Diesel vs Outboard

[Bruce Bett]

A number of you have commented that your outboard props have rarely if ever come out of the water. I agree. That has been my experience as well. I did have an experience in big waves, which makes me a little nervous.

A few years ago I was motoring my CD25 on a 30 mile passage on Lake Erie. At the time I estimated the waves at eight feet. I really don’t know how big they were but I was impressed. I did NOT have a problem with the prop coming out of the water, but a couple of times at the bottom of a particularly big wave the water would rise a little too high in the well and the engine sputter and nearly stall. It did not stall and we completed the passage with no looses except for our lunch.

I’m not sure just what it was that was getting wet, but after that experience I worry more about my outboard at the bottom of the waves than at the top. Do any of you have any insights or similar experiences?

Bruce Bett
Sostenuto
CD 25 #496

Hi Listers,

I'm considering a CD in the 25D to 27 range as my next boat. Can anyone speak as to the pros and cons of a Yanmar 1GM in the 25D and 27 as opposed to a 10hp outboard in the 26 transom well? The diesel has great fuel mileage, a huge alternator, and lower weight in the hull. However, I read the single cylinder 1GM is taxed pushing the 25, and undersized for the 27. On the 26, the outboard is easily replaced or serviced, but must be a bit inconvienient to use tucked away in it's well, and the prop sits near the waterline.
Also, does having the motor well in the 26 compromise on cockpit size?
I notice the CD25D and 26 are close in displacement, would a 10 hp 4 stroke in the 26 push the boat better than the 1GM in the 25D? I wonder if both boats have about the same sailing caracteristics, given alike sails.

Thanks,

MB

bettb@macomb.cc.mi.us

[chuck yahrling]

Hi Listers,

I'm considering a CD in the 25D to 27 range as my next boat. Can anyone speak as to the pros and cons of a Yanmar 1GM in the 25D and 27 as opposed to a 10hp outboard in the 26 transom well? The diesel has great fuel mileage, a huge alternator, and lower weight in the hull. However, I read the single cylinder 1GM is taxed pushing the 25, and undersized for the 27. On the 26, the outboard is easily replaced or serviced, but must be a bit inconvienient to use tucked away in it's well, and the prop sits near the waterline.
Also, does having the motor well in the 26 compromise on cockpit size?
I notice the CD25D and 26 are close in displacement, would a 10 hp 4 stroke in the 26 push the boat better than the 1GM in the 25D? I wonder if both boats have about the same sailing caracteristics, given alike sails.

Thanks,

MB

Regarding part of your question, I think a one-lunger may suffice for a CD-27 providing you are not bucking big currents or big chop on a regular basis. Can't comment on the 25D; ask Lee Hodsdon how he likes his CD25D engine. I have a 2GM (rated 10HP) on my CD-27 and normally cruise it at 2500 RPM to reduce noice and vibration, and because in anything but smooth water it seems most efficient there. That gives me about 4.5Kts avg hull speed. Looking at the Yanmar manual, the HP rating for the 2GM is 6-8hp at 2500 RPM. That compares with the max rating of a YSM-7 or 1GM. My boat has the stock Michigan Sailor two-bladed prop.

Our CDs have a lot of mass for their size which helps battle chop when underway, so getting the max power through the prop and into the water is more critical when trying to accelerate or to buck swift currents, right into the wind, with no sail power available. When motor sailing in normal conditions, you may not miss a larger engine, particularly if you can get good drive out of your sails.

A long-shaft outboard ought to do in most conditions. Even with a diesel, in rough conditions - especially when heeled away from the raw water pickup - you have to be mindful about starving the cooling water intake. On the smaller diesel CDs I've seen, the intake is on the starboard side of the keel, positioned on the deadrise such that it's a foot or two below the surface. Over-heeled on starboard tack with a good chop you could get some starvation and a hot running engine. I've seen it happen to a CD-33, for example.

I chose a boat with a diesel for the traditional safety and reliabilty reasons. But I think that with the convenience and reliability of modern four-stroke gas engines, it's hard to make a compelling point to buy based only on aux engine type and HP. My advice (to myself) is always to buy the biggest boat that's reasonable for the intended use, because it gets smaller very quickly once it's in the water and a few other people go with you. There are always tricks you discover to make it go better in a pinch. Hope this helps.



cyahrlin@cisco.com

[Bob Malinka]

Regarding part of your question, I think a one-lunger may suffice for a CD-27 providing you are not bucking big currents or big chop on a regular basis. Can't comment on the 25D; ask Lee Hodsdon how he likes his CD25D engine. I have a 2GM (rated 10HP) on my CD-27 and normally cruise it at 2500 RPM to reduce noice and vibration, and because in anything but smooth water it seems most efficient there. That gives me about 4.5Kts avg hull speed. Looking at the Yanmar manual, the HP rating for the 2GM is 6-8hp at 2500 RPM. That compares with the max rating of a YSM-7 or 1GM. My boat has the stock Michigan Sailor two-bladed prop.

