SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Gas Vs. Deisel (are we crazy?)

20K views 31 replies 18 participants last post by  SailNet Archive 
#1 ·
Hello All. Looking for some experienced judgement here, with an open mind based on experience. My wife and I are moving to SW Florida in September for a new life and work. We currently live in Pittsburgh. BRRRRRR!! Way too cold. We want sailing to be a big part of our new life. We first wanted a boat at least 30'' w'' deisel, and all the accomadations we could acquire. Work and finances are dictating that we may have to scale back our dream boat to more smaller, say 25'', maybe trailerable. Our intended cruising grounds are the Keys, Tortugas, and the Bahamas or beyond (providing we can follow a flotilla across the Gulf Stream, we''re not crazy). We are seeing alot of boats for sale that are great boats, Pearsons, Cape Dorys, etc., in our price range 10,000 and under. The problem is that they either have outboards, or inboard gas. I know the explosion risk associated with inboard gas so I have all but ruled out inboard gas engines. I have been told that a following sea w'' an outboard is a big problem in heavy weather while trying to negotiate inland piloting (prop coming out of the water). We don''t want to give up our intended cruising grounds. I keep thinking of way back in the day when there were no reliable engines and such, and the mariners that made it happen. I''ve even read about a 16'' that circumnavigated with no engine (www.mavc2002.com/caledoniayawl.agere1.htm), a very interesting story by the way. I also realize that weather would play a major factor in when we could leave any port that we are in given the conditions. My question is.. Are we going to bite off more than we can handle by purchasing a 22''-25'' boat with an outboard to use in our intended cruising grounds? I know that we could use the dinghy''s outboard if our main outboard would die. Is there anyone who''s had experience with our intended actions? Thanks for the input. Bob P. P.S. - If anyone needs crew, my wife and I are available for varying lengths, monohulls up to 40''. Good Day all!
 
See less See more
#2 ·
808, I sailed some of the area that you mentioned of interest last year aboard my 26ft, shoal draft trailerable boat.I''m planning on returning this year and continuing on down to Key West,and out to the Dry Tortugas.It''s a great area to sail in. I put my boat in at Ft.Lauderdale,single-handed as far South as Key Largo,crossed the Gulfstream to N.Bimini,and then returned to Ft.Lauderdale.IMO,smaller shoal draft boats are ideal for the Keys. I was able to sail Hawk Channel or the Bay side very comfortably.My boat has an inboard diesel and it developed a minor problem close to Key Largo.I took the outboard off my dink and used it on the stern bracket that I had installed prior to the trip.The outboard did fine.There were a couple of times that following seas did cause some problems with the prop jumping out of the water though.I noticed this particularly at large harbor entrances.With shoal draft/centerboard type boats,there are several areas to cut between the ocean side to the bay side,and thus avoiding most of the problem.On the issue of gas vs.diesel, I personally wouldn''t take a boat off my "possible" list because it had a inboard gas engine.I think you have to be aware of safe practices for such an engine, and maintain it accordingly.I envy your move to the Gulf coast.A friend of mine keeps a boat at Punta Gorda and tells me the sailing around that area is great.Good luck with your move,and sailing.
 
#3 ·
There''s nothing wrong with inboard gas engines for your intended purposes but if you are buying a 25 footer with "all the accomadations we could acquire" then I would say that an outboard is out of the question for your intended cruising grounds.

To explain, A properly maintained inboard gasoline engine, while slightly more dangerous than a marine diesel,is still a pretty safe and reliable engine. In my lifetime, with one exception, every boat that I have ever heard of that has blown up or burned, has had a diesel, and usually propane. In sailing, people tend to be pretty selective about what they fear. These days people have a deathly fear of gasoline inboards but think nothing of carrying propane, a far more explosive material, in boats that lack the ''explosion proofing'' of a boat with a gas engine. The electrical systems on marine diesels are sealed so that they do not produce sparks and the carberators have backfire supressors so that the risk of a gas engine ingiting itself is fairly minimal. Gasoline boats have bilge blowers that are also sealed units which vacate any fumes in the bilge. Using reasonable precautions, running the bilge blower and sniffing the bilge, the risk of explosion is minimal. You can then probably buy a nice 27 footer with an atomic 4 in your price range and do very well for yourself. (There''s a huge difference between a 25 and 27 footer for what you are proposing)

Outboards are a pain in the neck for the kinds of thing that you are proposing. In the kind of short chop sometimes with no wind that you are dealing with in these venues, they are really exposed to getting dunked and then airborn, eventually leabing you with no wind and no engine. Some people recommend outboards in a well. In my experience these are the worst of all worlds.

