Outboard trawlers

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Good points. By my eyeball, looking at shear line and the rest of the boat, she lies pretty straight (level). Wonder what's in the engine room. About 800# each (dry) cantilevered out a couple of feet. I'll be in GPT for a couple of weeks - I'll try to catch up with the owner.
 
The weight and balance might be a wash depending on the original engines and tanks. A pair of diesels and marine gearboxes are not light, even gassers, it just depends on where the weight was removed. Remember that they probably pulled the shafts and rudders along with the old props and that is all as far aft as you can get and still be inside the hull. If there was a center.ine tank in the stern the improved fuel economy might let you keep it empty which would help too.
 
Benthic2 said:
Did you notice if it steered with the ouboards or the original rudder(s) ?
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It would need to the be by the outboards. The rudders would be in front of the prop thrust and have very little effect. I suspect they removed the props, shafts, and struts to reduce drag.

Must be a massive storage locker in the old engine compartment. We call our guest cabin the 'walk-in closet'. I'd bet before long, we'd be calling the old engine compartment the 'basement'.
 
Mercruiser 350's are about 900 lbs each. Yamaha 200's are about 500 lbs each for a savings of 800 pounds.

Getting rid of the transmission, rudders, shafts, thru hulls, logs and props probably saves another 500-600 pounds.

A lot to like with a 1300-1400 pound haircut.
 
sbu22 said:
That worked well - again:
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What kind of boat - Pacemaker? Uniflite?

Swim step is really low to water... wonder if that is because of engine removal weight and cantilevered weight of o/b's? Maybe they did raise boot stripe to make things look correct.

Big-Problem for me and wife would be no more use of swim platform for swimming and loading onto or out of our tow behind runabout. Unless there were great handling advantage and way less fuel usage I'd pick the inboards.

O/b's would basically be in my way too much for other items of fun. also, back into a pier and see how much that costs - :facepalm::facepalm::facepalm:
 
From my look, that's not so much a "swim step" as a cover for the substantial structure under it. You can't see it well in the pic, but the vertical white engine attachment point is the end of a complex structural shape that, I imagine, extends well forward under the hull for attachment.

At roughly $30k buy per engine, plus inboard engine and running gear removal, structural mods, installation - looks like a $100k in it. Assuming gas V8s were original, he could have installed Jasper rebuilds and reworked the trannies for 20% of the cost.
 
Lots of outboards are run on Armstrong brackets and the setback allows for a useable swim step/boarding platform although you have to access from either side and not from directly astern.

The Op said there were 700hp and that implies 350's and not 200's which are probably heavier, then again it may have had big blocks instead of small blocks if they were gassers.
 
sbu22 said:
From my look, that's not so much a "swim step" as a cover for the substantial structure under it. You can't see it well in the pic, but the vertical white engine attachment point is the end of a complex structural shape that, I imagine, extends well forward under the hull for attachment.

At roughly $30k buy per engine, plus inbmoard engine and running gear removal, structural mods, installation - looks like a $100k in it. Assuming gas V8s were original, he could have installed Jasper rebuilds and reworked the trannies for 20% of the cost.
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I am not sure I see $40k in structural and rigging work there, but I agree that it is nearly always cheaper to rebuild than repower....... Removing the engines and all the running gear and rudders while not a small task could be performed by a motivated and reasonably skilled owner themselves which could lower the bill significantly.
 
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Art said:
What kind of boat - Pacemaker? Uniflite?

Swim step is really low to water... wonder if that is because of engine removal weight and cantilevered weight of o/b's? Maybe they did raise boot stripe to make things look correct.

Big-Problem for me and wife would be no more use of swim platform for swimming and loading onto or out of our tow behind runabout. Unless there were great handling advantage and way less fuel usage I'd pick the inboards.
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My thought is that is not the original swim step but a purpose built platform to mount the engines.


Another ignorant outboard question since I've never owned a boat with large outboards.... If you need those motors serviced, how do you do it? That is not a boat you throw on a trailer and take to a shop. 500-900 pounds per motor isn't something that you pick up and carry to your pickup. Do mechanics make house calls for outboard motors?


What about those of you that have tow-behind tenders that have 40+hp motors? Unless you trailer your tender, how to you get your motors worked on?
 
One nice thing about outboard trawlers is, easier to repower.
 
dhays said:
My thought is that is not the original swim step but a purpose built platform to mount the engines.


Another ignorant outboard question since I've never owned a boat with large outboards.... If you need those motors serviced, how do you do it? That is not a boat you throw on a trailer and take to a shop. 500-900 pounds per motor isn't something that you pick up and carry to your pickup. Do mechanics make house calls for outboard motors?


