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Old 09-20-2010, 03:03 PM   #1
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Basic Trawler questions

Greetings boating experts!

I am a lifetime sailor but this summer my family chartered a 40' trawler for a week, traveled 250 miles, and absolutely loved it. *It was this exact boat, fwiw:


http://www.yachtworld.com/boats/2004...-Cabin-2003884


While our charter experience has given me the bug/itch/whatever-you-call-it, the*likelihood*of actually buying a trawler is slim but I do enjoy browsing the classifieds and have some questions if you will have the patience to help educate me:


1. *This particular vessel has a single 220 Cummins and one of the shocks for me was fuel efficiency. *We only burned on the order of 100 gallons and that was running the generator most of the time. *I was expecting much worse over 250 miles and 6 days. *In fact I still wonder if they somehow accidentally under-filled it upon returning although that seems unlikely and I'm sure not going to inquire. *Now I did generally run on the slower end of stated cruising speed and worked pretty hard to find the "sweet spot" each day based on tides/winds - which generally was somewhere in the 1600 to 1700 rpm and 8 knot range. *I never went over 2000 at all and never cruised higher than 1800. *Remember I come from sailing - 8 knots is fine with me. * *So finally my question (remember I thanked you in advance for your patience): *Is this typical efficiency for a single screw?


2. How different is fuel efficiency for a*similarly sized*2-engine boat than this single screw? *Say a 40' marine trader for example. *Is it much worse? *Slightly worse? *Somehow (I dream) about the same?


3. I see in some classified boat pictures a picture of some structure on the forward deck that is usually centered right in front of the front windows - it's about 6" to 12" tall and a flatish A-Frame such that if you're standing on the bow pulpit looking back, it looks like a flat A-frame house - only it's about 8" tall and maybe 20" x 20" base. *It is sometimes covered with a protective canvas. *What is this? *A/C possibly?


4. I saw in one boat picture a large bag (looks about like a sail bag to me - big enough for a working jib or small genoa) from which a rope comes out of the tied up end that is tied off to the rear fly bridge stanchions. *What is this likely to be? *Some kind of emergency inflatable vessel? *It is not a dinghy I know that for sure. *Bag is probably 3' high by 18" diameter with the open end on top.


5. This trawler we chartered had nice c-shaped dinghy mounting things (ha) that flipped up/down on the swim platform making it very convenient to pull it out and store it vertically on the swim platform. *Great, but we fish and swim a lot and need that space for something other than dinghy toting. *I see some boats for sale that show a dinghy living on the rear deck. *Presumably, there is some hoisting system they use with the mast/boom for this arrangement? *Is that typically a manual system or a power winch type? *And either way, is it easy or cumbersome compared to what we had - the two swinging C-clip things for dinghy on the swim platform? *Assume an avon-type inflatable dinghy.


Thanks so much in advance for any guidance! *I have to say I've been dreaming about trawlers since our trip. *I hope winter gets here soon to distract me. *A ski trip should do it - I think I can hold out.
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Old 09-20-2010, 05:26 PM   #2
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RE: Basic Trawler questions

My what interesting questions!* I just bought a trawler a couple of weeks ago after years of sailing and can't answer most of your questions but I look forward to seeing the replies.*

I believe the answer to # 3 is a dog house hatch.*

# 5 the hoists I generally see are manual though I have seen some power ones.* The sound of the guy across the dock from my running his power one Sunday morning brought me up on deck to see who was making that gawd awful racket.

I wonder if #4 is a whole lotta line?* Maybe they are somewhere with tall locks that they need a lot of line for?* that is PURE speculation on my part.* One of our friends has a HUGE spindle of line mounted (somewhere, I forget exactly where) on his boat for tying up to moorings or what not.

ok I am ready to read others anwers...* I feel like this is a trivia game.
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Old 09-20-2010, 06:23 PM   #3
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RE: Basic Trawler questions

Scott,

I run a 34' trawler with a 120 Lehman, and I burn about 2 1/2 gph at 1700 rpm, which normally equates to about 8 knots. *This means, under good conditions, that I'm getting about 3.6 miles for every gallon burned.


The newer engine you were using is undoubtedly more efficient than mine, and with a heavier boat, it seems you got about 2.5 miles for every gallon burned. When you factor in the genset, you actually got better mileage than even 2.5!


1.*Is this typical efficiency for a single screw? *In my estimation, yes. *Trawlers are very fuel efficient; hence many of we 'ex-sailors' love them.


2. How different is fuel efficiency for a*similarly sized*2-engine boat than this single screw? *You'll have to have someone else weigh in that runs twins. *Marin would be a good choice as he has lots of miles under his keel and runs twins. *My answer would only be what I've heard, and not*definitive. I know the fuel*usage*isn't doubled.


3 & 4 I will defer to others, as I haven't a clue without seeing a picture.


