Mainship 400 - Only Entry Level Trawler for X sailor?

[Bryant]

Mainship 400

Jefndeb
I would take a hard look at the Grand Banks 36 Classic. We have the single engine version. With the V berth and aft stateroom and two full heads it is quite a lot of boat in 36ft.

 

[Dougcole]

We have a watermaker on our Mainship 400. I wish we had propane as well, but it's not worth the trouble to convert.


I've considered solar, and may do it some day, but since we generally run the genset for air conditioning at night it's not critical.

 

[Riverguy]

I’m an x sailor. Got tired of pulling lines. Just bought a 430 Mainship. Great space below but it does have two engines. I’ve been told you can run it on one engine at a time. Has anyone heard that?

While you >>can<< run one engine at a time, you should not (except in an emergency). You will actually increase your fuel consumption, because:

1) With the widely spaced engines, you are applying hugely asymmetrical thrust to the hull, which must be overcome with your rudder. If you have a rudder angle indicator, you will be shocked at how much rudder you need to keep the boat running straight on one engine. Think about the drag that creates.

2) Mainship 430 (and other similar models) have very little keel to keep you running straight forward. It's all on the rudders.

3) In addition to the large hydrodynamic drag from the rudders that are turned 10-20degrees over to keep you straight, you are now dragging a useless propeller through the water. Depending on your transmission, you may be shortening it's life as well.


4) Your rudders were not designed to handle the stresses of overcoming asymmetrical thrust >>constantly<<. Think about the forces acting when a hard prop-wash is directed against a 10-20 degree rudder angle for hours and hours on end.

So...hypothetically...if it takes a total of 60hp from your two engines to move your boat at 8mph, you will find that running on one engine will now require something like 1.5x (or more) the horsepower, so perhaps 90hp.

Remember that diesel engines burn fuel based on how much horsepower they are making -- NOT on how many RPMs they are turning.

If you need yet another analogy...think about how much more energy it takes to paddle a canoe from only one side. You'd never even ask the question "can I paddle from only one side" because it's ludicrous. For some reason however, this question "can I run my twin-engine boat on one engine" keeps getting asked.

 

[Cartouche]

[Here are some things that I have noticed so far-

I also dont see Solar systems on trawlers-
I do not see Propane oven/stoves on trawlers-
I dont see watermakers on trawlers-

Maybe I am weird but if I go to the Islands I would like to have some solar and a watermaker so I dont have to fuss at the boss about her 20 minute showers she takes...(tight quarters have to be careful what you say and how you say it)

I am sure there is a reason, not sure though.

Jeff in Savannah ]

As mentioned we started out doing the same things we did as sailors, and realized very quickly, the boat and experiences were much more fun when we used it as a trawler and understood she likes to be plugged in at night. for example, we used to anchor out in the islands all the time on our sailboat, we now anchor out for the day, and go into a marina at about 5 o'clock, plug in enjoy the ac and the outdoors on the bridge deck, and Make breakfast on the electric stove before pushing off for a 50 mile run to another great destination. We used to travel maybe 50 miles on a 10 day sailing holiday staying on an anchor for 3 days at a time and covering the same piece of water, last year we were a week up the Rideau, down to Brockville, and Montreal and over to the states, we had great friends come up from the Chesapeake for a family reunion, all stuff we would never have considered, that is why you don't see the majority of trawlers having solar, or propane stoves, while under way your batteries are always charging, and we normally run the generator while under way, if we are going to anchor for a day, to make some hot water for dishes, or cook a meal. Theses boats compared to Sailboats use a ton of power Lights for instance on the sailboat one light at night would be ambient and provide enough light to be able to move around down below comfortably, a Trawler not so much. Lights every where 2 stereos depending on where you are sitting, running the AC, Remember on a trawler you are above the waterline, and on a sailboat in the basement below the waterline. and last but not least sleeping on an anchor if the sea is moving even slightly, slap on the hull,

 

[North Baltic sea]

Hi, the fuel economy was also important to me when I last changed the boat.

I found Nordic tug 37 which is +40 'and LWL 37'4 ". Here's my consumption in liters and the speed kn, consuptions come of the smart craft computer. Tanks 100% full and 5 people in boat, bottom clean.

8kn / 2.5 gal per hour. More economical to run 6.5-7.5kn



NBs

 

[Seevee]

While you >>can<< run one engine at a time, you should not (except in an emergency). You will actually increase your fuel consumption, because:

1) With the widely spaced engines, you are applying hugely asymmetrical thrust to the hull, which must be overcome with your rudder. If you have a rudder angle indicator, you will be shocked at how much rudder you need to keep the boat running straight on one engine. Think about the drag that creates.

2) Mainship 430 (and other similar models) have very little keel to keep you running straight forward. It's all on the rudders.

3) In addition to the large hydrodynamic drag from the rudders that are turned 10-20degrees over to keep you straight, you are now dragging a useless propeller through the water. Depending on your transmission, you may be shortening it's life as well.


4) Your rudders were not designed to handle the stresses of overcoming asymmetrical thrust >>constantly<<. Think about the forces acting when a hard prop-wash is directed against a 10-20 degree rudder angle for hours and hours on end.

So...hypothetically...if it takes a total of 60hp from your two engines to move your boat at 8mph, you will find that running on one engine will now require something like 1.5x (or more) the horsepower, so perhaps 90hp.

Remember that diesel engines burn fuel based on how much horsepower they are making -- NOT on how many RPMs they are turning.

If you need yet another analogy...think about how much more energy it takes to paddle a canoe from only one side. You'd never even ask the question "can I paddle from only one side" because it's ludicrous. For some reason however, this question "can I run my twin-engine boat on one engine" keeps getting asked.

Riverguy,

I could argue that your facts are a bit exaggerated. I'd like to see some real numbers as to how much rudder and extra power it takes to operate on one. I'd bet it's minimal, and the the single engine operation will be NOT CLOSE to 1.5 times as much. You're thinking airplanes and even they don't require 1.5 times the power.

Yes, there will be more when accelerating because more power is being applied when the rudder is less effective.

As for experience, the times I've come home on one, the rudder deflection has been minimal.

As for the canoe, you need to try the J stroke and hold your paddle closer to the boat and you can paddle wherever you want from one side AND turn left or right. It takes less effort to just twist the paddle to straighten out that to swap sides. And the J part of the stroke is probably 5% of the power. I do that all the time.

Now, if it's actually "productive" to shut one down for efficiency, I suspect not, only because of the drag of the non producing prop.

 

[Wayne]

Propane on Trawlers

[Here are some things that I have noticed so far-

I also dont see Solar systems on trawlers-
I do not see Propane oven/stoves on trawlers-
(Remainder deleted as it was not pertinent to this response.)

The Celestial, an Albin 43 Sundeck Trawler had a propane oven and galley stove.
QUOTE]

 

[Comodave]

Very true indeed, well I am just up the road in Savannah, maybe I could crew on your MS one day.???...Does anybody ever install a SSB Radio on the Mainship...I ask because I do not see a nav station or a place where one might be installed..

We were bring a 46’ trawler that I had brought from Seattle to LA. One of the crew was a ham radio operator. He temporarily installed some sort of han radio on the boat. We were able to talk all over the country with it. I am not a ham so I really didn’t pay attention to what type of radio it was, but it seemed to work quite well.

 

[IndigoStar]

The first owner of our Mainship 400 (2006) installed a SSB. i will take some photos later and post on our blog: https://saileagleswings.blogspot.com/

 

[Riverguy]

Riverguy,

I could argue that your facts are a bit exaggerated. I'd like to see some real numbers as to how much rudder and extra power it takes to operate on one. I'd bet it's minimal, and the the single engine operation will be NOT CLOSE to 1.5 times as much. You're thinking airplanes and even they don't require 1.5 times the power.... (snip)

Hi Seevee,

No, I am not thinking about airplanes at all -- that would be dumb.

Hydrodynamics and aerodynamics are two utterly different things. While they both deal with fluid dynamics, air is a compressible 'fluid' and water is not. Airplane propellers can be 'feathered', OP's props cannot. Airplanes have many control surfaces that can be used to compensate for asymmetrical thrust, OP's boat has rudders only.

Bringing airplanes into discussions about boats only creates confusion.

Some additional facts:

The rudder deflection required is primarily a function of (a) how far apart are the engines and (b) how much 'rudder' is being provided by the keel. With one prop pushing and one prop dragging, the thrust vector will far off the centerline. Twin-screw boat owners who 'drive with the sticks' already know how fast their boats will turn when you put one engine in neutral. Now...while your MS400 has a pretty decent keel (like my 390), in the Mainship 430, the keel is much smaller and almost insignificant.

Re: "I could argue that your facts are a bit exaggerated."

I'd be happy to hear your argument, but I'll bet it comes from a near-universal misconception that goes like this:

"My engine's documentation (propeller demand curve) tells me I am burning 6gph (per engine) at 1,400 rpm. At these RPMs I am going 10mph. When I shut off one engine, I stay at 1,400rpm but my speed only drops from 10mph to 8mph. So, on two engines...10mph @ 12gph = 0.83mpg. On one engine I have 8mph @ 6gph = 1.33mpg. See how much fuel I can save!!"
​

Every argument I have ever seen for running a twin-screw boat on one engine goes like that. I have seen it over and over again, even here on Trawlerforum. It's totally bogus, but it STILL gets debated over and over again!

The problems with this argument? (a) as soon as you shut off one engine, the gph numbers from your engine demand curve go straight out the window. The engine is still turning 1,400 rpm, but it is now producing roughly 1.8x more horsepower, and BURNING 1.8x MORE FUEL. (b) You are now running GROSSLY overpropped! In a twin-engine boat, the engines are matched to propellers based on a load curve that assumes each engine is doing half the work.

For some reason, people just don't get it that diesel engine fuel consumption is NOT a function of RPM. Rather, it is a function of how much horsepower the engine is making.

While marine diesel engine experts will acknowledge the above as totally obvious, it seems to escape most diesel-powered boat owners.

Fortunately there is a very easy way to confirm the truth of this. At cruise speed, try shutting down one engine while maintaining RPMs and monitoring your EGT. EGT increases with the horsepower produced and fuel burned. You will see EGT spike up sharply. Now...try to increase RPMs on one engine to get back up to your original speed, while watching your EGT. EGT will skyrocket and you will probably now be seeing black smoke. Of course this is because you are now overloading an engine that is now also grossly overpropped.

In addition to our MS390 (single Yanmar), I also own a Bayliner 4788 with twin Cummins 370's. On a recent 1,000 mile trip, one of the transmissions started to sound funny, so I shut down that engine for about three hours until I could make port. Now...the displacement and the keel configuration of my 4788 and the MS430 are very similar. I needed more than 10 degrees rudder to keep the boat running straight, and I could not go faster than about 6.5 mph without pushing my EGT to it's limits. At 8.5mph on one engine EGT briefly went above 750 degrees. Normal EGT at that speed running on two engines is well under 500 degrees.

In addition to the fact that running on one engine will not save any fuel, I would also consider it 'engine abuse'.

 

[Seevee]

Hi Seevee,

No, I am not thinking about airplanes at all -- that would be dumb.

Hydrodynamics and aerodynamics are two utterly different things. While they both deal with fluid dynamics, air is a compressible 'fluid' and water is not. Airplane propellers can be 'feathered', OP's props cannot. Airplanes have many control surfaces that can be used to compensate for asymmetrical thrust, OP's boat has rudders only.

Bringing airplanes into discussions about boats only creates confusion.

Some additional facts:

The rudder deflection required is primarily a function of (a) how far apart are the engines and (b) how much 'rudder' is being provided by the keel. With one prop pushing and one prop dragging, the thrust vector will far off the centerline. Twin-screw boat owners who 'drive with the sticks' already know how fast their boats will turn when you put one engine in neutral. Now...while your MS400 has a pretty decent keel (like my 390), in the Mainship 430, the keel is much smaller and almost insignificant.

Re: "I could argue that your facts are a bit exaggerated."

I'd be happy to hear your argument, but I'll bet it comes from a near-universal misconception that goes like this:

"My engine's documentation (propeller demand curve) tells me I am burning 6gph (per engine) at 1,400 rpm. At these RPMs I am going 10mph. When I shut off one engine, I stay at 1,400rpm but my speed only drops from 10mph to 8mph. So, on two engines...10mph @ 12gph = 0.83mpg. On one engine I have 8mph @ 6gph = 1.33mpg. See how much fuel I can save!!"
​

Every argument I have ever seen for running a twin-screw boat on one engine goes like that. I have seen it over and over again, even here on Trawlerforum. It's totally bogus, but it STILL gets debated over and over again!

The problems with this argument? (a) as soon as you shut off one engine, the gph numbers from your engine demand curve go straight out the window. The engine is still turning 1,400 rpm, but it is now producing roughly 1.8x more horsepower, and BURNING 1.8x MORE FUEL. (b) You are now running GROSSLY overpropped! In a twin-engine boat, the engines are matched to propellers based on a load curve that assumes each engine is doing half the work.

For some reason, people just don't get it that diesel engine fuel consumption is NOT a function of RPM. Rather, it is a function of how much horsepower the engine is making.

While marine diesel engine experts will acknowledge the above as totally obvious, it seems to escape most diesel-powered boat owners.

Fortunately there is a very easy way to confirm the truth of this. At cruise speed, try shutting down one engine while maintaining RPMs and monitoring your EGT. EGT increases with the horsepower produced and fuel burned. You will see EGT spike up sharply. Now...try to increase RPMs on one engine to get back up to your original speed, while watching your EGT. EGT will skyrocket and you will probably now be seeing black smoke. Of course this is because you are now overloading an engine that is now also grossly overpropped.

In addition to our MS390 (single Yanmar), I also own a Bayliner 4788 with twin Cummins 370's. On a recent 1,000 mile trip, one of the transmissions started to sound funny, so I shut down that engine for about three hours until I could make port. Now...the displacement and the keel configuration of my 4788 and the MS430 are very similar. I needed more than 10 degrees rudder to keep the boat running straight, and I could not go faster than about 6.5 mph without pushing my EGT to it's limits. At 8.5mph on one engine EGT briefly went above 750 degrees. Normal EGT at that speed running on two engines is well under 500 degrees.

In addition to the fact that running on one engine will not save any fuel, I would also consider it 'engine abuse'.

River guy

You have the concept, just not the numbers and the experience of others back this up.

Granted, if you shut one down, you will not make the same speed unless you have big engines. But you won't consume 1.5 times the amount of fuel that you were running on two engines.

On this forum:
http://www.trawlerforum.com/forums/s11/mainship-430-twin-engine-42550.html

Look at the PDF in post 5, prepared by a boatyard expert on two boats.

My personal experience shows the same. Granted, with one engine out, you will burn a bit more fuel per mile (as you're dragging the stopped or windmilling prop), and you will go slower, just because you have less horsepower. But not as much as you imply.

Granted, the props are pitched for two engine operation so if you shut one down and expect to maintain speed, you will have to get a LOT more HP from the working engine, perhaps double or a bit more. If you have really big engines, perhaps you can maintain speed without overworking the engines..... depends.

And I'm not sure that EGT is a good indication of work or overworking a water-cooled engine. How many boats do you know have EGT meters? Do you have them? A torque meter would be much better. Without that RPM is still the parameter for power as set by the manufacturers, but does need a prop pitched so that the max rpm can be obtained. And, of course, we always monitor temp.

And example might be:
If you're cruising on two engines (Yanmar 370s found on the MS 430) at 1600 doing about 7 knots, and you're consuming ~4 mph total. And one quits.
You could most likely continue on one with the one running around 2400 rpm during about the same and loose perhaps a knot.
Just a wag, never tried it, but bet it would be close and the speeds would be close

As folks if there were able to still maneuver and operate safely with their engine out situation, and the vast majority have no problems.

If you have some specs, please post. Would be interesting. I've got more if I can find them.