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Old 02-22-2012, 05:31 AM   #21
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RE: Safety of Gas Engines

Old Stone wrote:
I have one of each. the 40' has big block Chryslers - 40 gls/hr.* plan to give it away on top of that.
********* Carl,* Give it to TonyB and be done with it.* Happy Spring!


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Old 02-22-2012, 05:31 AM   #22
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Safety of Gas Engines

rwidman wrote:psneeld wrote:
More old wives tale crap about methanol and worry about fire and an assistance tower I see a pretty good cross section of hundreds of boats each teay...many are out of the methanol conversion problems a year or so ago...just how many boat fires/explosions*are because of a NORMALLY maintained and operated gas engine each year?

get a grip stand a much bigger chance of dying on our hyways that from methanol or gas engines blowing you up.

Notice how I didn't discuss CO...that's a biggie....I would use at least 3 levels of safety alarms and other safety precaustions using a gas genset and sleeping aboard.

"Methanol" ?

*sorry was just reading alternative fuels article and it stuck..

-- Edited by psneeld on Wednesday 22nd of February 2012 07:35:45 AM

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Old 02-22-2012, 05:35 AM   #23
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RE: Safety of Gas Engines

rwidman wrote:
Gasoline power in a boat is inherently less safe than diesel power.

How do we know that? Because of the extra safety equipment that must be installed in a gasoline powered boat. The short list includes blowers to extract gasoline fumes, ignition protected starters, alternators, voltage regulators, and anything else electrical that is installed in the engine room or compartment such as inverters, battery chargers and heaters, and CO detectors in sleeping quarters.

Now if all that equipment is installed and in good working order, and the safety proceedures are followed as far as closing the boat up while fueling and running the blowers for four minutes before starting the engines, a well maintained gasoline powered boat should be as safe as a diesel powered boat without all this equipment and precautions.

As in my example above, lots of people will overlook some of these precautions because they haven't personally seen a boat explode. Will you really run the blower for four minutes before starting the genset so you can watch The Price Is Right on TV? Somehow, I doubt it.
*No I never run blowers on a gas boat...that's an insane waste of my valuable time...*

I crack a hatch to the bilge and less than 5 seconds I know the right answer.
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Old 02-22-2012, 06:20 AM   #24
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RE: Safety of Gas Engines

My experience with big block gas (383 Chryslers) in a large vessel says keeping to hull speed yields about 1 - 1.3*nmpg at 1700 - 1800*RPM. Modern gassers according to boat reviews posted in the various magazines shows a bit better* for a 20,000**lb Cruisers, Four Winns or*Searay.

As best I recall, the 44 Tollys ( an efficient and*great hull design) with gas get about .5 to .7 nmpg at 18 - 20 knots and .8 to .9*nmpg with 3208 Cats at same speed. These are the last*+40' vessels that offered gas or diesel on the same hull that I am aware of - you can find either today in the PNW*with about a $40 to*$60K price differential. Many gasser Tolly*44s have been converted to diesel. One of the better I have seen used a 330 HP*Cummins. Surprisingly, the Cummins being a 6 afforded a bit better ER layout than a V8 diesel or gas.

Buying a Tolly 44 gasser and planning for a diesel drop in at a later date may not be a bad idea, if you don't mind turning wrenches and being a carpenter. A gentleman on boat diesel reported at length on a 44 Trojan conversion, another good gas to diesel choice.
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Old 02-22-2012, 08:13 AM   #25
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Safety of Gas Engines