5. A boat my size (34') doesn't have enough room to store a dingy on board neatly, but larger boats do indeed store them on the aft cabin, aft deck, or even on the*fly bridge. *Normally you'd use the mast boom or other method to raise and lower the boat. *A friend of mine, with a 50' Marine Trader, stores his dingy on the fly bridge and has an electric davit to lower his inflatable. *There are manual and electric devices out there; just a matter of how large your checkbook is.


Personally, I have my dingy on the system you describe; on the swim step.


Others will have more info for you, but I'd like to welcome to "the dark side" (boating). *A ski trip may help, but we've got you now!


Welcome aboard,




Mike
Brookings, Oregon
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Old 09-20-2010, 06:42 PM   #4
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Basic Trawler questions

nm


-- Edited by one wolf on Monday 20th of September 2010 07:49:31 PM
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Old 09-20-2010, 07:13 PM   #5
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RE: Basic Trawler questions

Here's another one - canvas covered a-frame shaped thing on the deck. *Maybe it's just a hatch lol. *I haven't seen one on a sailboat shaped like that but I'm new to trawlers, who knows.

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Old 09-20-2010, 07:13 PM   #6
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RE: Basic Trawler questions

I'm a new member here as well, bitten by the trawler bug landlocked in NJ!* To answer what those two tems are:

first it is a Doghouse Hatch as Pineapple Girl said, a very traditional design element that was used in "olden days" to keep the waves from crashing through flat hatch covers and to provide weather protected ventilation on the lee-side of the boat.

the second item appears to be a fender covered in a sack to prevent UV damage.
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Old 09-20-2010, 08:11 PM   #7
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RE: Basic Trawler questions

Could the second item be a "lifesling"? Those usually have a rope attached to the railing they hang from. The rope goes into the bag and attaches to the open "U" shaped lifesling.

Fuel economy is directly related to the size of the wave that you make. At 8 knots, my 44000 lb 44 foot trawler gets slightly better than 2 mpg. Doesn't matter whether its one or two engines.

The first item to be identified is definitely a hatch. Mine have gratings of SS wire over the glass, and are varnished teak. The covers are to keep the teak looking good, protection from the sun.

Dinghy storage varies with the availability of space, the weight of the dinghy and its motor, and the preferences of the owner. Just about as many permutations as boats.
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Old 09-20-2010, 08:52 PM   #8
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Basic Trawler questions

We have a DC electric powered mast and a boom to lift the dink up on to the roof.* So lifting the dink up on to the deck is pushing a up/down button.* The winches cast 70 bucks are Harbor Freight Tool.* We also have a steady sail that*is used mostly at anchor to keep the bow into the wind and prevent swinging.* We also have a square front hatch but solid teak wood so not canvas cover.* We are 58 ft, 43 ton, single DD 671 and get 2 miles per gallon.***

What other questions do you have?*


-- Edited by Phil Fill on Monday 20th of September 2010 09:00:01 PM

-- Edited by Phil Fill on Monday 20th of September 2010 09:01:05 PM
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Old 09-21-2010, 06:19 PM   #9
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RE: Basic Trawler questions

one wolf,The difference in efficiency with single and twin screw is fly stuff.*I think twins are more efficient but I think over 50% of Trawler Formers think a single is.*To be meaningful comparing twins and singles one must compare same boats with same total power. The most efficient boat is a full displacement hulled boat and there are very few of them. Your choices are much broader w semi-displacement and the increased fuel consumption is small stuff compared to total boating costs. Twins are more expensive (probably 20% to maintain and 35% to buy new) and are generally better but if one goes aground or runs into things that can damage a propeller the vulnerability of the props on a twin can cost you in various ways.
The "A frame thing" is simply a skylight window on the cabin top.
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Old 09-21-2010, 06:32 PM   #10
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RE: Basic Trawler questions

Quote:
koliver wrote:
Fuel economy is directly related to the size of the wave that you make. At 8 knots, my 44000 lb 44 foot trawler gets slightly better than 2 mpg. Doesn't matter whether its one or two engines.
Thanks - very helpful info. *What RPMs are your twins running at 8 knots?

So you are suggesting that the length, beam, draft, hull shape, and weight are the influencing factors to fuel efficiency, not size or numbers of engine. *Assuming this is the case, then why would anybody want twins over single other than the ability to limp in if one quits of course... *For inland boaters, maintaining two engines sure seems like a high price to pay just to know you have a spare if one quits in the middle of the lake.