There are a lot of good boats that should meet your needs (To name a few):

Albin Vega: You can often find one of these with a diesel for less than your budget.

Beneteau First 28: While Beneteaus take a bit of a hit in this country, the Frers designed 28 was a pretty nicely designed and built little boat.

Bristol 27: Nice boats in a lot of ways. I have spent a lot of time on these. I like the mid-1960''s model better than the later ones.

C&C 27:

Cal 27 or Cal 27-2 (Cal 2-27)

Cal 28:

Ericson 27: You''ll need to try to find a clean one but these can often be found with a small diesel in your price range.

Hunter 27 (Late 1070''s early 1980''s) While Hunters, like Beneteaus, take a lot of verbal abuse in this country, the 27 was a pretty nicely designed and built little boat. That said you need to find one that was maintained pretty well as these boats were sold cheaply and often allowed to go to pot.

Oday 27: While pretty low on this list you can find these very cheaply with inboards.

Oday 28: (try to find one before they went to a sail drive)Good little boats. I like the fin keel versions better than the K/CB.

Pearson 28

Pearson Renegade:

Pearson Triton: (Although the 28 is probably a better boat for what you want to do)

Soverel 28: These were really built for exactly what you want to do. Last time I looked there was one on Yachtworld with a diesel for $9500.

Tartan 27: This would be the Bee''s knees for what you have in mind. Whiel not all that fast, these are really good all around boats.

Yankee 28:

The point here is that you should be able to find a perfectly suitable boat within your price range, some with diesels, some with gas inboards. While smaller, older boats take more skills to sail in the places that you are considering, and certainly these older boats require a lot more maintenance skills and costs, they can be just as satisfying to own adn would be less expensive to own than much the much bigger boats that are the norm.

Respectfully,
Jeff
 
#5 ·
I agree that an inboard gas engine should not be a total deal breaker on an otherwise sound boat.

The explosion hazard is real and you need to maintain the engine correctly, only install electrical equipment that is safe around gas, and install a sniffer for the bilge.

The big disadvantage of gas is the limited range the boat has. A gallon diesel contains a lot more BTUs than a gallon of gas and a gas engine sends a lot of the energy it generates out through the exhaust as heat.

Although some people say they would not have a boat with a gas engine in it many routinely stick the dingy engine gas can in their lazerette and sometimes place the outboard engine there too.

Outboards are a pain in the butt. I sailed florida for years and the outboard I had was always coming out of the water when there was any sort of sea running. Couple that with a very short range and limited (at best) battery charging capability and you have a really strong argument against using an outboard as your auxillary engine.

If you use an outboard try to make it a 4 stroke as the gas milage is much better. Four stroke engines are really heavy, however.

BTW, you dont have to cross the gulf stream to have some wonderful cruising. Any place in the keys where cars can reach is as beautiful as places in the Bahamas.

If you do want to cross the stream you can just wait for the weather (so you will have wind) and start down in the keys so you will have a good shot at making it acrossed the stream before it carries you too far north.

John
 
#6 ·
I really disagree about the fuel economy of a gas engine vs diesel. Our Atomic 4 used to burn a little over a 1/4 gallon an hour which pretty much matched the fuel consumption of the smaller diesels that I used on similar weight boats. Atomic 4''s often had more horsepower than a small boat can absorb. When I hear of a boat getting noticably worse fuel economy from an Atomic 4 it was usually one in poor condition or a case where the engine is throttled up past hull speed.

