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Old 08-08-2015, 04:13 PM   #41
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Another big negative for diesel OBs is weight. Putting the engine "outboard" of the boat aft is very bad for weight distribution. Center of the boat is the best place for something that heavy. OBs do it but they are lighter than a diesel would be. But the weight of the engine may help keep the small prop in the water.
A 200 hp Oxe diesel right now is 650 - 700 lbs. vs. 500 lbs. for a Yamaha 200 hp.

Now, Klaxon has a 40 hp multi-fuel which is only 172 lbs. and actually lighter than a Yamaha 40 at 200 lbs, but their 40 hp diesel weighs 275 lbs.

Mercury actually developed an 175 hp Optimax Diesel for the military.

Weight is often the issue with diesel, even on inboards. We like jet Rib's. A Williams 445 Diesel weighs 1851 lbs vs. their comparable 445 Gas which weighs 957 lbs. The same hp gas is as a result significantly faster in that boat. In principle I would far prefer carrying a diesel version than a gas model, both for safety and convenience. However, the weight difference is huge on an under 15' tender.
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Old 08-08-2015, 06:32 PM   #42
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Maybe Chris(Sea Ranger) is on to something here. Sea chesst are a common feature on many boats. So, a big sea chest, totally enclosed, with hydraulic lifts, mounting a couple of OBs, air piped in, pretty much infinite trim possibilities. But then we are getting pretty close to an "outboard pod drive".
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Old 08-08-2015, 06:35 PM   #43
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Yanmar made one and still may market it outside the U.S. I saw one at the Yanmar dist in Seattle about 10 years ago. It was about the size of a 90hp OB but only made 35 (or so) hp. I read about them being extremely noisy somewhere else. Now I recall that the price wash extreme sticker shock. But this was 10 or so years ago.
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Old 08-08-2015, 06:54 PM   #44
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300HP Diesel outboard
Maritime Propulsion | New 300hp (224 kW) Diesel Outboard
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Old 08-08-2015, 07:55 PM   #45
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Soooo - In addition to the many pros and cons hashed over in this thread... for having OBs powering larger boats... this also begs the question of fuel usage comparison to either gasoline or diesel IB marine engines. Will OB's provide better mileage for same cruising performance?? What stats on this question are available - do tell!

Couple of notes I make:

1. Trim tabs would not be needed at all - Yippee!
2. However, really expensive experience if boater backs into a dock or other solid item with OBs at furthest rear. Would not take much for a 10 to 30 ton boat to fully crush the OBs instead of just banging up a repairable swim step.
2a. Speaking of swim steps... I like mine clear for swimming.
2b. Guess OBs could be built into a resessed transom area and have swim step still open for swiming as well as to protect the OBs if backing into a dock happens.
2c. But then the OBs begin to take up inner boat room... just like IBs. And with so much weight placed on stern instead of generally centered in boat's lowest bilge confines while acting as a sort of ballest.

OK - by writting this rambling post - I've decided to keep my twin screw IB straight drive Tolly just as is!

Whew... knew this would be the outcome before I even began writing!
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Old 08-08-2015, 08:43 PM   #46
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This was a 65 Viking that used outboards ( 2 Yamaha 250hp 2 strokes) to get it back to a rebuild facility after sinking. It also sank on the way back. Although impractical in many ways at the moment for heavy displacement boats I can see in the future someone designing an outboard for just such a purpose.
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Old 08-08-2015, 09:23 PM   #47
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This was a 65 Viking that used outboards ( 2 Yamaha 250hp 2 strokes) to get it back to a rebuild facility after sinking. It also sank on the way back. Although impractical in many ways at the moment for heavy displacement boats I can see in the future someone designing an outboard for just such a purpose.

Yep, it's here in Fort Lauderdale. Pretty goofy looking as one side yellow and the other blue.
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Old 08-08-2015, 09:55 PM   #48
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This was a 65 Viking that used outboards ( 2 Yamaha 250hp 2 strokes) to get it back to a rebuild facility after sinking. It also sank on the way back. Although impractical in many ways at the moment for heavy displacement boats I can see in the future someone designing an outboard for just such a purpose.
WOT = 5.5 knots.???
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Old 08-08-2015, 10:49 PM   #49
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[QUOTE=healhustler;356414]Those are very interesting designs, including a 35 ft. sedan that even Eric would look good in. Thanks for posting the link.[/QUOTE

Your welcome!! I agree interesting and yes the sedan was interesting also
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Old 08-08-2015, 11:27 PM   #50
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Power a trawler with outboards? Heck yea, can be done. You can also power a fine road car with a couple of lawnmower engines.... Both will move under power.
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Old 08-08-2015, 11:50 PM   #51
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Quote:
Originally Posted by manyboats View Post
...
Another big negative for diesel OBs is weight. Putting the engine "outboard" of the boat aft is very bad for weight distribution. Center of the boat is the best place for something that heavy. OBs do it but they are lighter than a diesel would be. But the weight of the engine may help keep the small prop in the water.
Midship placement of an outboard would have serious consequences on a boat's living accommodations.
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Old 08-09-2015, 04:35 AM   #52
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Check this article out

http://www.trawlersmidwest.com/pdf/e...er_article.pdf

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Old 08-09-2015, 07:10 AM   #53
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"which makes me hope we see diesel outboards in my lifetime."