Our CDs have a lot of mass for their size which helps battle chop when underway, so getting the max power through the prop and into the water is more critical when trying to accelerate or to buck swift currents, right into the wind, with no sail power available. When motor sailing in normal conditions, you may not miss a larger engine, particularly if you can get good drive out of your sails.

A long-shaft outboard ought to do in most conditions. Even with a diesel, in rough conditions - especially when heeled away from the raw water pickup - you have to be mindful about starving the cooling water intake. On the smaller diesel CDs I've seen, the intake is on the starboard side of the keel, positioned on the deadrise such that it's a foot or two below the surface. Over-heeled on starboard tack with a good chop you could get some starvation and a hot running engine. I've seen it happen to a CD-33, for example.

I chose a boat with a diesel for the traditional safety and reliabilty reasons. But I think that with the convenience and reliability of modern four-stroke gas engines, it's hard to make a compelling point to buy based only on aux engine type and HP. My advice (to myself) is always to buy the biggest boat that's reasonable for the intended use, because it gets smaller very quickly once it's in the water and a few other people go with you. There are always tricks you discover to make it go better in a pinch. Hope this helps.

====================
Hi Chuck:

Don't know if you remember me but I'm the fella who bought your alcohol stove for parts for my CD25D. With regard to your comment about the intake for the raw water cooling on the CD25D. The kingston valve is located on the starboard side and is far enough down that I have never had any problem what so ever with it not drawing water for cooling in rough weather. On the CD25D we are talking of it being near the bottom of the boat and mine has a strainer on the outside which I installed to filter out debris and eel grass. We have motored with the diesel in some pretty rough seas in Buzzards Bay, Block Island Sound, Long Island Sound, the Atlantic Offshore and the Great South Bay here on the south shore of Long Island the last 15 years or so. Because of the shallow waters on the Great South Bay and the strong prevailing southwest breezes we usually get large waves in high frequency (steep and short intervals). I would think that if the water cooling problem were to exhibit itself it would happen in those conditions, however it has not. I also don't believe it is good practice to motorsail in high wind conditions that would allow the boat to heel to the degree that you are describing as the motor would starve for lubrication oil. With the boat heeling to the degree that you described the lubricating oil would not be sufficient to draw a prime in the crank case. In order for the kinston valve to draw air at the bottom of the boat it would translate into a rather steep heel where the boat would be on it's ear with toerail submerged. If this is the case one of the following should be done: reduce sail by reefing and continuing sailing without motoring, or lower sail and proceed under motor only. My general rule is that if you have that much wind to heel the boat from your quarter then you should be sailing and not motoring. Our boats sail much faster even to windward in a good breeze than motoring unless the wind is dead on the bow in your teeth. Hope this makes clear what conditions would dictate the possibility of drawing air through the kinston valve on the CD25D.

Bob



Ranger1442@hotmail.com

[Dana]

Some interesting discussion on this topic. I have sailed both the CD25D and CD26. Have owned a CD26 for 16 years now. Same Yamaha 9.9 HP four stroke (25 inch skeg, 15A alternator) that I bought with the boat. Used to sail Block Island Sound etc. before moving here to the Chesapeake.

Both boats sail the same. The 1GM can have quite a bit of vibration. Many have noted that the Yamaha is very quiet. The chief reason for me choosing the CD26 over the CD25D, at that time was cost. $26K w/engine vs. $38K ++ for the CD25D...these were for new boats.....
Interiors are very different....the CD26 outboard has tremendous storage area under the sink/in the lockers without the engine. There is only 1 sink thru hull drain. Outboard control arm can "drop" into cockpit for ease of control...plus the lack of diesel smell and lack of water in the bilge is deeply appreciated by my wife..we made a waste paper trash bag holder "cage" out of the bilge access cover...the bag fits right in and it is very convenient.....but I have made my own modifications for the outboard and do all of the yearly maintenance to keep it tip top.....An 11" diameter, 25" skeg, 6-1/2" pitch, three bladed slow turning (four stroke) outboard prop does wonders for thrust power. Never had this one come out of the water..