Jeff
 
#7 ·
Jeff,

Several years ago I took a diesel mechanics course at orange coast college in southern california. The instructor was a guy named Terry Brown who was a local diesel mechanic. He seemed quite knowledgable. I was impressed enough to remember his name after 12 years.

One of the things he told us was that diesels are much more efficient than gasoline engines for two reasons.

1. the temperature of diesel exhaust is about 2000 degrees cooler than on gas engines so a lot of the energy generated in a gas engine is pushed out in the exhaust.

2. the energy content of diesel fuel is higher than for gasoline. The following paragraph is pulled from the web site "How things work"

Diesel fuel has a higher energy density than gasoline. On average, 1 gallon (3.8 L) of diesel fuel contains approximately 155x106 joules (147,000 BTU), while 1 gallon of gasoline contains 132x106 joules (125,000 BTU). This, combined with the improved efficiency of diesel engines, explains why diesel engines get better mileage than equivalent gasoline engines.

My experience with the atomic 4 has been different from yours. While the 2gmf diesel on my NorSea 27 gave me a cruising range of about 400 miles on 20 gallons, a friend of mine had somewhere between half and 2/3 of that on his ericson with an atomic 4. His boat was much lighter than mine and he was not pushing it when we cruised together. I was always the one playing catchup under power.

The engine on my norsea used less than 1/4 of a gallon an hour unless I really pushed it.

Diesel cars and trucks also get a lot more miles per gallon than similar sized gas powered vehicles.
 
#8 ·
Thank you for your thoughtful answer. I knew about the relative difference in the specific heat output of Diesel fuel vs gasoline and that gasoline produces less heat, but I had also understood that diesel engines do not combust the fuel as completely as gasoline engines and that the relatively large unburned hydrocarbons typically found in a diesel engine''s exhaust, meant that not as much energy was extracted from the fuel bringing the two fuels into parity in terms of energy extracted.

Beyond that, while heat is one measure of a fuel''s output, when you talk about reciprocating engines, the expansion and speed of expansion of the combusted fuel has more significance. It has been my understanding that gasoline actually imparts a greater amount of expansive force much more quickly than diesel during combustion for a given weight allowing it to produce more shaft horsepower.

Now some of this may be quite out of date. Most of my knowledge on this subject was self-taught during a period in the 1970''s when I was racing, and helping design and build racing motorcycles, including their engines. In those days I was scouring primary source research material on engine design. During that era, Volkswagen was developing small automotive diesels and thier research was available in SAE papers. Since they also owned NSU, (who was heavily involved with 2 stroke engine design in those days and racing engines were two stroke) I had gotten and read through almost all of Volkswagen''s available research papers. In actual practice, Volkswagen was not able to get better fuel economy out of thier small diesels compared to equal output gas engines.

Diesels are employed in trucks because they produce enormous amounts of torque in relationship to the horsepower that is being produce. Trucks need huge amounts of torque to move their heavy loads without having even more gears required. It is not a matter of fuel economy.

As to our comparative fuel economy figures, I apologize for starting that line of discussion because my example (or perhaps our combined examples)probably represents too small a ''scientific sample'' to really be meaningful.

In any event, any difference in fuel consumption for someone going over to the Bahamas is probably insignificant in the big picture. Obviously if fuel consumption is a concern then outboards should be elimated because dispite their apparent efficiency due to prop orientation, generally do not achieve the same fuel economy of a similar horsepower output inboard.

Respectfully
Jeff
 
#9 ·
The main problem with the gas motor is the ignition system. The points constantly need to be re-placed. When I bought my boat it had a 35 year old gray marine . It ran great when I could get it started and of course it had a mind of its own. When I decided to re-power the cost of retro-fitting a diesel was out of the question. I found somebody who re-manufactured the gray and I was a little sketchy about putting in another gas motor. You always meet some one who knows somebody who blew up. Anyway for the price of a new motor $2500 it was my only option. I also started to think this origanal gray still ran and if it has lasted this long I guess it is an okay motor. I have since had this motor in my boat for three years with electronic ignition and it has been brilliant. It is very quiet does not smell plenty of power and so far very reliable.I never mention now I have a gas motor because I am tired of hearing about everybody blowing up.-thomas
 
