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-   -   Swift Trawlwer 34 range (https://www.trawlerforum.com/forums/s60/swift-trawlwer-34-range-51720.html)

Portage_Bay 07-02-2020 07:08 AM

Swift Trawlwer 34 range
 
I'm looking for information on the range of the 34. With a 425 HP Cummins and 211 gallons of fuel tank I'm sure the range is very limited and the boat will need to be run at the lower end to cover any distance. I would very much appreciate experienced input for best range. Engine RPM, GPH burn and speed.

rslifkin 07-02-2020 07:24 AM

Pretty much any planing boat above 25 - 28 feet will pay a significant range penalty up on plane. I found a test online of a 2010 model. Looks like 7 kts (1000 RPM) gives 1.3 gph / 5.42 nmpg, which seems a bit better than I'd expect. 15 kts is 12.7 gph / 1.18 nmpg, so definitely much less range.

Portage_Bay 07-02-2020 07:33 AM

Thank you for the quick reply. Yes, I'm aware speed comes at a cost.


Do you have a link to the study you found? My digging around the internet didn't turn up anything useful.

rslifkin 07-02-2020 07:45 AM

Quote:

Originally Posted by Portage_Bay (Post 895209)
Do you have a link to the study you found? My digging around the internet didn't turn up anything useful.


https://www.powerandmotoryacht.com/b...ift-trawler-34

Portage_Bay 07-02-2020 08:01 AM

Very good link, thank you. I've also found this test



https://www.boattest.com/review/bene...wler-34https://

ScottC 07-02-2020 08:05 AM

Also interesting....
(scroll to bottom...)
https://www.boatingmag.com/boats/ben...ft-trawler-34/

DavidM 07-02-2020 08:14 AM

I had a similar boat to the ST34, the Mainship 34T. That boat burned 3 gph at 7.5 kts. So applying that number to your boat and keeping a 20% reserve, it will go for 56 hours and travel 420 NM on a tank of fuel.

At 12 kts it would burn about 11 gph, so it would go for 15 hours and travel 180 NM.

Your numbers should be very close.

David

Portage_Bay 07-02-2020 09:57 AM

Thank you all for your input and assistance. The data varies a bit from site to site but I have what I need.

MYTraveler 07-02-2020 12:26 PM

Quote:

Originally Posted by Portage_Bay (Post 895248)
Thank you all for your input and assistance. The data varies a bit from site to site but I have what I need.

FWIW, IME, the fuel consumption numbers published in new boat reviews are not real world numbers -- they reflect a new boat with a pristine bottom and well tuned props, and a boat that doesn't have the added weight of a typical owner's possessions aboard.

Portage_Bay 07-02-2020 01:17 PM

Quote:

Originally Posted by MYTraveler (Post 895296)
FWIW, IME, the fuel consumption numbers published in new boat reviews are not real world numbers -- they reflect a new boat with a pristine bottom and well tuned props, and a boat that doesn't have the added weight of a typical owner's possessions aboard.


Agreed. But I need something to get started with rough estimates as I am not familiar with this boat.

Danzan33 07-06-2020 01:55 PM

I have a ST 34. At planning speeds, about 13 to 20 knots we normally get about 1 to 1.1 NM per gal. When we were fully loaded with fuel, water and stuff for the loop, we were only getting .9 to 1 NM per gallon at planning speed. if we slowed down to about 6 to 6.5 Kt we get about 3.5 NM per gallon and sometimes up to 4 NM per gallon depending a lot on wind and current. Slower than that and we got even better NM per gallon. But between about 8 knots and planning speed, mileage is only about .8 or .9 NM per gallon since it feels like we are just digging in.

SOJOURN4 07-07-2020 07:52 PM

On our ST34, we averaged 1 nm/gal as noted by Danzan33
Good luck

Portage_Bay 07-07-2020 08:31 PM

Thank you all for the replies, very helpful. I've made the trip, by running at moderate speeds until the end we covered 336 nm on about 105 gal.

markpierce 07-07-2020 08:36 PM

How does that compare with your California 42?