[img]http://members.aol.com/darenius/CapeDory/cd26_1.jpg[/img]
darenius@aol.com

[Ross Williams]

we've owned a CD26 outboard model for 1 season. We love the boat. My preference is an o/b since I'm not that mechanically inclined. Friends with both atomics and diesels seem to spend a fair amount of time tinkering with the engines, shafts etc. To me this would be writing check after check since I wouldn't be doing it myself. Pulling the outboard out of the well for an occasional repair and annual winterizing isn't that big a deal. Our boat came with a 10hp, 2 stroke Tohatsu. More than enough power for the boat. Close to full throttle the boat will do approx. 5.5 knots in the right conditions. Haven't had any issues with prop cavitation or coming out of the water but can't say that I've had the boat out in any extreme weather conditions. If you do go for the outboard, the one strong recommendation that I would have is make sure that it's a 4-stroke or you'll probably be shopping for one soon. A 2stroke outboard in the well is way to noisy for my liking. We made it through 1 season of shouting at each other while powering and are now shopping 4stroke models to have a quieter 2nd season. We love the layout of the CD26 and the way she sails. I think all the boats that you are considering are solid,beautiful safe cruising boats. As someone already said, it just depends on your personal aux power preference and what your long term plans are with the boat. Have fun with your search! Ross



rosswilli@aol.com

[John Vigor]

Bob, I'd be interested to know what size prop you're using to get such good performance out of your Yanmar 1GM. I have the same setup in my 25D, but can't get more than 5.25 knots with a 12 x 11 three-blade prop, which I suspect is overpitched because I can't reach top revs. Are you by any chance using a 12 x 9 three-blade, which I think is the right one? If so, do you know the make?

Thanks

John Vigor
"Jabula" CD25D #73

I'm considering a CD in the 25D to 27 range as my next boat. Can anyone speak as to the pros and cons of a Yanmar 1GM in the 25D and 27 as opposed to a 10hp outboard in the 26 transom well? The diesel has great fuel mileage, a huge alternator, and lower weight in the hull. However, I read the single cylinder 1GM is taxed pushing the 25, and undersized for the 27. On the 26, the outboard is easily replaced or serviced, but must be a bit inconvienient to use tucked away in it's well, and the prop sits near the waterline.
Also, does having the motor well in the 26 compromise on cockpit size?
I notice the CD25D and 26 are close in displacement, would a 10 hp 4 stroke in the 26 push the boat better than the 1GM in the 25D? I wonder if both boats have about the same sailing caracteristics, given alike sails.

Thanks,

MB

This issue has been debated here on the list before just take a look into the archives. To me the choice is very clear having been sailing on the water all my life. Having been there and done that with outboard and with a diesel it is my opinion for safety considerations that gasoline has no business on a sailboat at sea. I do all my own maintenance having worked as a diesel service manager and crewed as first mate aboard commercial fishing vessels in another life. I have had my fill with gas tanks leaking while at sea not to mention the smell of an outboard and the noise. It has been 10 years since I last owned an outboard but my recollection on the reliability aspect also does not sit well with having an outboard in a sailboat. I remember always having to grease or replace parts because they were corroding from saltwater and replacing motor mounts, water pumps, lower ends because of saltwater leakage into the lower gear unit, and tune ups.

We have the 1GM Yanmar in our CD25D and I would not give it up for the world. Over the years beginning from 1986 since we have had our CD25D it has gotten us through some pretty rough water without so much as a blink. Gone are the cavitation problems when it gets rough and all the other unpleasant things that come with an outboard. For reliability, safety, durability, maneuverability, maintainability and just plan old frugalness on fuel the diesel will be my choice all the time. Our 1GM is rated at a modest 6.5 hp and it is certainly not underpowered for the CD25D. That little one cylinder diesel will push the CD25D to hull speed until it produces a large wake which on our knot meter indicates to be well over 6+ knots. We have motored through inlets that had 4 - 5 knot currents in the company of other much larger yachts 35 to 40+ feet and received comments on how fast our CD25D motored into such a strong current. The 1GM likes to run and will go all day or night on very little fuel. We have made passage offshore from Amityville, NY on the Great South Bay, Long Island through Fire Island Inlet to Block Island, which is over 130 miles nonstop running under power because of the lack of wind and used just 5.5 gallons of diesel fuel. We have a 12 gallon tank on our CD25D and based upon my experiences with this boat it probably could motor clear around Long Island on one tank of fuel. Please keep in mind that Long Island is over 125 miles long. We use our boat quite a bit during the summer and it is very rare that I ever get through more than one tank of fuel for the summer. The problem I have is not using the fuel which goes stale sitting in the tank. To offset this problem I make sure to use cetane boost, fuel store and biocides to keep the tank clean. Correspondingly I also make sure to change fuel filters regularly in accordance with the manufacturers recommended schedule.


Bob
s/v Ranger
CD25D #144
Homeport: Amityville, LI., NY.

jvigor@qwest.net