#10 ·
808,

Agreed that an inboard diesel is preferable, but your trip is possible with an outboard. Check this link for a fellow who traveled from NY to the Keys and the Bahamas on his O''Day 25 with an outboard. He had his troubles, but he made it. In fact, I just went sailing with him one afternoon in Key West earlier this month. I think the bottom line is how well YOU are up to dealing with an outboard for such a voyage. It''s doable, but not without some risks over and above using an inboard engine, whether it be gas or diesel.
http://www.knotink.com/Voyage/
 
#12 ·
Hello all, 808state here, (my name is BoB-"808", that''s what my friends call me). Thanks everyone for all the great information. It will really help me make the decision on what to buy. So we know the pros and cons of gas vs. diesel. The next question is, how available is gasoline at marinas, and is it more expensive than deisel? I know it probably wouldn''t be a problem finding in the Keys, SW FLA. What about in the Bahamas, or beyond? Don''t want to lose my boat on a lee shore or run aground in a blow because I was trying to find a marina with gas, ran out of gas, ran aground or be rolled, or worse. Thanks again for the input, really appreciated. Take Care, 808 state (Bob).
 
#13 ·
Dor the most part, gasoline is more readily available than Diesel. Prices differences vary with diesel usually being a little less expensive in the States. With the small amounts of fuel that you will be using on a boat that size the difference in price should be insignificant.

Jeff
 
#15 ·
Well I guess I will be getting the same rash of e-mail about gas engines. I have an Atomic 4 gas engine,you need to cary spare ignition parts.Coil,points and condenser,plugs,a spare fuel pump electric is the best way to go if you have the manual pump it cost about three hundred bucks to make it electric.A constant duty sealed bilge blower with a deep sump hose even two on seperate switches is better. I run one if any one is below while motering just to make sure no monoxide is building up in the cabin. The motors are simple by all standards and most problems can be fixed almost any place if you have a good tool box. One thing that is a negative is if you have to do any fuel system cleaning as in filter cleaning ect, the gas that may and will get spilled makes for a bad night if you have to get up and hit the blower every hour because the smell stays in the bilge for a whole day unless you hose it down and soap it out. Dawn dish soap works OK with lots of water.Don''t smoke in the cabin or light any open flames until the next day just to be on the safe side. Forget the outboard power plant they are for dinks only or fishing skiffs not sail boats. Also an Atomic will heat a water tank for a shower in short order while you charge the batteries you can descum.I always wondered about the name ATOMIC if that was because the explosion they made was that big or what?
However I have had hundreds of hours on boats with them and never a real problem even on one we discovered ten gallons of fuel from an old leaking fuel line in the bilge while under way and still came home ok. We were known as the bio terrorists after getting the fuel out of the bilge but things happen you can not help. I guess the key is maintanance and new is good for all reasons when it comes to gas.
 
#16 ·
I too have an Atomic Four, an early model in a Pearson Triton and have to give it a thumbs up. It was designed for marine use with very low compression ratios thus you don''t get the noise or vibration you get with a diesal.

The real beauty is any "shade tree" mechanic, myself included, can fix it. They are very simple engines and few things can go wrong with it that you can not fix with some basic knowledge and basic tools. There are over 40,000 of them still in use... I think that speaks for itself. I have left the points and condensor on mine since my thoughts are K.I.S.S.... generally if it is not firing it is simply a matter of using a piece of paper sack or a match book on the point and you are good to go again. (However, I do carry spares, as well as, Don Moyers bible-- just in case--- but the engine really is amazingly simple). I also have an old British Seagull on my dink, another oldie but goodie.

Most importantly, buy the boat you can afford and go now. There are numerous older boats in your price range and often you can find an old boat that simply needs to love to become a safe reliable home. Just today in the Annapolis paper was a free Catalina 27... they are out there, just keep looking and keep learning and planning. Fair winds. Ang
 
#18 ·
Speaking as a relative novice, I appreciate the simplicity of Diesel engines. I am no engine mechanic, not by a long shot, but with a bit of reading, I am able to understand my single cylinder Volvo Diesel. That''s a point I never reached on (gasoline) automobile engines. With all the other good reasons - already mentioned here - to go Diesel over gas, if I had any choice in the matter, the choice would be simple - Diesel.
 
