Mainship 400 vs 390 performance

Dougcole · Oct 5, 2012

OK, in our new boat search we are starting to get pretty serious about the Mainship 390 and the 400. We want a minimum cruise speed of 15 knots (we will often cruise at displacement speeds, but we want to be able to COMFORTABLY run that speed). We are only interested in twin engine models.

It is my impression that the 390 is pretty much the same hull as the 350 except with a more substantial swim platform glassed/bolted to the transom. I assume they did this to try to reduce the squat. I'm pretty sure that the 350 hull was designed to run at 7 to 8 knots, and the only way to get more from it is to pour on the HP, resulting in a pretty inefficient boat at higher speeds. Am I correct in these assumptions?

Is this also the case with the 400? Since this design started about 2002, did Mainship design it from the get go anticipating higher cruise speeds?

Thanks in advance.

Doug

Dougcole · Oct 8, 2012

wow, not one response, really unusual for this board. Anybody know of perhaps a good Mainship forum where I could ask the same thing? I found a couple via google, but they didn't show much activity.

Thanks

sunchaser · Oct 8, 2012

Doug:

15 knots cruise from a 39, even with twins may prove challenging. Have you been on one where 15 knots is possible at 400 RPM off the top RPM without overheating? Luhrs designed exhaust elbows have received some criticism, look carefully for any sign of saltwater backup into the turbo and # 6 cylinder. Mainship twins suffer from a very crowded ER especially given the ER's limited height. Check to see normal inspections, servicing and maintenance access is possible - each install was different since Cat, Yanmar, single, twin, genset sizing were utilized.

The 40 was intended to be an improvement over the 39 based upon owner feedback. Lots of flybridge space makes it a great choice for warmer climes and hanging out at anchor. Too bad Luhrs fell into financial troubles 6 years or so ago, the 39, 40 43s were headed in the right direction.

David O · Oct 8, 2012

Sorry, Doug, I would of responded but I was going to see what everyone else had to say.

Your assumptions are correct. I have a 98, 350 with twin 4LH DTE 170 HP Yanmars in it. Yes, the ER is tight but not as bad as you might think. I installed a remote oil filter kit on the starboard engine and solved most of the maintenance headaches. Now, I still dread replacing the port impeller. But, I accept the fact that I must remove the pump to do it. Usually 1.5 hours tops.

I think the 350 and 390 are identical in every way except the model number. I have been told it was an attempt to market the boat overseas where the model number must match the LOA. I have a neighbor who has a 99 390 and there is no difference in the boats.

As far as the performance, no, do not expect a 350/390 to run at 15 knots comfortably. WOT is 17 to 19 MPH (depending on wind and current) on my boat and it just does not feel natural. 8 to 11 MPH does. The difference between 8 MPH and 11 MPH is 3.5 gallons/hour to 5 gallons/hour. The 170 hp twins in my boat were unusual. The PO made the choice. I have owned the boat for 7 years. Volvo 220 hp twin engines were the more common choice. I have never been in the ER of one of those. I am sure it is very tight. There is 150 gallon fuel tanks on each side with the holding tank in the middle.
I know nothing of the 400 except for walking through them at boat shows and appreciating the extra space in the cabin, upper deck and overhang on the side decks. They also solved the short comings of the 350/390 including the 'well' outside of the lower helm door, the head banger over the master state bed, the "box" stuck on the transom and a few other details. 400's are consistently priced at about $100k over the 350/390. I guess you have to draw the line somewhere......I have a 350!

Here is a good website of a 400 owner, lots of good stuff that might answer some of your questions. Steven Cyr's Stella Blue Site

Good luck.

Dougcole · Oct 8, 2012

Thanks Guys,

That is my real concern about the 390, will it perform the way we want it to? I haven't run either boat yet, that is the problem with used boat shopping, until you reach accepted offer stage a sea trial is tough to get, even if you are a serious buyer like us.

I've seen the Stella Blue site, it is a wealth of useful information on the 400, but his boat has a single. He indicates that he feels his boat is best at displacement speeds, but admits that he doesn't have much valuable input on the twins.

David, twin 170's sound great from a space and fuel burn consideration, but they give a lot less HP than the Yanmar 240 hp that are in the 400's usually. 340 hp vs. 480 is pretty significant, do you think that combined with a more modern hull shape would be enough to turn the perfomance factor in our favor?

The owners of both the 400 twins I have looked at say that they run good at 15 knots, I believe them, but I'd like an independent opinion.

We sold our old boat because due to our current life situation (busy business and busy kids) we just don't have as much time as we would like to make long cruises. If we could cut by 1/2 the two long runs (Carrabelle to West Palm and West Palm to West End) that we make to the Bahamas it would make our lives a whole heck of a lot easier.

millennium · Oct 8, 2012

My year 2000 390 has twin Yanmar 230hp, the 4lha-ste's.

It will do 16k wot, fast cruise 3000 rpm about 13k. Big wake and fuel bills.

Normal cruise is 1400 rpm, 7 knots. If in no hurry I go 1200 one only, 5 k. Go forever on a tank of fuel.

johnma · Oct 8, 2012

Try this; it's a pretty active group.

mainship : This list is for Mainship Owners and others who want to own a Mainship.
I cannot speak for twins, my 2003 390 has a single 370 Yanmar. Normal cruise is 7-10 kts. On a good day I can probably do 14-15 kts at wot. I only did that once to see what wot was. As stated the 350 and 390 are the same boat with some minor interior differences. I'm told that hull #1 did not have the large swim platform and handling was poor. The "bustle" fixed that. The 400 has about 8 more inches of headroom in the engine compartment, the salon is about 2-1/2' longer and the hull is longer because they did not include the bolt on swim platform in the loa number.
If you want to run 15 kts I don't think the 390 is for you. there is a lot of 400 guys on the yahoo group. You should be able to get some good info there.
John
MS390

H2oplayer · Aug 2, 2015

Remote oil filter

David O said:
Sorry, Doug, I would of responded but I was going to see what everyone else had to say.

Your assumptions are correct. I have a 98, 350 with twin 4LH DTE 170 HP Yanmars in it. Yes, the ER is tight but not as bad as you might think. I installed a remote oil filter kit on the starboard engine and solved most of the maintenance headaches. Now, I still dread replacing the port impeller. But, I accept the fact that I must remove the pump to do it. Usually 1.5 hours tops.

I think the 350 and 390 are identical in every way except the model number. I have been told it was an attempt to market the boat overseas where the model number must match the LOA. I have a neighbor who has a 99 390 and there is no difference in the boats.

As far as the performance, no, do not expect a 350/390 to run at 15 knots comfortably. WOT is 17 to 19 MPH (depending on wind and current) on my boat and it just does not feel natural. 8 to 11 MPH does. The difference between 8 MPH and 11 MPH is 3.5 gallons/hour to 5 gallons/hour. The 170 hp twins in my boat were unusual. The PO made the choice. I have owned the boat for 7 years. Volvo 220 hp twin engines were the more common choice. I have never been in the ER of one of those. I am sure it is very tight. There is 150 gallon fuel tanks on each side with the holding tank in the middle.
I know nothing of the 400 except for walking through them at boat shows and appreciating the extra space in the cabin, upper deck and overhang on the side decks. They also solved the short comings of the 350/390 including the 'well' outside of the lower helm door, the head banger over the master state bed, the "box" stuck on the transom and a few other details. 400's are consistently priced at about $100k over the 350/390. I guess you have to draw the line somewhere......I have a 350!

Here is a good website of a 400 owner, lots of good stuff that might answer some of your questions. Steven Cyr's Stella Blue Site

Good luck.

Do you have the part number for the remote oil filter kit. I have the 4lh series engine as well.

Dougcole · Sep 28, 2015

I started this thread almost three years ago, and just saw it again, so I figured I'd put a period on the end of it.

We ended up buying a 2005 400 in February of 2013 with twin Yanmar 4LHA-Stp, 240 hp. It had about 200 hours on the motors and 125 on the Genset, barely used.

Since then we have made 5 Bahamas trips and 2 runs from Carrabelle down to the SE coast, I've put about 400 hours on the boat.

We are very pleased. I tend to run it about 60/40 hull speed to fast cruise. Fast cruise is 2850 RPM which is between 13.5 and 16 knots depending on sea state. It handles a chop really well at fast cruise. Big swells in a following sea require active steering from the helmsmen at any speed.

Our last Bahamas trip was three weeks total from Stuart to Bimini, Bimini to the Berry Islands, a week or so poking around in the Berrys, then Berrys to Hole in the Wall, Abaco then back through the Abacos to West End, Grand Bahama and on to Stuart. Over the course of the three weeks we averaged 10.43 GPH including genset use. We put about 110 hours on the genset (it was July, so AC was a neccesity).

Not too much I don't like about the boat. I stripped off the enclosure from the genset to provide better access.

Tigs · Aug 18, 2017

Dougcole said:
I started this thread almost three years ago, and just saw it again, so I figured I'd put a period on the end of it.

We ended up buying a 2005 400 in February of 2013 with twin Yanmar 4LHA-Stp, 240 hp. It had about 200 hours on the motors and 125 on the Genset, barely used.

Since then we have made 5 Bahamas trips and 2 runs from Carrabelle down to the SE coast, I've put about 400 hours on the boat.

We are very pleased. I tend to run it about 60/40 hull speed to fast cruise. Fast cruise is 2850 RPM which is between 13.5 and 16 knots depending on sea state. It handles a chop really well at fast cruise. Big swells in a following sea require active steering from the helmsmen at any speed.

Our last Bahamas trip was three weeks total from Stuart to Bimini, Bimini to the Berry Islands, a week or so poking around in the Berrys, then Berrys to Hole in the Wall, Abaco then back through the Abacos to West End, Grand Bahama and on to Stuart. Over the course of the three weeks we averaged 10.43 GPH including genset use. We put about 110 hours on the genset (it was July, so AC was a neccesity).

Not too much I don't like about the boat. I stripped off the enclosure from the genset to provide better access.

Hi Im looking to buying the same boat a 400 with two yanmars 4LHA-STP/240hp 2004 model , can you give me an update of pros and cons ...thanks

Dougcole · Sep 11, 2017

Cons would be generator access, some shoddy wiring installation. We have developed some odor out of the vent when the vacu flush is flushed, I think it needs a new, larger vent line, which is going to be a bot of a bear to replace. Or I may try a bubbler in the holding tank.

I wish the boat was a little faster and ran a little flatter at faster speeds. Steering with bigger following seas is a bit of a challenge as mentioned above. These things are not unique to the 400 or trawlers in general though.

Overall, 4 years in, I love our boat. She has treated us really well.

If you are buying one, look at the condition of the canvas, enclosure and cushions on the flybridge. They are a big expense when they have to be replaced. There is a lot of fabric up there. Roughly $6,000 for the bimini and enclosure, $3,000 for the cushions.

Pmcsurf1 · May 31, 2020

"I stripped off the enclosure from the genset to provide better access."

I did also. What a job that was. We bought our 2004 MS 400 back in April 2020. Our generator had problem overheating. Stupid cover didnt allow you to check or fill coolant. Removed it all and now have access to everything.
Fyi gen set is Kohler 8kw with 3500 hours and the main is a single Yanmar 370hp 6lya-stp with just over 1000 hours.

Blue Tortuga · Jun 1, 2020

Dougcole said:
Cons would be generator access, some shoddy wiring installation. We have developed some odor out of the vent when the vacu flush is flushed, I think it needs a new, larger vent line, which is going to be a bot of a bear to replace. Or I may try a bubbler in the holding tank.

Install the dometic in line holding tank vent anywhere in the holding tank vent lime and that will solve the tank vent odor. Accessing that tank to install a bubbler requires removal of the floor. It worked on my 2004 MA400

Dougcole · Jun 2, 2020

Blue Tortuga said:
Dougcole said:

Cons would be generator access, some shoddy wiring installation. We have developed some odor out of the vent when the vacu flush is flushed, I think it needs a new, larger vent line, which is going to be a bot of a bear to replace. Or I may try a bubbler in the holding tank.

Install the dometic in line holding tank vent anywhere in the holding tank vent lime and that will solve the tank vent odor. Accessing that tank to install a bubbler requires removal of the floor. It worked on my 2004 MA400

Click to expand...

This is a really old thread. A year or so ago I installed a new, larger vent that exits the hull just below the anchor locker. It works great, no more holding tank odor.

The holding tank sender is stuck though, and inaccessible, so I'm going to put a pie plate in the floor right above it so I can pull it out. It will be hidden when the companionway steps are down.

garmstro55 · Jun 3, 2020

Dougcole said:
Blue Tortuga said:

This is a really old thread. A year or so ago I installed a new, larger vent that exits the hull just below the anchor locker. It works great, no more holding tank odor.

The holding tank sender is stuck though, and inaccessible, so I'm going to put a pie plate in the floor right above it so I can pull it out. It will be hidden when the companionway steps are down.

Click to expand...

Hey Doug, as bad as this sounds, I'd ask if you could take some pics of this operation. My sender is also stuck and, so far, NoFlex is not freeing it up. I would like to get it working again and had the same thought to put a deck hatch in the floor above the sender. Also dimensions as to where you put the hole would be great.

Pmcsurf1 · Jul 28, 2020

2004 MS 400 single Yanmar 6lpa-stp with 5 blade prop. Just cleaned bottom. Took it out today after replacing a cracked sea strainer bowl.
I'll post pics. Head wind but maybe 1 knot of following current.
WOT 3200 rpm 10.6 to 11 knots
2700 rpm 9.8 to 10 knots
2400 rpm 9.5 knots
1800 rpm 8.0 knots
1500 rpm 6.7 to 7 knots
1000 rpm 5.0 knots
There is no way I could come close to 15 knots. Maybe with twins and going downhill. OP said he wants min of 15. Don't see it in a trawler style hull.
I understand a 36 foot water line has a hull speed of 8 knots. I usually cruise around 6 to 8 at 1500 to 1800 rpms.

Screenshot_20200728-130843_Boating%20HD.jpeg

Screenshot_20200728-131403_Boating%20HD.jpeg

Screenshot_20200728-132659_Boating%20HD.jpeg

Dougcole · Aug 2, 2020

Pmcsurf1 said:
2004 MS 400 single Yanmar 6lpa-stp with 5 blade prop. Just cleaned bottom. Took it out today after replacing a cracked sea strainer bowl.
I'll post pics. Head wind but maybe 1 knot of following current.
WOT 3200 rpm 10.6 to 11 knots
2700 rpm 9.8 to 10 knots
2400 rpm 9.5 knots
1800 rpm 8.0 knots
1500 rpm 6.7 to 7 knots
1000 rpm 5.0 knots
There is no way I could come close to 15 knots. Maybe with twins and going downhill. OP said he wants min of 15. Don't see it in a trawler style hull.
I understand a 36 foot water line has a hull speed of 8 knots. I usually cruise around 6 to 8 at 1500 to 1800 rpms.
View attachment 105603 View attachment 105604 View attachment 105605 View attachment 105606 View attachment 105607 View attachment 105608

I am the OP in this thread, which is 8 years old, but seems to pop up every once in a while.

We bought a 2005 MS 400 with twins not long after the original post. After 8 years of ownership and quite a bit of use in all conditions, I can tell you for an absolute certainty that our boat will run 15 knots at 2,900 RPM with the tabs down in moderate conditions and half load. WOT, light load, clean bottom is about 19 knots.

We just crossed the stream to the Bahamas and came back last month. On the way over, with a 11 foot dinghy and 20 hp motor on the stern, full fuel and water tanks, a months worth of food and gear, two paddle boards, a portable water maker, and God knows what else on board we averaged 13.5 knots. That is heading ESE against the gulf stream in smooth conditions at 2,800 rpm.

Coming back, lighter load, 1/4 water, 1/2 fuel, with the stream on our stern quarter and a slight following swell, we averaged 15.2 knots. I saw 17 knots a couple of times, but that was surfing down a wave face.

I knew that the twin version was much faster, but not that much. