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Old 12-20-2017, 04:58 PM   #81
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Whaler has a 42 footer and Grady White has a 37 footer that are outboard powered. I know they aren't trawlers by any means but obviously some manufacturers think outboards are applicable to off shore, too big to trailer boats.

The Whaler has quad 300 hp engines. At WOT it burns 120 gallons per hour !!!
Nearly all builders of center consoles have outboard powered boats up to 42' and there are center consoles up to 53' now.

I had never owned an outboard in my life until a couple of years ago, not even for a dinghy. We bought a 39' Contender with triple Yamaha 300's for the use of our boating and management staff and crew. Maybe part of the reason we have a burning desire for a truly fast boat as our fastest, a Riva only hits 42 knots and the Contender can go flying past us at a gentle cruising speed since it's max is 57 knots.

I believe outboards have a place in trawler type boats, medium sized boats designed for long cruising. There are a few builders such as Rosborough and now Great Harbour with efforts up to 35'. There are others with "pocket trawlers." Sea Ray now has a Sundancer 320 with outboards. It sleeps up to 4 and has triple Mercury 250's. Perfect boat for someone wanting to do overnight cruising on a lake or river. Not really for coastal.

I don't believe we've come close yet to seeing what can potentially be done. We have small, not really seaworthy, trawler types with outboards, with small engines. We have center consoles with very large outboards and quite seaworthy. The Sea Ray Sundancer is somewhere in between. Outboards continue to grow. Now Volvo owns Sevens with up to 627 hp.

I think there are two huge potentials. First is a nice semi-displacement or even planing cruising boat with large outboards and the living platform you'd expect in a 40-50' trawler type cruiser. Second is a full displacement or semi displacement, more a Grand Banks type using outboards, probably a work type outboard design built for torque and thrust not top hp or even a diesel outboard if one shows up that is really marketable.

Outboards have taken over a large segment primarily because of price. By outfitting large center consoles with outboards, we've already seen the impact on the small sportfisherman boats. We've seen it in family boats too. Outboard have taken over where sterndrives once held.
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Old 12-20-2017, 04:59 PM   #82
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We saw this in Dinner Key Marina several years ago. The owners weren't around unfortunately. It looks like some thought went into the outboard mounting bracket.
Lots of people sport 9.9hp outboards on their swim steps up here for salmon trolling, and as a "get home or at least to a safe place" engine. (Several reasons include; no towing services, sometimes don't see another boat for days, and can be out of radio contact up long & twisty mountainous inlets).
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Old 12-20-2017, 05:06 PM   #83
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Hclews, nice!

Was the Acadia built for an OB engine or was it a retrofit? What HP and cruise speed/fuel numbers?
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Old 12-20-2017, 05:12 PM   #84
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Larry....was that a back up system, or the main propulsion do you think ?? Was there steerage linkage ??
I was thinking the OB was the main. It looked like too much work went into the installation to be a get home. And as I remember it there was steering linkage. What they did with the boats rudder? My guess, with the OB, the rudder may have been an extension of the keel if it was locked or some how tied into the main steering?

I can see the concept for a weekend, coastal cruiser vs repowering.
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Old 12-20-2017, 05:14 PM   #85
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Hclews, nice!

Was the Acadia built for an OB engine or was it a retrofit? What HP and cruise speed/fuel numbers?
Built both ways.

Builder's performance numbers with 200 hp Suzuki.

3000 RPM 12 knots 3.4 GPH
4000 RPM 19 knots 4.6 GPH
4500 RPM 22 knots 7.4 GPH
5000 RPM 25 knots 10 GPH
5500 RPM 30+ knots, no more data shown.
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Old 12-20-2017, 05:44 PM   #86
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Some of these Kurt Hughes designs would be contenders.
One of the 50ft ferries does 20knots with 30pax and 70hp/side.
Should manage fine with a couple of people and their liveaboard stuff.

Kurt Hughes Multihull Design - Catamarans and Trimarans for Cruising and Charter - Passenger Ferries
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Old 12-20-2017, 06:00 PM   #87
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There is no such thing as an OB trawler.

Putting an OB on an old GB will make a powered barge out of it. And I’m not trying to be critical of it. It would be fine for short local runs on flat water. It would burn four times as much fuel.

It would be easy to maintain and have perhaps better maneuverability. As to it’s noise level it may be required to run the engines very hard like a sailboat bucking some current. But at very low speeds it would be quiet and void of vibration. But w multiple engines there may be some harmonic vibration.

How many engines you employ may have a lot to do w prop blade area tp power ratio. Four or five smaller engines may be more efficient.

So as a harbor party barge I see no problems. But not operated as a trawler. Outboard power is not suitable for a trawler.
Installing outboards on a GB in particular would not only decrease the value of the boat if you put it back up for sale. Or the worse part for me would be the boat would be a pig to handle at slow speeds and around a dock.

The wheels on outboards are so much smaller than conventional inboard engines, and will be biting in turbulent water when you are attempting to turn it around in tight areas.

The plus sides for using an outboard or duel outboards on trawler style hulls is that you can get in more creeks as a rule than most inboard boats unless of course the boat is custom built with a tunnel or tunnels in it.

But also with the new four strokes, they really do not like to be run at slower speeds for long periods of time. They will load up and not be as maintainance free or cheaper to maintain as you would think.
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Old 12-20-2017, 06:44 PM   #88
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Ben,
I’ll bet he had that engine at home and the diesel went belly up and he couldn’d affort to fix or replace.
We saw pics of this boat underway some time back on another thread about this.
I don’t see any linkage but would like to hear if it did.

Scratch,
First time I’ve heard of a 4s loading up.
As to maneuverability remember the OB throws it’s thrust to the side. Like having a stern thruster. And if you had a bow thruster ?.... BUT it would be nearly impossible to stop or slow down except very slowly. And w a down wind and a spot of current may be impossible.

BandB,
Outboards could be more useful on bigger boats if they started building lower units w space for bigger props and lower gear ratios. Not before IMO.
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Old 12-20-2017, 06:57 PM   #89
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...I’ll bet he had that engine at home and the diesel went belly up and he couldn’d affort to fix or replace...
Eric: Than would be my guess but I like the yankee engineering. Not a bad solution and look at the extra space in the ER assuming they took out the old iron.
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Old 12-20-2017, 07:43 PM   #90
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What are you think’in Larry re the engine room space? 1200 gallons of gasoline?
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Old 12-20-2017, 08:33 PM   #91
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What are you think’in Larry re the engine room space? 1200 gallons of gasoline?
Beer and maybe a few to several hundred gallons of fuel? I’m not sure he needs more? If the boat is used as the majority of our boats are in that size range, he may have plenty of capacity? For a weekender or day trips? I have no idea but maybe a 100-200 mile range?

We use to have a Chris Craft with a 350/250 hp(?), inboard granted, but only carried 50 gallons of gas. We’d leave from Tacoma for Port Townsend or Laconner, based on the trip for the first fuel stop. Once I thought we could make it to Port Angels. We just made it past the USCG Station and when we ran out of gas.

Capacity and range, it’s all how you use the boat I guess.
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Old 12-21-2017, 05:45 AM   #92
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For comparison and my thinking and observation, IMHO the GB 42 footer weighs in around 35,000 lbs. A center console Yellow Fin 42 weighs in around 16,000 lbs. You will be attempting to move a much larger mass, vertically and underwater mass by using even the current state of the art outboards. By themselves the outboards will need higher rpms to move and turn the boat from a standstill, not withstanding the any current that's present. So you will have more turbulent wash simular to what you would be doing with an outboard in a barrel.



While the outboard may send water outward, the boat still needs to move away at a greater rate than possible using traditional outboards these days. Your wheels are only so big. I observe this will a kicker on my older sailboat in a simular setup with an undersized motor for the size of the hull The newer Suzuki outboards are using duroprops now days. This is showing an increase in performance for the newer center console boats in the repower from even the 300 hp. Yamaha outboards.



Now there are set ups with thrusters mounted in the sides of transom brackets, some built into the hulls of the newer builds that will assist with the outboards to maneuver the boat better along with the standard bow thruster setup that’s fairly common these days. .But if you truly want a bastardized GB, take those inboards out and add the outboards.
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Old 12-21-2017, 05:52 AM   #93
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And for kicks, if you are looking for some reading during the winter time,,,


https://www.thehulltruth.com/boating...outboards.html


Now where is my bag of popcorn..
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Old 12-21-2017, 06:02 AM   #94
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A conversion to a modern small gasoline engine would seem simplest and still be effective.

" IMHO the GB 42 footer weighs in around 35,000 lbs."

This is about 15 tons of displacement so 30-45HP is all that is needed for normal displacement speeds.

Many small car engines can provide this level of power with good fuel economy.

A diesel in fine condition might be able to make 20HP from a gal of fuel, if run at just the right speed and load , but most produce 15 hp/gal.

This fuel burn is now in the range if a tiny turboed gas engines .

An custom bell housing would need to be created to hang a marine tranny with a deeper reduction than the diesel.

The boat would be lighter quieter and with the low cost of maint compared to a diesel (and cheaper fuel) there should be no resale problems.

Yes a marine air cleaner , starter and alt would be required , as well as a bilge blower.


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Old 12-21-2017, 06:17 AM   #95
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For an example, this boat finished off at 5200 lbs without rigging, IIRC.

Trailer & Weight

You can look at the speeds and fuel consumption with the 60 hp.
Impressions

So pushing a hull that weighs just under 7 times the amount still leaves you with a "DOG" from the original setup.
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