#19 ·
Diesel all the way for me too.The older I get the more chicken I get.Sure a diesel will burn you out,but it will not set your boat off like a bomb,that is the real difference.A fire is not nice,but an explosion is definitely the clincher.I have been burned bad in a gas fire/explosion before.Thankfully it was not on a boat or I would probably of been finnished. Just the horror of a gas fire sways my opinion,anything burning is not good but gas is bad and untill you have actually experienced it there are few words that can describe the speed of which things get out of control.Where diesel engines shine when economy is the issue is when they have a light load applied.A big rig can sit overnight idling using next to nothing for fuel but a gas motor just chews it up.I have owned heavy equipment for years and like everything else some motors are now running with electronic timed /fuel injection.Just wait and it will be in all the boat engines as well.Talk about screwing around with something untill you make it more complicated and less reliable IMO.This conversation reminds me about heating your home with oil or natural gas.Sure you can get a leak with oil and have a problem,but natural gas for me if I have the choice NO WAY.
 
#20 ·
It''s important to note that besides the explosivity of gasoline there is igniteability issues. Put a match to gasoline in the open and it will violently burn. Put a match to diesel in the open and it will not burn. You need more concentrated heat to get diesel to burn.

If you do go with gasoline what makes a big difference in reliability is to have electronic ignition. I believe there are conversion kits for most engines if it hasn''t been converted already.

A little off the subject but mentioned previously was the fact that people will worry about gasoline but have propane stove systems. On my 28'' Ericson I avoid that problem by having an Origo alcohol unit. I think the safest of all cooking systems. No propane or CNG. No tricky lighting of pressure alcohol systems but the advantage of water extinguishment . Just the Sterno type cannister that I refill up on deck in case of spills.
 
#21 ·
I''m quite happy with my Atomic 4; it''s reliable, quiet, easy to work on, parts are available, and there is a great support community (see www.moyermarine.com). With electronic ignition and a sealed water pump, the engine is a dependable workhorse. As long as you pay attention to what you''re doing and be sure that your tank, vent, filters, lines, fuel pump, and carb are all intact, gas is no problem.
 
#22 ·
Alchohol is a good fuel for the weekend user and occasional cruiser. For long term use propane is awfully nice and much more versitile than alchohol. I used to have an Origo too, and it really is a good stove and served me well. On the new boat though, I sure do like cooking with propane and having an oven.
 
#23 · (Edited)
With respect to a gasoline inboard v. outboard, you will have gasoline in your boat either way. With the inboard, you will likely have a fixed tank and piping. With the outboard, you will probably have a portable tank with hoses.

As between the two options, a properly managed gasoline inboard engine seems preferable.
 
#24 ·
Goodnewsboy said:
As between the two options, a properly managed gasoline inboard engine seems preferable.
Powerboats use gas, cars use gas. Gas isn't the problem, but ignorance can blow you up. Run the blower, make sure the alternator is "marinized" (spark-shielded), double-clamp all hoses, and install a sniffer. Think twice about installing propane, or if it's a small boat, a Coleman stove on a plank in the cockpit plus a rail barbeque running those two-pound bottles seemed to serve us just fine in Toronto where the weather isn't as amenable as Florida.

I have rebuilt and installed an Atomic 4 in my 33 footer and it runs like a charm and is quite economical to boot. I actually REDUCED my gas tankage from 15 to 11 U.S. gallons because I was having trouble using a tank a season. Also, I wanted extra locker space for lines.

Given that I motor off the mooring, get head to wind, and then switch off and get to sailing, that's not surprising. I use about 3/4 gal/hr. at 5.5 knots, which gives me enough range to find a gas station anywhere. If I am motorsailing, I have refuelled enroute from jerrycans, but this is rare.

