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Old 01-04-2019, 12:00 PM   #1
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Jet Drive Trawler

Hi y'all! Southern boy here. I am a moderately experienced USCG 100GT master with a lifetime of small boat experience. Nearing retirement and want to fill my bucket list with last request. I have traveled East Coast US and experienced many boaters aground , mostly from lack of local knowledge and experience. I would like to explore a 48'ish pilothouse JET DRIVE dual diesel trawler. Is there any out there? Any used for sale? I have reviewed Bruce Roberts and he can engineer one. I want to do the Great Loop and be a liveaboard. Thanks for any input.
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Old 01-04-2019, 12:08 PM   #2
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Hi y'all! Southern boy here. I am a moderately experienced USCG 100GT master with a lifetime of small boat experience. Nearing retirement and want to fill my bucket list with last request. I have traveled East Coast US and experienced many boaters aground , mostly from lack of local knowledge and experience. I would like to explore a 48'ish pilothouse JET DRIVE dual diesel trawler. Is there any out there? Any used for sale? I have reviewed Bruce Roberts and he can engineer one. I want to do the Great Loop and be a liveaboard. Thanks for any input.
Jet drives are not typically economical so you will find them very limited in most trawlers.
The great loop will have you considering limits on draft, air draft, and tankage dependent upon what exact routes you might be planning.
Good luck - a great trip
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Old 01-04-2019, 01:30 PM   #3
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Have you looked around for a trawler with 'tunnel drives'?
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Old 01-04-2019, 02:16 PM   #4
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Yamaha makes jet outboards up to 150hp, why not look for a 48’ trawler with blown motors and spend a fortune converting it from diesel inboard to gas outboards? That’s about the only way I know of getting what you want without a new build.
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Old 01-04-2019, 02:37 PM   #5
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The economy, speed and performance characteristics of jets don't come close to what trawlers are all about. There's a reason you don't see any jet powered trawlers.
For your planned needs the tradeoffs won't add up no matter what calculator you use.

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Old 01-04-2019, 03:02 PM   #6
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We have a couple of 48' aluminum cats in our fleet. They are commercial tour boats but loaded with passengers the weight might be similar to a pleasure boat. Twin Cummins with Hamilton Jets, they run at about 25kn and burn about 40g/hr.
Fuel consumption, maintenance issues, and cost are all negatives compared to using a prop. The up sides for us are planing speed, beachability, and no chance of prop strikes for marine mammals, none of which would really apply to what most folks think of as a trawler.
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Old 01-04-2019, 03:35 PM   #7
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jet drive trawler

Thanks for the comments. I currently operate a 54' tour boat w/ capacity of 76 passengers. It has a single diesel hooked up to a traktor gear box and jet drive. It operates at 1200 rpm consuming 1.5 gph fuel. Now take in regards I only drive at 8 knots but that's roughly trawler speed. That is mounted on an aluminum hull. I want this kind of technology on a trawler which I envision as my camper.
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Old 01-04-2019, 03:52 PM   #8
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Thanks for the comments. I currently operate a 54' tour boat w/ capacity of 76 passengers. It has a single diesel hooked up to a traktor gear box and jet drive. It operates at 1200 rpm consuming 1.5 gph fuel. Now take in regards I only drive at 8 knots but that's roughly trawler speed. That is mounted on an aluminum hull. I want this kind of technology on a trawler which I envision as my camper.

I guess my questions would be: What are you getting with the jet drive beyond reduced efficiency? Is that important enough for a pleasure trawler, to offset the negatives?
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Old 01-04-2019, 04:03 PM   #9
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I have also delivered boats up and down the "ditch", the ICW and have witnessed numerous hard groundings which entail bent shafts, props, struts, etc. and weighing the inconvienence and huge cost of repairing those damages; that down time is frightening.
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Old 01-04-2019, 04:53 PM   #10
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Hi Mikey,
Having been up and down the ditch once, we feel you on the"excitement" of touching bottom. We never have but we've kicked up mud on a couple occasions. Quite a high pucker factor. A more realistic thing, and I know I've seen a couple but can't put my finger on one now, are outboard mounted trawlers. You could trim up in skinny water. And maybe, just maybe, those sweet diesel outboards will become more available some day.

I heard somewhere that jets are 30% less efficient than a straight prop. I've also heard that 52.7% of all statistics are made up.

