM]

Eric... you didn't mention... gas or diesel?

Liberty Call was a late Willard 30/4 which would have been powered by a Perkins or Yanmar diesel or similar. Every Willard I have ever heard of was diesel powered, and I've never heard of any that were repowered with gas.

Here is a link to a video of the fire.

And here are a couple of pics. The owner was able to escape aboard another boat and was not injured, but they were not able to rescue his dog. I never heard anything more about the cause of the fire.

 

[Marin]

There are a bunch of ways to burn a boat down. Gasoline is one. So is propane. So is a grease fire in the galley. So is an electrical short. So is smoking in bed.

I fished for years on a twin-engine, gasoline powered Uniflite in Hawaii. Engines worked great, always started, never started a fire. Two of our three boats are diesel. The diesels work great, always start, haven't started a fire. The gas engines (outboards) work great, almost always start )), and haven't started a fire. We have a propane galley on our PNW boat. Works great, hasn't started a fire or blown the boat up. We've never had a grease fire in the galley.

We almost had an electrical fire that could have burned down our PNW cabin cruiser. My wife smelled it and we caught it just in time.

Neither of us smoke.

Just about anything can be dangerous if you don't pay attention. There are reasons we would most likely not buy a heavy cruising boat powered by gasoline engines but fire risk isn't one of them. I believe that if a machine is designed and built properly and it's maintained and operated correctly, gasoline is every bit as safe as diesel.

Now in the hands of a careless boater, or a boater who isn't much for maintenance, or a boater who doesn't bother with common sense safety procedures and practices, a gasoline boat will be less forgiving than a diesel boat.

But my wife and I aren't any of those kinds of boaters, so for us it's six of one, half dozen of the other with regards to gas or diesel as far as safety is concerned.

 

[FF]

The US Navy and USCG require FR, Fire retardant resin , for their boats , and charter boats that carry over a minimum number of pax.

Oak planking has a burn rate of 100.

Std GRP resin a rate of 500

FR is required to have a rate of 100 or below.

Giving up 2 or 3% of laminate strength the burn rate can be down to 15.

However fine it is to have self extinguishing resin , the burning Fumes are deadly.

Once lit a std GRP hull is not easy to put out.

The cost difference of FR resin is a couple of cents a pound, but your boat assembler does not value your life that highly. And folks never demand it.

 

[Art]

The US Navy and USCG require FR, Fire retardant resin , for their boats , and charter boats that carry over a minimum number of pax.

Oak planking has a burn rate of 100.

Std GRP resin a rate of 500

FR is required to have a rate of 100 or below.

Giving up 2 or 3% of laminate strength the burn rate can be down to 15.

However fine it is to have self extinguishing resin , the burning Fumes are deadly.

Once lit a std GRP hull is not easy to put out.

The cost difference of FR resin is a couple of cents a pound, but your boat assembler does not value your life that highly. And folks never demand it.

FR resin... demanded by the govt, for thousands of their Viet Nam Delta patrol boats, is what caused all the blisters in Uniflite pleasure boats once in 1974 Uni switched all its boats to the same FP resin. That broke the company via class action suite. I imagine that today's high-tech FP resin mixture circumvents that blister problem???

 

[Baker]

I don`t know, in the boat explosion case I was involved in years ago, if the baby blown into the air screamed before dying. The two adults I acted for had horrible injuries, all 4 limbs fractured,weeping infection sites from fragments forced deep into tissue by the explosion, etc. I`d like to forget it, I can`t, I don`t think it is wrong to raise safety as a consideration, as I did previously, without the grisly information above.
Something I learnt (if memory serves) from the investigations is the required ratio for combustion is 95% air 5% gas. A boat can be "safe" if the ratio is richer, but if air is added to the bilge by moving, that ratio can change. The problem lies in containment provided by hull and decks.
Despite my experience, I twice chartered gas boats from good companies, one was Halvorsen, and would nervously poke my nose into the ER. When I bought, I excluded gas engine boats from my search, including on safety grounds.

I am with you Bruce. It has personally affected me. I have seen an explosion where there was nothing left of the boat except what was raining out of the sky. Hollywood could not have done a better job. Amazingly, no one died but all were critically injured and lost limbs and had 3rd degree burns. We even went through the fund raining process afterwards and did benefits to help piece those people back together with prosthetics. If my boat went faster than 7 knots I would have been first on the scene. I was about 400 yards away when it happened. THe only upside and likely the reason no one died was the coordination of the TowBoatUS and the USCG. He had those people loaded into his boat and the life flight helicopters were waiting when he got to a good drop off point.

Another somewhat recent incident in our marina was a boat with a bilge full of gasoline and a not very smart guy who decided to use a shop vac to clean it up. Boom....and he did die. It would be easy to shrug that one off as Darwinism but who knows what was going on. The dude died and many boats burned. Still a tragedy.

Gasoline boats are less safe than diesel boats. That is the reality of it. Can the risks be mitigated...sure. But not completely. You will pay more insurance for a gas boat for the reasons stated above. They burn and they kill(CO poisoning) more than diesel boats do.

 

[FF]

I imagine that today's high-tech FP resin mixture circumvents that blister problem???

After 40 years , of course the new FR does not have the problem Hetron did for 4-5 years , 40 years ago.

 

[Codger2]

Gasoline boats are less safe than diesel boats. That is the reality of it. Can the risks be mitigated...sure. But not completely. You will pay more insurance for a gas boat for the reasons stated above. They burn and they kill(CO poisoning) more than diesel boats do.

I tried in my post to actually say what Baker just wrote but I didn't have the guts. Thanks, John!

 

[Ski in NC]

One of the most chilling things I heard was a radio conversation involving a gasoline cruiser offshore of Jacksonville Fla. I was in my ride heading up the coast offshore. A man was running the boat from the flybridge and came down into the cabin to find his family unconscious. I don't remember all the details, but I think with ventilation they came to. For an hour I slowed down and just listened. I was too far to be any help.

I also participated in a CO fatality investigation as an engineer. Gasoline genset, poor ventilation and just the exact necessary weather conditions necessary combined. Kept walking by the bunk with vomit still on it.

 

[FF]

Any boat with an engine with the exhaust in the stern cam fill the vessel in the right aft wind conditions with exhaust.

North Sea exhaust (both sides vent) or a dry stack are probably safer.

 

[sunchaser]

Seen and heard of many boat related gas fires and exhaust deaths. They are so numerous that anyone considering a gas powered older vessel should pay strong heed. Older diesel vessels are inherently safer for three reasons, first diesel is much less combustible, second diesel evaporative vapors are low in comparison and third diesels pull in much more air resulting in a less toxic and diluted exhaust.

An interesting gas explosion I am aware of happened 30 years ago in a a marina on the Mississippi above St Louis. A fellow was routinely taking his secretary to his houseboat during lunch. His wife caught wind of what was going on and went to the houseboat one lunch hour and observed the action from a distance. Incensed, she returned the next day with hubbies rifle and fired two shots into the gas powered vessel. One punctured a fuel tank.

The wife left and the tank leaked, finally triggering the bilge pump to come on. BOOM

Both participants were lifted by the explosion into the water nude as the boat blew apart. responders included not only others in the marina but police, fire and the St Louis Post Dispatch. Lots of mirth, few injuries and a jailed wife. This is a happy story in comparison to Bruce's and many others.

I would never own an older gas tanked vessel. With the witches brew of alcohol fuels mandated, hoses, tanks, and fittings are real world leak points. Not to mention older FRP tanks potential incompatibility with E15.

Ten years ago each fuel fill line on my 9 year old SeaRay began weeping. Problem was a result of hose not able to withstand the Lake Powell high heat. Shame on SeaRay for using low grade hose.

So for the OP, why even pursue an old gas powered vessel unless you are planning on bringing each and every tank, line and fitting up to E15 compatibility - at great expense and still fraught with worry.

 

[Nomad Willy]

If this was a forum where 99% of members had gas boats the text would read very differently I think.

Electricity in your house is probably more dangerous than gas in your boat.

But a gas boat carries the very real danger always. And stuff happens.

 

[FF]

"They are so numerous that anyone considering a gas powered older vessel should pay strong heed."

If this were true , the folks with the most to loose every INSURANCE CARRIER would have noticed sometime in the last 50 -75 years and adjusted the policy rates.

Some fears are simply personal problems , and not real world demons.

 

[sunchaser]

If this were true , the folks with the most to loose every INSURANCE CARRIER would have noticed sometime in the last 50 -75 years and adjusted the policy rates

Right you are FF. Insurance carriers have higher deductibles for gas vs diesel and increase rates based upon age of vessel.

 

[AusCan]

Without a doubt, gasoline is more dangerous than diesel, but the risks can be mitigated.

With a well designed and maintained boat, I'd say the difference in risk between gasoline & diesel power is very minimal.
If the boat is very poorly designed and maintained, a gasoline inboard could be a nightmare.

ABYC regs and require blowers, bilge pumps, etc to be designed in a manner so it will not ignite gasoline vapour.
Here's an example: https://law.resource.org/pub/us/cfr/ibr/001/abyc.H-22.1986.pdf

They are designed that way, but if not properly installed or maintained, they may not stay that way.

Moral of the story - if gasoline powered, take extra good care of your boat.