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Old 12-26-2012, 09:04 PM   #21
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O have an Schooner in Brazil , a 44' that has an old Yanmar BT 33, a small engine that burns 1,3gal/hr cruising at almost 7 knots.I think that if you cruise at the ideal hull speed , you can use low HP and low fuel burn.

Sergio "Alemao" Sztancsa, Sent from my iPhone using Trawler
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Old 12-26-2012, 09:10 PM   #22
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I would look into taking the turbos off...even if you had to change injectors...the fuel savings over 6000 miles may come back pretty quick ...especially if you sold working tubos...my 375hp Cat turbos were several thousand a piece used.

One engine operations are no big deal if you take the proper precautions on the dead engine gearbox.
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Old 12-27-2012, 05:28 AM   #23
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The phone of my mechanic is 3208, I heard about him for one year and finaly I asked him to see my engines.
He found a manifold leaking and I have to change it. The cost is $ 2,400 as a new part and he found an used for $ 1,600.
He really knows everithing about those engines and teache us about that
I forgot the idea to work with one engine each time.
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Old 12-31-2012, 07:22 AM   #24
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"The way i understand it is it dosent take much horsepower to attain hull speed and after hull speed is attained tripling the horsepower wont gain you hardly anymore speed. I thgink the calculation is the sqaure root of your waterline length times 1.30 to find your hull speed."

" I'll run the 2 engines but maybe slow to burn a little less fuel"

The square RT of the underway length on the waterline ( SL) times .9 to 1.1 will give the most economical speed.

Run at "hull speed" where the SL is multiplied by 1.34 or so and it will usually double the fuel burn , and most folks wont gain but 1 12 or 2K

IF your 55 ft boat is 49 on the waterline 7K would be first choice for cruise , ryn to hull speed at perhaps 9K it will cost 2X the fuel per hour.

Attempt to travel faster than hull speed requires a full plaining boat , and yes sometimes the fuel burn at speed goes down a bit , but at 25+K and perhaps 25GPH , who cares?

Most marine transmissions (and some stuffing box systems) will have a lubrication.problem with a prop freewheeling.

Its crude but a big pipe wrench , put in place while stopped will hold fine.

A shot of reverse will usually drop the wrench if the second engine is required.

Removing the prop is one solution as the drag of a prop locked is the same as towing a pail behind of the same diameter, the drag from a spinning not locked prop will be 50% to 100% HIGHER!

Good cruising. 7K takes getting used to , but usually will result in 150+nm per day , even as you will be against the wind and prevailing current going to PR.
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Old 01-01-2013, 04:47 PM   #25
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FF. O agree with you, my idle is 6,7knots and I'll cruise at 7/8 knots. It will burn about 6/7 gal/hr. I think it's good be oust I have small tanks. Twice 200 plus a bladder tank with 150, I intend to put 2 drums with 55 each one.

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Old 01-01-2013, 06:41 PM   #26
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It has to do with the circulation of the lubricant in the transmission, or lack of it.....
It also has to do with the lubrication and cooling of the shaft logs. If they require a raw water feed from the engine's cooling system--- as ours do-- the shafts cannot be freewheeled even if the transmissions can. Without the cooling feed from the engine the shaft log will get extremely hot in a very short period of time and severe damage to the log and even the shaft will most likely occur.

This is why we have to tie the unpowered shaft off in our boat in the event of an engine shut-down. And a locked prop creates a lot more turbulence in the water--- which is drag--- than a freewheeling prop. So if you have to lock the shaft to protect the transmission or shaft log or both, the drag from that locked prop may well negate the fuel savings from running on just one engine.
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Old 01-02-2013, 06:44 AM   #27
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And a locked prop creates a lot more turbulence in the water--- which is drag--- than a freewheeling prop.

Not so, sail boat testing does not show this ,and after all an aircraft with a stopped but not feathered prop has tiny drag compared to a windmilling prop.

Props are built to be very effective , so spinning , being spun can cause huge drag.

AS a mental exercise IF the prop spins at 50% of the speed of the operating engine, look up the HP required to spin the shaft at that 1/2 speed.

It is a remarkably large number .
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Old 01-02-2013, 11:47 AM   #28
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Not so, sail boat testing does not show this ,and after all an aircraft with a stopped but not feathered prop has tiny drag compared to a windmilling prop.
.
I think FF is correct but I'd sure like to see other pilots input.
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Old 01-02-2013, 12:04 PM   #29
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Attched is an aticle on freewheeling vs locked shaft that says, "lock the shaft".

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Old 01-02-2013, 12:42 PM   #30
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Great, a lot of GURUs talking about my fuel consumption ) I`m reading and learning
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Old 01-02-2013, 01:31 PM   #31
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I'm from the lock the shaft camp also...whenever a USCG cutter lost an engine/motor...they locked the shaft too because of drag (maybe tranny too...but every engineer agreed the drag burned a lot of extra fuel)
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Old 01-02-2013, 01:40 PM   #32
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If I run with one engine and the other one just in idle to lubricate.
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Old 01-04-2013, 05:08 PM   #33
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How must I checkout from the States?
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Old 01-04-2013, 05:16 PM   #34
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How must I checkout from the States?
I don't think anyone cares if you leave. Not to make it sound as if I'm being snide or rude, but I've never knowingly gone through customs when leaving the US. Get on the plane and go, get in the car and drive. Never left the US by boat before, but there's always a first.

If you want to be sure you won't be hunted down for not filing Form 2346.3(b) (or whatever) contact the Coast Guard and see if there is anything you need to do.
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Old 01-04-2013, 06:09 PM   #35
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When I arrive in the States, the customs attach to my Passport a little withe piece of paper thats the air company got when we depart.
Must I deliver this paper to the customs?
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Old 01-05-2013, 06:12 AM   #36
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When I arrive in the States, the customs attach to my Passport a little withe piece of paper thats the air company got when we depart.
Must I deliver this paper to the customs?
I am assuming you are traveling on a Brazilian passport not US so I would stop at Customs and Immigrations before departure. If you ever return to the US or have to renew your visa, your passport may be flagged if you haven't closed the loop. These agencies, both have long memories which is even more reason to go see them.
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Old 01-05-2013, 06:28 AM   #37
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[QUOTE]I don't think anyone cares if you leave... [QUOTE]

In most cases this is correct, when you leave by boat. The arrival country is where the problem is. Once you get out of North America most counties require a zarpe or a copy (s) of your check out paper work and crew lists (with a minimum of 6 months remaining on everyones passports) before they will allow you to land. As US citizens, countries such as Brazil, NZ, OZ and some others require that you have a valid VISA in addition to a zarpe prior to your arrival.
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Old 01-05-2013, 06:40 AM   #38
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If I run with one engine and the other one just in idle to lubricate.

About 50% of the RPM the engine that is moving the boat would have least drag for the "ideling ' engine.

US citizens do not have to clear outbound , but you will.

Usually its a trip to the INTL local air port , perhaps a trip to the customs office.

Call customs to find out where.

Almost anywhere you go will ask to see the departure clearence from your last stop.

Get used to clearing in & out , you will do it almost everywhere.

Also get a courtesy flag for each country you plan on visiting.

The fine for not having one may be high.

Bon Voyage!
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Old 01-12-2013, 02:30 PM   #39
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Question: Lightning Rod. Is it important ? I don't see in other boats but a friend of mine got a lightning and burned all of his electronics.
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Old 01-12-2013, 02:52 PM   #40
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Greetings,
I would suggest that your missing manifold bolt is more important than a lightening rod.
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