Overpowered Trawler???

The usual rule of thumb is to divide the actual displacement by 2240 for the boats displacement in tons.

The tones times 2hp will be close to the Hp required at LRC SL 1 or so .

Tons times 3hp is for inshore where fuel is easy to purchase .

Tonnes times 5 is about the max rating the engine would have on a 24/7 basis , tho lower is acceptable to operate the engine more efficiently.

Happily the monster motors will probably have a large diameter prop.

So you could install a 5 or 6-1 reduction on the new small engines , and perhaps go to a 2 blade prop set for higher efficiency .

For the most efficient LRC you might be using one engine and locking the 2 blade prop to better load the operating engine.



FF

 

Fred: Mr. Neville, the designer, said similar. He alternating engines on a run, and suggested, if the boat worked well with one engine, then we might look at getting adjustable feathering prop! We will see how long it sits for 200K.
Aliboy: I agree with you, too much fuel. Not sure why!

 

If you want to pay 100K (or whatever) best make an offer for that with a proviso for a survey and a sea trial, and see what happens. Better then waiting and maybe later hear someone has bought her for a price you also was willing to pay. Give the bid a time limit (say you need that because if rejected you want to be free for a bid on another boat) so they don't peddle around with your bid for someone to just top it with 1K while you're waiting. When accepted have a written option for that price from the US broker and US owner before making any costs. Make sure your bid can go down if the survey or sea trail brings unexpected costs to light or the deal can blown off at all for that or for not behaving or consuming as can be expected from the sales data¹. BTW, some pics are dated 2009, if neglected since the boat could be in a different state now, and some pics are dated 2013 which can't be correct. Best ask for a good set of recent high resolution pics before doing a bid.

1. Excerpt from the sales data:
   
   ‘‘ She is an extremely sea capable boat that has a very low fuel burn rate at cruise speed. ’’
   ‘‘ Cruising Speed: 9 knots ’’
   ‘‘ Maximum Speed: 12 knots ’’
   ‘‘ Range: 1000 nm ’’
   -- at what speed and with what reserve and in what conditions is that given range according to the seller ? --
   ‘‘ Fuel Tanks: (1000 Gallons) ’’
   ‘‘ She has been maintained by an experienced yachtsman and is in TURN KEY condition. ’’

You bid for what they say she is, if it appears otherwise upon inspection than renegotiate or withdraw the bid, this saves you the trip if an agreement can't be reached in the first place.

Good luck !
Angel

 

The 2009 and '2013' dated pics looks like special purpose made for the sale as they don't show any people at all. The few bits of skyline in the pics looks as the port where they claim she is now.

The interior pics don't show anything of this sales claim: ‘‘Interior Refit, Refinished, Updated (2012)’’

She might be for sale for years now, and this was done after the pics were taken . . . . ? ?

Ah, there's the answer to my last above question in gray, so no reserve in the given range at their given cruising speed, and in smooth conditions I guess . . .

Good luck !
Angel

 

Angel, We are stuck somewhat and have to wait, as we will be paying cash and that we will get for the sale of property which is set to in the middle of Aug. So we must wait. And, the broker confirmed the 1mpg with the broker, but apparently they thought that was excellent and never tried her at 6 or even 8kts. Problem is the engines would be just above idle at 7. I am trying to find out how long it has been on the market. I found it 2 months ago and i have worked hard for about a year finding boats and knowing what is for sale. Could have missed it, or it could have been for sale, then off the net, now back on. We will be buying a boat this fall, but have 2 kids to get through college. May end up with a lessor boat and be putting together a larger pot and find a true displacement boat to build up or refit. We will spend a lot of time on her, and end up living aboard and really want something very seaworthy. Patiently trying to be patient and smart. Thanks for the input. Very useful!!! rj

 

Consider this, to bring her home you'll burn about 2,100 Gallons* at 9 knots, a bit less at 7. If this kind of usage or even half of it + the maintenance is a concern then buy smaller, otherwise you can't use the boat much.

* Via the shortest route, but max safe range with 20% reserve is 800 Nm in her current 9 knots cruising speed condition, which isn't a Long Range Trawler but an Island hopper. This boat can hardly go your shortest route home from south west Cuba, Puerto de Nueva Gerona, to Mobile.

Good luck !
Angel

 

With an American owner/boat-a bit of a problem there...

 

So the route will be longer and he'll burn more . .

Cheers,
Angel

 

No worries..it's in Colombia IIRC, so he can throw on some fuel bladders,swing by Venezuela and fuel up for 3 cents a litre

 

Colombia Carib coast is correct, but if he goes departure will be closer to Panama, so Venezuela drives him far east first, and then he'll ‘nearly sink’ the boat to carry the fuel to bring him home . .

Cheers,
Angel

 

Lots of things don't quite add up with this. If you are at 7knts just above idle (say ~900 rpm?) then those engines should be at say 1200rpm - 1300rpm at
8knts or so? Maybe 1400rpm at 9knts? If they are at these rpms at those speeds then I doubt that they are running within the design parameters for those engines when burning that much fuel. Find out what rpm's they are using for 9knts and check the fuel use graphs for those engines. Doesn't sound to good too me.

 

I will check! Right now i am on vacation and internet is sparse.

 

Best also ask for the props and transmissions specs to see...

1) If everything is consistent with each other or where a mismatch, besides the engines size vs the boat, might be.

2) What you can reuse in a different set up.

Cheers,
Angel

 

For fuel consumption comparison + info what usage can be achieved at lower speeds on a compared boat of similar dimensions and displacement . . . .

Below are quotes, I've added some remarks in gray.

---------------------------------------------------------------------------------

The for sale boat at issue on this thread:

Dimensions
LOA: 55 ft 0 in
Beam: 17 ft 0 in
LWL: 51 ft 0 in
Maximum Draft: 4 ft 6 in
Displacement: 90000 lbs

Engines
Engine Brand: 2 x Lugger
Engine(s) Total Power: 870 HP
Engine Model: 6125A
Engine Type: Inboard
Drive Type: Direct Drive
Cruising Speed: 9 knots
Maximum Speed: 12 knots
Range: 1000 nm ~ @ 9 knots and no reserve
Usage: @ 9 knots ~ 1 NM/gal.
Year Built: 1991

Tanks
Fresh Water Tanks: (500 Gallons)
Fuel Tanks: (1000 Gallons)
Holding Tanks: (300 Gallons)

---------------------------------------------------------------------------------

For comparison a boat of similar dimensions and displacement:

Krogen 55' Expedition - (use links left of the pic for more info)

Brief Specifications
Length Overall (LOA including swim platform & pulpit) 60'-11 3/4"
Length on Deck (LOD) 55'-2"
Length at Waterline (LWL) 49'-6"
Beam (Over Rub Rail) 18'-0"
Draft at Keel (half load) 4'10"
Displacement (half load) 87,870 lb. approx.
Ballast (Encapsulated Lead) 6,900 lb.
Fuel 1880 gal.
Water 500 gal.
Black Water Capacity 140 gal.
Gray Water Capacity 140 gal.

Approximate Bridge Clearance
With mast up: 24' 1"
With mast down: 20' 11"

Range & Usage
7 knots: 4,300 Nautical Miles / (1,880 gal. x 0.9) = 2.54 NM/gal.
8 knots: 2,800 Nautical Miles / (1,880 gal. x 0.9) = 1.65 NM/gal.
9 knots: 1,850 Nautical Miles / (1,880 gal. x 0.9) = 1.09 NM/gal.
10 knots 1,200 Nautical Miles / (1,880 gal. x 0.9) = 0.71 NM/gal.
NOTE: Calculated with a 10% reserve. Ranges are approximate.

Twin Engines: (2) Tier II John Deere^®, #6068TFM75, Each 158 bhp @ 2400 rpm with Twin Disc^® 2.88:1 ratio gears

Twin Shafts: (2) Aquamet^® 22, 2" diameter

Twin Propellers: (2) Hung Shen, bronze, 5-bladed, 31"diameter x 19" pitch

Specifications and equipment are accurate at time of posting, however, are subject to change.

---------------------------------------------------------------------------------

BTW, 1 NM/gal. @ 9kts. for the two big Luggers from 1991* in the for sale boat does look quite normal in this comparison.

* might function as new but is 21 years old technology which is compared to todays here

Good luck !
Angel

 

See also the Krogen 58' (use links left of the pic for more info) specs + range info from which usage can be calculated.

This one is available with single or twin engine & prop setup. Only one range/usage table is given, guess that's for the 1,810 gal. tankage of the standard single screw version. Usage of the single vs twin set up might not differ much, comments on this please, or ask Krogen.

Note: the twin set up in the 58' is the same as in the above 55', only the props differ . . .

---------------------------------------------------------------------------------

Krogen 58' propulsion:

Engines:
(1) John Deere^® 6090SFM75, 325 bhp @ 2100 rpm with ZF Marine^® 2.91:1 ratio gears.
Or Twin Screw Option:
(2) Tier II John Deere^®, #6068TFM75, 158 bhp @ 2400 rpm with Twin Disc^® 2.88:1 ratio gears.

Shaft:
(1) Aquamet^® 22, 2-3/4" diameter.
Or Twin Screw Option:
(2) Aquamet^® 22, 2" diameter.

Propeller:
(1) bronze, 4-bladed, 38" diameter, 26" pitch.
Or Twin Screw Option:
(2) bronze, 4-bladed, 32" diameter, 20" pitch.

---------------------------------------------------------------------------------

And the 58' Krogen also had the option of a single Lugger of the same type of which our topic boat has two.

Engine: Lugger^® 6125A, 325 bhp* @ 2100 rpm with Twin Disc^® w/2.95:1 ratio gear.
Shaft: (1) Aquamet^® 22, 2-3/4" diameter.
Propeller: HyTorq^® (1) bronze, 3-bladed, 38" diameter, 28" pitch.

---------------------------------------------------------------------------------

* The sales data of our topic boat says 435 HP each for those 6125A Luggers, but that might be short usage peak power, or they have a completely different engine tuning with shorter life span expectancy, or some info is wrong . . . . ? ? ?

Good luck !
Angel