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Old 01-04-2019, 05:03 PM   #11
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Thanks for the comments. I currently operate a 54' tour boat w/ capacity of 76 passengers. It has a single diesel hooked up to a traktor gear box and jet drive. It operates at 1200 rpm consuming 1.5 gph fuel. Now take in regards I only drive at 8 knots but that's roughly trawler speed. That is mounted on an aluminum hull. I want this kind of technology on a trawler which I envision as my camper.
This works out to 6.14 statute mpg. I find this hard to believe without more information about the boat and the conditions it operates under. Also what is the engine, make and hp?
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Old 01-04-2019, 06:48 PM   #12
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I have also delivered boats up and down the "ditch", the ICW and have witnessed numerous hard groundings which entail bent shafts, props, struts, etc. and weighing the inconvienence and huge cost of repairing those damages; that down time is frightening.
Seems to me a single engine,full keel boat and attention to navigation would be a much simpler solution.
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Old 01-04-2019, 08:16 PM   #13
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I travel up and down the ditch from Norfolk to Stuart twice a year. It's really not that difficult to avoid running aground. Single screw with full skeg under the prop makes it pretty bullet proof. If one checks the comments on Waterway guide and avoids traveling at low tide in skinny areas, it's not difficult to do the ditch with a 5' draft. Likely a substantially smaller investment that might be more beneficial would be forward looking sonar.

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Old 01-04-2019, 09:26 PM   #14
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When we traveled through the TSW in 2016 the weeds were so thick that we had to stop and back down to clear the props about every 100 yards in Canal Lake. The day before we went through a boat actually got so bound up it had to be towed. It was bad enough with inboard props but how bad would it be to suck all those weeds into the jet drive?
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Old 01-05-2019, 03:08 AM   #15
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I love Jet Drives but the concept doesn't find itself connected to Trawlers very often. Mikey refers to a unique system and special application. The nearest that I'm aware of to a Jet Trawler would really be more a Jet Cruiser and the most popular US builder in that arena is Hinckley. They use Hamilton Jets and cruise as fast as in the 30's. Could definitely be run at Trawler speed and get decent economy and range. Their Picnic boats come with smaller engines and their Talaria models come with larger engines.

The comment on weeds, but the poster had issues with props and most places that would have problems with weeds and jets would also with props.

There would be some sacrifice on economy but a great offset with performance and speed and the economy sacrifice at trawler speed would be modest, it's at greater speeds that the fuel cost would increase.

If there was a jet in the size and design we want for the loop, I would absolutely give it strong consideration.
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Old 01-05-2019, 04:18 AM   #16
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I travel up and down the ditch from Norfolk to Stuart twice a year. It's really not that difficult to avoid running aground. Single screw with full skeg under the prop makes it pretty bullet proof. If one checks the comments on Waterway guide and avoids traveling at low tide in skinny areas, it's not difficult to do the ditch with a 5' draft. Likely a substantially smaller investment that might be more beneficial would be forward looking sonar.

Ted
Ted,

Find me a forward sonar that works. (probably good for another thread)
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Old 01-05-2019, 08:57 AM   #17
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A full skeg would definitely be the answer, dependability of forward sonar has been brought up, are they less than 100% reliable and what are their issues?
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Old 01-05-2019, 09:47 AM   #18
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I have forward looking sonar and do not find it to be any more useful than bottom looking. Unless you are in deep water approaching a wall, you will be in shallow water where the forward range is less and it is easy to overrun your sonar. We run much of the time at 10mph and unless I was watching the forwards depth finder at all times I would be on the shallow before I could stop: 50 tons has a fair amount of momentum! On plane at 20mph it would be impossible. There are also several spurious readings in any given 10 minute period which would have you slamming the gears into reverse if you heeded every warning. And if you don’t do so, how will you know the difference between a real shallow or a false one?
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Old 01-05-2019, 10:34 AM   #19
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economy will be poor on a jet drive - these are a few of the articles available for research...

Direct comparison...
https://www.boatingmag.com/boat-engine-comparison
Larger applications...
https://www.boatdesign.net/threads/j...iciency.19655/
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Old 01-05-2019, 06:26 PM   #20
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Forward looking sonar seems to work well at slow speeds. The issue is going slow enough that you can stop in time. It's not going to help you at 7 knots on the AICW. If you're going 7 knots where you think you might run aground....

Ted
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