Important items regarding gas motors that*I neglected to mention on my other post, and, as may have been alluded to on other posts herein:
-********NEVER, NEVER, NEVER sleep inside boat with gasoline gen set or engines running when boat is not moving, no matter what alarms are on board or how secure you feel with the fuel system being tight (i.e. leak/fume free) or how much ventilation from outside you feel is occurring.* Also, with any gas motor running, always keep one or more CO alarms operational and keep some exterior airflow areas open into interior sections of boat when persons are inside or soon to go inside... being that you are anchored, docked or cruising at any speed.
-********Properly maintained (good lubricants with often-change intervals are the name of the game) and run correctly gasoline engines useful duration hours (before rebuild or replacement) will approach that of diesel.* Ive seen and had gas engines still running strong at 3000 hours.* Rule of thumb for gas engines: Averaged rpm at cruise should be no more than 60% of WOT; with gas engines, less averaged rpm generally = increased life span.* Gas engine power ratio to cubic inch displacement: Again less is more regarding increased lifespan, i.e. good ratio is approximately .7 hp to 1 cid.* Soon as gas engine gets into 1 to 1 hp to cid ratio engine lifespan will generally decrease.* Above 1 to 1 ratio, where hp is greater than cid, and a considerably lower lifespan usually occurs on gas engines.
-********Properly shopped and self installed portions/items/parts on gas motors can be extremely affordable and easy to accomplish*compared to diesel motors.* Gas engines rebuild or replacement is also relatively low cost.* 1/5<sup>th</sup> to 1/10<sup>th</sup> cost comparison to diesel*is not unusual.* And, gas engines in a well laid out ER (such as I show in picts of previous post) are pretty much a snap for keeping a good maintenance schedule or for changing parts when required.* Also, gas engine mechanics are plentiful and usually reasonably priced... when assistance is needed.
Cheers! - Art
PS: I use Soltron fuel additive and experience no stale gas problems.* As well, the*aluminum gas tanks*remain clean. Informative site:*

-- Edited by Art on Wednesday 22nd of February 2012 11:25:46 AM
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Old 02-22-2012, 08:27 AM   #26
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RE: Safety of Gas Engines

If you have a diesel, there's no question...diesel is best. There's something macho about a diesel that attracts us, and I don't dispute that as a valid reason to own one.

I've had both. The pervasive diesel smell turns me off, as does the mechanical (and now electrical) complexity. My carbed 350 gives me a sense of comfort and independence. I'll gladly live with the 'inherent dangers' for the peace of mind associated with easy and cheap do it yourself maintenance and parts.
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Old 02-22-2012, 11:39 AM   #27
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Safety of Gas Engines

Tony B wrote:

The other alternative is a motoryacht. Most motoryachts have gas engines. I feel safe on them when I know they*have been well maintained.
*How are you defining "motoryacht?"* To me, a motoryacht is a tri-cabin cruiser (trawler if you must but I don't use that term for our boats) with a full-width aft cabin.* Another term for it is "sundeck."* But Grand Banks calls them "motoryachts" so that's the image the term conjurs up in my mind when I hear it.

So to me, most motoryachts are diesel powered.

As to gas vs diesel, I think it's more to do with the type of boat than the type of engine.* For many years I fished on a gas powered boat in Hawaii (Uniflite sportfisherman, twin Chrysler V-8s and Vee-drives).* Never had any problems or concerns.

For a heavy, slow, economical cruiser like the kind we own now, diesels make a lot more sense.* Relatively low revving, lots of torque, very low fuel use.

Diesel engines because of their heavy construction will supposedly go longer between overhauls but how important that is will be dependent on how many hours you intend to put on the boat.* If you run it a lot and put hundreds or thousands of hours on a boat in a year, diesel probably makes more sense.* If you operate the boat the typical 100-150 hours a year, it will take some twenty or more years to put just 3,000 hours on the engines.* So the theoretically shorter life of a gas engine may not matter at all to you assuming it's suited to the boat and the type of boating you want to do.

Diesels have some safety advantages in that a weepy fuel line or leaking fuel filter won't fill the bilge with easily-ignited fumes.* So you can "get away" with more with a diesel engine.* A diesel engine has fewer systems, the primary advantage being there is no ignition system.* But diesels have their downsides.* They can be hard to start in cold weather.* Service and repairs are generally more expensive although the theory is you don't need to mess with a diesel as much as a gas engine.

So if you factor in all the advantages and disadvantages it's kind of six of one, half dozen of the other.* I would choose one over the other based on what is being powered and how I'm going to use it rather than make a boat-buying decsion solely on a bunch of theoretical safety issues.* A boat's propulsion system is going to be as safe or as dangerous as you make it by your own operation, service, and maintenance practices.

-- Edited by Marin on Wednesday 22nd of February 2012 01:43:28 PM

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