My new much larger boat has a fat diesel in it and enough tankage for about a thousand NM of range, but it has its own issues, primarily the availability of diesel (and its cleanliness) in certain places, and the fact that diesel engines, unlike gas, really don't enjoy the typical "motor in and out from the basin" scenario. They want to get nice and hot, and so ironically, I am leaving the engine on longer just to warm it up, knowing that the bearings will thank me for not switching it on for just 10 minutes in the cold April air to get beyond the breakwall. So I am burning more diesel than I'd like...because it's a diesel!

This is not a concern with the Atomic 4 anymore than it's a concern with an outboard or a chainsaw. Gas engines can bear short periods of activity. This characterizes a lot of sailboat use...otherwise we'd all have trawlers, right?
 
#25 ·
Gas or Diesel

If well looked after there will be no more problems with one or the other. If left to rot both will bite you.
Dirty gas will plug a filter, as will diesel. Water in the fuel will cause a gas engine to quit, repairable with some methanol and perhaps draining the float bowl. If water get's past the filtering system of a diesel it will destroy the pump, and most likely blow the tips off the injectors since the pressure required to atomize diesel fuel (about 14,000 psi) is enough to cause severe mechanical damage to the system trying to force the relatively high surface tension of water through holes that are almost too small to see. Here again the cost issue comes out. A carburetter and distributor rebuild (which you can most likely do yourself) is really cheap compared to a diesel injection pump/ injector rebuild/exchange. Also diesel fuel and everything it touches stinks. Moreover diesel fuel will grow a filter plugging organism extremely quickly if conditions are right rendering the fuel and all components of the system useless.
That being said, diesel, with a clean fuel system and semi regular oil changes will cause very few problems, and clatter away for a long, long time.
The higher BMEP (Brake mean effective pressure) of a diesel, combined with the higher calorific value of the fuel, and more importantly the fact that diesel fuel will burn in the cyl. no matter how little of it is injected mean better potential economy. Gasoline needs to be mixed with air at a very specific ratio, (called the stoiocheometric ratio, about 15:1 air/fuel by mass) in order to burn. Generally primative carburation systems lean toward the rich side in order to assure combustion and to keep the threat of detonation low at all throttle settings. Diesel injects a specific metered amout of fuel each cycle, dictated by the the RPM the governor is set to achieve. (If the engine cannot achieve the RPM that the governor is set at because of loading then the pump will run at full rack, injecting as much fuel each cycle as the the pump is able whether or not the engine can burn it competely or not, passing the unburned fuel out the exhaust as black smoke/soot. The point being that if operated below the tourque peak a diesel will always be more efficient than gasoline. I'm not sure if fuel savings alone would ever equal the much higher initial cost or rebuild cost. Diesels are, of neccessity built more robustly and hence can expect a long life. The Atomic 4 was designed with very low component loadings so it too can expect a long life.
Treat the fuel system for gasoline with the same respect that you would treat a pressurised propane system. Use the best quality components on every joint and fitting and check them annually or better. No fumes, no boom!
As far as an outboard is concerned, they can be a pain. They put weight where it doesn't belong. Without electric start they are usually in a most awkward place to yank in a rope. They do, however have a couple of advantages over inboards.
1) The prop, etc. spends all of it's time when not spinning out of the water so no marine growth, especially in the tropics.
2) they can be had relatively cheaply, especially two strokes.
3) they work really well in reverse, especially if centered behind the rudder and with the tilt locked down. The prop wash past the rudder allows directional control without sternway, priceless.
4) If you can put an extension handle so that they can be steered from over the pushpit they are magic for tight manouvering.
5) Often they run from portable tanks so that the entire cumbustable thing becomes almost a non issue if the tanks are in a vented cockpit locker.

Just my two cents worth.

Feetup
 
#26 ·
Talk about legs! Did anyone notice the timestamps on the entries on this thread?
I have owned both gas and diesel inboards. Both are quite reasonable, but you have to have a different set of operating habits for each.
I have never met a cruising sailor that was happy with an outboard in open water. When you start pitching in a seaway you lose the propulsion just when you need it. Also most outboards can't handle the battery charging that a cruising boat needs. Leave the outboards to the racers to get back into their slips.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top