Far more likely that you will see an outboard that eats diesel , JP5 ., kerosene , but is spark ignited , not compression ignition.

It will weigh what a gas OB does , and can use denser less refined (tho very clean) fuel.

Same HP/ gal as todays diesel, esp if turboed .
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Old 08-09-2015, 10:07 AM   #54
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IMHO

The “Eco Trawler” at 8’ beam with several other limitations on comfort/usability while on the water is just not my bag. Also, towing a 33’, 7000 lb. dry weight (probably closer to 10K lbs. fully loaded) boat around the country is likewise not my thang! Following quote from article [using a ton truck as example] seems iffy at best… regarding ongoing towing reality: “Ken and Karen Schuler of Trawlers Midwest reported no problems after trailering the boat fully loaded with cruising gear from Wisconsin to Annapolis, Maryland, behind a Ford F-150.”

NMPG is not bad though. 2.8 knots at 7 nmpg is fairly inexpensive… but you may get old before arrival to anywhere… better not be fighting a current! – LOL Can’t help but to wonder the stats on next line; i.e. 1500 rpm, 4.1 knots, 0.4 gph (same as line above at a 50% less in rpm) – and now, on this line, the boat gets 10.2 nmpg 30% better than the – 7.0 nmpg in line above???

There may be a class/age-group of people who would like to have this boat for use. I feel the market is limited.


RPM KNOTS GPH NMPG RANGE*
1000 2.8 0.4 7.0 392
1500 4.1 0.4 10.2 571
2000 5.6 0.8 7.0 392
2500 6.8 1.2 5.7 319
3000 7.7 1.9 4.1 230
3500 8.5 2.9 2.9 162
4000 9.3 3.8 2.4 134
4500 10.3 4.7 2.2 123
5000 12.3 5.7 2.2 123
5500 14.8 7.0 2.1 118
6000 15.7 9.2 1.7 95

LOA: 33’ 0”
BEAM: 8’ 0”
DRAFT: 1’ 9”
DISPL.: 7,000 lb.
FUEL: 70 gal.
WATER: 23 gal.
POWER: Evinrude E-Tec 50 hp outboard (x2)
PRICE $123,000 base, $230,000 as tested with twin engines, cruising interior, electronics.

CONCLUSION [quote from article]
"The Eco Trawler 33 is a synergy of unusual features with a unique and likable result. It is a strong coastal cruiser that is nicely suited to the Great Loop or the Bahamas.

While its length is greater, this neat little cruiser has about the same interior space as a conventional, beamy, planing 28-footer. However, when the weather kicks up or when you pull up to the fuel dock, you’ll see a big difference in its favor.

If you tire of the place you are cruising this month, load your Eco Trawler 33 onto the trailer and go somewhere else, even places only accessible by land."
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Old 08-09-2015, 10:37 AM   #55
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Midship placement of an outboard would have serious consequences on a boat's living accommodations.

Sure... but imagine in a typical cockpit location, slightly ahead of the transom. but covered with cockpit sole, maybe a removable lazarette capsule, etc.


Wouldn't have to a the same form factor as a current "outboard -- could be a normal engine, in it's own suitably waterproofed housing, with submersible drive leg structurally attached.

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Old 08-09-2015, 11:31 AM   #56
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Interesting. That Eco Trawler gets the exact same burn rate as my 38x12' 14000lb with 450 Cummins. 7.7kts at 1.9gph. Twice the weight, same burn. And at higher speed of 18kts it gets about same burn rate as the Eco does at 15.7. I've never run long enough at 15kts to get a burn rate.

There is something to diesel efficiency!!!

Note that the 50hp at full power is burning 4.6gph for 50hp, for a whopping 10.9hp/gph. Probably a bit better at mid range, but would need a dyno to measure that.

Not too "eco" at all. Unless you are ok with 5.5kts, which is really slow. Put some little Yanmars in there and you might have something "eco".
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Old 08-09-2015, 11:32 AM   #57
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Sea Dories? They are a flat bottomed skiff w a cabin tacked on. Great boats but they are what they are. Sea Dory even said "The Trailerable Trawler" in their adds. Rediculous.
C-Dories started as...dories. You can argue that a dory is a skiff with a cabin, but what's the point?

Anyway, while the first C-Dories did have flat bottoms, all boats since the late 80s have had a shallow V. And all C-Dories have had cabins, even the little 14s.

So they've been in production for more than 35 years. They started as wood and moved to all glass. While they are predominantly cruisers, I'm going to go out on a limb and say that more fish have been caught from C-Dories than any other manufacturer discussed on this site. Maybe more than ALL of them.

And I'm further willing to assert that more C-Dories have done the Great Loop than any other manufacturer. Part of that may be because they can be towed to the Loop, just like 10 to 20 of them get towed to Lake Powell every summer. And get towed across the country to cruise to Alaska. Or Mexico.

Are they trawlers? I'm not going down that rathole.

But with a long production run, traditional styling, economical cruising, wood then fiberglass - in spirit, they're closer to pocket Grand Banks than anything else. Oh, and they're even available with single or twins (I had twin 40hp Hondas on a CD22). And they have probably the strongest owners forum of any manufacturer, ever.
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