What about those of you that have tow-behind tenders that have 40+hp motors? Unless you trailer your tender, how to you get your motors worked on?
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You get service just like any other boat. You take it to the yard. Just many more outboard experts available because there are so many more outboards than inboards. You don't haul your boat on a trailer for service.
 
BandB said:
You get service just like any other boat. You take it to the yard. Just many more outboard experts available because there are so many more outboards than inboards. You don't haul your boat on a trailer for service.
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Thanks. Always kind of wondered. It seems up here that if you have a boat with an outboard, you also have committed to a trailer (and finding a place to store it) as well as a vehicle large enough to tow it.
 
Continuing along the "service" aspect. Couple o' glitches I foresee...


1. Standing on the platform you could get to front and at least 2/3rd back on sides of engines... but for rear of sides' 1/3 and back of engine - use a boat I guess. Maybe pull so close to floating dock that engines nearly touch. If so better hope not too much wake disturbance for either technique. Little chance for sitting on a firmly placed stool to perform operations.
2. Woops... I dropped the starter, or wrench, or compression gauge, or you name it. Good thing there's only about 10' water here. Hope it did not sink in the silt/mud!
3. Does the o/b lift high enough to be out of the water when docked? If not - we all know what happens to aluminum o/b housing!
4. LOA. Seems that with o/b's lifted out of water and their big size creating extra length the LOA of a boat could increase by several feet. Especially if long shafts were needed to get prop low enough in the water to be below boat's bottom - if that's necessary??!! Whole new set of rules [physics] regarding water turbulences, cavitation, water flow, reverse prop engagement by the smaller props. How big will the props be able to become on o/b's... I have no idea. Can they be big props geared down to turn slow compared to engine's power-packs rpm?


How heavy cantilevered off the rear will diesel o/b's with let's say 200 hp ea. need to be?


What happens in a really "pushy" following sea??


If drift wood gets run over... what's the outcome? Are o/b's likely to not only get prop damage but maybe entire lower unit too.


On a good note. Can trim up the engines for gunk holing without props getting into bottom contact.


Just wondering!
 
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I spent some time with an owner of a commercial boat converted from diesel inboards to outboards. He had a pod added to the transom that easily provided the bouyancy to carry the outboards. Hard to tell in the pic but there could be a pod hiding under the platform.

Then the ex-engine room became useful storage space. Extra fresh water tankage, a bigger holding tank.
 
I can't answer all those questions, but the industry seems to have figured it out. Intrepid, Grady White, Hydrasports and others are all putting out 40 - 50 foot boats with quad outboards on them. The Hydrasports 53 footer has over 4,000 pounds of engines hanging off the back. ( and the price starts at $1.7 million )
 
On the plus side, there is no failure mode of an O/B that will sink your boat due to the failure of some component in the motor or drive.

A number of motor brackets (e.g. Armstrong) and actually hollow assemblies that add buoyancy to the stern of the boat.

Usually the way an O/B is mounted, the increase in LOA is not as much as you might think with the motors up vs. down because of where the pivot point is.

Even if you hit something and damage the O/B lower unit. It can be replaced pretty quickly and for a few hundred $ (depending on engine size). Takes about 20 minutes. Some installations allow the O/B to tilt up if it hits something heavy which can eliminate or mitigate the damage to the lower unit.

If you have an inboard and hit something, you may damage the prop, the prop shaft, the strut(s), and the through bearings. You could end up with a substantial leak. You'll also need a haul out to do the repairs or maybe even just to assess the damage.

There are plenty of O/B powered boats that don't have trailers. Even smaller sized boats.
 
ssobol said:
On the plus side, there is no failure mode of an O/B that will sink your boat due to the failure of some component in the motor or drive.

A number of motor brackets (e.g. Armstrong) and actually hollow assemblies that add buoyancy to the stern of the boat.

Usually the way an O/B is mounted, the increase in LOA is not as much as you might think with the motors up vs. down because of where the pivot point is.

Even if you hit something and damage the O/B lower unit. It can be replaced pretty quickly and for a few hundred $ (depending on engine size). Takes about 20 minutes. Some installations allow the O/B to tilt up if it hits something heavy which can eliminate or mitigate the damage to the lower unit.

If you have an inboard and hit something, you may damage the prop, the prop shaft, the strut(s), and the through bearings. You could end up with a substantial leak. You'll also need a haul out to do the repairs or maybe even just to assess the damage.