Portage_Bay 07-07-2020 09:57 PM

The ST is much easier on fuel. I haven't run the Californian long enough to have good fuel numbers for her. The Californian is the boat I want for comfort and all the things that make boating a pleasure for me.


Quote:

Originally Posted by markpierce (Post 897447)
How does that compare with your California 42?


Portage_Bay 07-08-2020 08:56 AM

Mark,

A more complete answer after giving it some thought. Keeping in mind that I don't have a lot of underway time on either boat so I'm going with published numbers on GPH and observed speeds. Much of the limited time on both boats was in strong currents so observed speeds have been corrected as best I can without having run courses in opposite directions to average speed. Both boats have clean bottoms and running gear.

Beneteau ST 34
Single Cummins QSB5.9I
RPM - Knots - GPH - nMPG
1000 - 5.5 - 1.25 - 4.40
1500 - 7.5 - 2.9 - 2.59
2500 - 15 - 12 - 1.25


The published data for the ST are from:
https://www.boattest.com/review/bene...ift-trawler-34
https://www.powerandmotoryacht.com/b...ift-trawler-34
https://www.boatingmag.com/boats/ben...ft-trawler-34/

I did not observe the performance the tests found so take my data for what it's worth. Still the ST is a very fuel efficient boat. In part due to her small size, light weight and ability to plane.

Californian 42 LRC
Twin Cat 3208 naturals
RPM - Knots - GPH - nMPG
1000 - 4.5 - Unknown
1400 - 6.5 - 3.8 - 1.71
1600 - 7.5 - 4.8 - 1.56

The fuel burn #s are from Cat data sheets found on boatdiesel.com. The data start at 1500 at 2 GPH so I've guessed 1400 is 1.9. She's a twin so I doubled the GPM from the Cat data sheet. An argument can be made that you don't have to double the #s, but until I have more time / distance on her it's all I can do.

This shows with limited experience the ST is far easier on fuel than the Californian.

Beyond fuel consumption for my needs and wants there is no comparison. The ST is small and to me feels cramped. Interior trim is all laminate which I do not find attractive. Tankage especially potable water and black water are limiting factors for the way I want to use a boat.

So all things considered I'm happy with the Californian. And for the price difference of $330K for the ST vs $70K I purchased the Californian for I can buy a lot of fuel to support my comfort.

But if speed is your thing the ST is reputed to make 20 kts top end burning about 20 GPH. Pretty darned good! Wind the 3208's in the Californain up and on pre purchase sea trials we saw 12 knots and I'd expect her to burn about 20 to 25 GPH. I wouldn't want to do that for very long.

rslifkin 07-08-2020 08:59 AM

Those fuel burn numbers for the Californian seem a bit high to me. Not crazy high, but unless the 3208s have particularly bad light load efficiency, they're higher than I'd expect. I would have figured more like 3 gph total at 6.5 kts.

Portage_Bay 07-08-2020 11:19 AM

Quote:

Originally Posted by rslifkin (Post 897583)
Those fuel burn numbers for the Californian seem a bit high to me. Not crazy high, but unless the 3208s have particularly bad light load efficiency, they're higher than I'd expect. I would have figured more like 3 gph total at 6.5 kts.


I think you're correct and I expect the #s to be better to be determined after I've got some time and distance on her.

4fun1 07-08-2020 03:54 PM

Quote:

Originally Posted by Danzan33 (Post 896811)
I have a ST 34. At planning speeds, about 13 to 20 knots we normally get about 1 to 1.1 NM per gal. When we were fully loaded with fuel, water and stuff for the loop, we were only getting .9 to 1 NM per gallon at planning speed. if we slowed down to about 6 to 6.5 Kt we get about 3.5 NM per gallon and sometimes up to 4 NM per gallon depending a lot on wind and current. Slower than that and we got even better NM per gallon. But between about 8 knots and planning speed, mileage is only about .8 or .9 NM per gallon since it feels like we are just digging in.

I also have a ST34 and get the same.

Tigs 07-17-2020 02:47 PM

I have a ST34 and I find the fuel consumption great at trawler speed. The added benefit is the possibility of going 20knots to get out of bad weather for instance. I think the comparison though should of been between a swift 44 (dual engines) vs the Californian 42 LRC


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