Thanks again for all the replies!
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Old 09-21-2010, 07:18 PM   #11
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RE: Basic Trawler questions

Best guess on #4: sea anchor.
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Old 09-21-2010, 07:19 PM   #12
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RE: Basic Trawler questions

Wolf

Some years ago PMM had an ariticle on an NT 50 single and an identical twin. Fuel economy was about a 15 - 20% difference, favoring the single. Not much difference in purchase cost. There are many older singles to choose from under 40 feet, not too many over 45 feet. My 55,000 lb trawler gets 1.5 nmpg at 8 knots with twins running at 1750 RPM. The only single I'd consider for the type of cruising I do would require a decent get home option, which is essentially another engine and drive train - such as with Nordhavn or Selene. Those are very expensive vessels.

For* low price and lots of space in a newer boat,*consider a reasonably new Carver, Bayliner or Searay. twin of course.
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Old 09-21-2010, 08:10 PM   #13
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RE: Basic Trawler questions

Quote:
koliver wrote:Fuel economy is directly related to the size of the wave that you make. At 8 knots, my 44000 lb 44 foot trawler gets slightly better than 2 mpg. Doesn't matter whether its one or two engines
I for one am one of those people who DO BELIEVE that a single engine displacement hull is more fuel and dollar efficient than a twin setup. I just have returned today from a 200 mile trip that I calculated my fuel very carefully, 60,000 lbs, 48' displacement hull single, naturally aspirated John Deere with 2100 hours. 1700 rpm in flat water = 7.9 kts @ 2.3 gph = 3.43 mpg.* The twin suffers a loss in efficiency due to parasitic drag ( two shafts/rudders/struts....and friction caused buy two engines full of whirling gizmo's vs. one.* I am not debating the safety issues... just the fuel and cost issue.* Need to put a lot of horsepower to the water with shallow draft? twins win. Look at all freighters and tankers... they are singles for a reason... cost per mile..
HOLLYWOOD

*
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Old 09-21-2010, 08:46 PM   #14
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RE: Basic Trawler questions

Hollywood, it is not just a belief...it is a FACT!!!
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Old 09-21-2010, 09:57 PM   #15
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RE: Basic Trawler questions

And I think it's not John. But anyone that's interested in the OPINIONS expressed previously on this twin v/s single business can go look in the archives to see all the OPINIONS we expressed in the past. Unless yo'all want to throw all those tomatoes all over again. There's just way too many variables to ever say (objectively) yea or nay.
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Old 09-22-2010, 03:47 AM   #16
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RE: Basic Trawler questions

"1700 rpm in flat water = 7.9 kts @ 2.3 gph = 3.43 mpg"

2,3 gph is at most 50 hp.

Great if the Deere is the 4 cyl 80 hp model, but some harder running at times should be done if its one of the 6 cylinder marinizations.
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Old 09-22-2010, 04:26 AM   #17
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RE: Basic Trawler questions

There are too many very COST efficient +45' trawler twins out there*which muddles the economy discussion.*Economy is more than gph and the number of fuel filters per year. It includes the purchase cost*and resale value too* -- a 50' newer single is*costly to OWN. Just look at the very expensive Selene, Nordhavn, Krogen and*Tugs. Not to mention the plethora of one of a kind steel single engine trawlers that frequent the used boat market.

There are some that read* this forum that own vessels over 45' such as*Offshore, Fleming, Tollycraft, Ocean Alexander, DeFever, Grand Banks, Albin et al. I'm one. I gladly pay the extra $1000 to $2000 per year in fuel, impellers*and filters to be on this list. Unfortunately I don't have the extra $100,000 per year of interest and insurance*payments*to get the big Selene, Watson*or Nordhavn of my dreams.

Last but not least, if life were all about the cheapest way to do something, we would not own any boats nor pay taxes. We'd all be on Obama care railing against those rich*guys..
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Old 09-22-2010, 06:42 AM   #18
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RE: Basic Trawler questions

An interesting test would be to find one of the very few Krogen 42's that were made with twin engines and compare their fuel use / mileage to the standard 42. Think I'll pop over and send a note to the Krogen group.
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Old 09-22-2010, 08:52 AM   #19
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RE: Basic Trawler questions

Eric, I will ask you a very theoretical question...one we can't prove right now.

If we had 2 50 hp Yanmars and one 100hp Yanmar and ran them at 2000RPMs with no load. Do you think the fuel burn would be the same? Or better for either example? And why. Under load?

Also Keith, for it to be a proper comparison the total horsepower would have to be the same.
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Old 09-22-2010, 11:04 AM   #20
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RE: Basic Trawler questions

You can't compare at no load. Useless information.

They need to be compared at some horsepower level. With that kind of comparison you can take the data from a manufacturer's chart and it would be meaningful.

In the past I have compared Cummins engines models*using Cummins data charts and the larger hp engines get better economy at the lower hp levels.

For example a Cummins 6bt 220 at 1600 rpm produces 155 hp using 3.5 gph
A Cummins 6bta 270 at 1400 rpm produces 155 hp using 2.9 gph. (data taken from mechanical enignes circa 2002)

*

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