There are plenty of O/B powered boats that don't have trailers. Even smaller sized boats.
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I'm not saying that o/b's are not at all plausible... cause they are. I just like to point out short falls of new items as they come to market regarding full sized boats [i.e. not runabouts].

Plenty of short falls also exist about inboards... those items have been exhaustively hashed over for about a century!

So... here is another short fall about huge, heavy outboards on boats too large to be easily trailered into a dry, heated engine repair shop.

The good ol' rainy day or snowy day maintenance and repair schedules will be greatly diminished, maybe even completely unavailable. Unless boat and o/b's may be in covered slip. And, if it's below "0" +/- temperature outside... well... So that means that most likely sunny, warm days [the ones you'd rather be out and about on the water] will be used for what poor weather on other days previously enabled.

Just pointing out what I see as potential downfalls to heavy boats with huge heavy [and, quite expensive] o/b's hanging off their stern.
 
Art said:
....... I just like to point out short falls of new items as they come to market regarding full sized boats.....
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Nothing about outboard powered boats is new. Grady has been making boats over 30 feet for 25 years ( or more )...I'm sure many others have as well.

In 1992 I worked on a 45 foot outboard powered boat.

There's only so much room on a transom, so when the biggest outboards were in the 200 horsepower range, that limted the size of boat you could put them on. Now that outboards are pushing out 350-600 hp you can power larger boats with them. Back in the day horsepower was the limiting factor, not boat size....as output grows, boat size applications will too.
 
Benthic2 said:
Nothing about outboard powered boats is new. Grady has been making boats over 30 feet for 25 years ( or more )...I'm sure many others have as well.

In 1992 I worked on a 45 foot outboard powered boat.

There's only so much room on a transom, so when the biggest outboards were in the 200 horsepower range, that limted the size of boat you could put them on. Now that outboards are pushing out 350-600 hp you can power larger boats with them. Back in the day horsepower was the limiting factor, not boat size....as output grows, boat size applications will too.
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Undoubtedly!
 
Imagine of what will happen if I remove my twin Lehman 80hp and trans. I will have to replace the weight with led or concrete to keep some form of stability. Diesel outboard are expensive as hell and hard to find. I will NOT have gasoline on my boat.
 
nodestination said:
Imagine of what will happen if I remove my twin Lehman 80hp and trans. I will have to replace the weight with led or concrete to keep some form of stability. Diesel outboard are expensive as hell and hard to find. I will NOT have gasoline on my boat.
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Yes, remove the inboards and transmission, you can renovate the ER and call it the "Mother in-law suite".
 
You all talking of putting the outboard on transom or swimming platform, but there is another way use a lot by a sailboats - the well box. The advantage of an O/B is cost of maintenance, eliminate potential "sinking" cause of a trough hulls,shafts(packing). No more crawling in tight spaces ( painful in my age), internal noise reduction. The cons are the fuel efficiency as the outboards come with 3 times smaller props. The bigger the prop the less "water slip". BTW, I do not have 600lbs mother in law to compensate for the weight loss in center.
 
nodestination said:
You all talking of putting the outboard on transom or swimming platform, but there is another way use a lot by a sailboats - the well box. The advantage of an O/B is cost of maintenance, eliminate potential "sinking" cause of a trough hulls,shafts(packing). No more crawling in tight spaces ( painful in my age), internal noise reduction. The cons are the fuel efficiency as the outboards come with 3 times smaller props. The bigger the prop the less "water slip". BTW, I do not have 600lbs mother in law to compensate for the weight loss in center.
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I'll lend you one!
 
Art - no idea the manufacturer - she looks late 70s - early to mid 80s based on style. The pic doesn't show it, but the lower units are clear of the water by about a foot when raised. Looks like garden variety props for an engine that size - not "wheels".

As to stern protection, I see a lot of the myriad water cop agencies down here, all with 30+ foot CCs with quad high power outboards (other people's money), have nerf bars that extend from the support platform to protect the engines from side/stern damage.
 
BandB said:
Seems to me that if I take a 36-50' boat and I hang 1, 2, or 3 outboards on the back instead of an inboard engine, that I've picked up a lot of internal space, I have reduced my draft problems, I have reduced repair costs and challenges. I'm not talking Nordhavn or KK replacements, but I'm certainly talking the typical person here doing coastal cruising and those taking the loop.

Have given this some thought. By hanging outboards beyond the transom you are lengthening the distance to the fulcrum point. Thereby giving the outboards a mechanical advantage to pull your stern down. In a planing hull this does not make a difference when on plane. For displacement hulls would this be an issue?

Heck, just saw mine is the 180th response. Sorry if this has been addressed already.
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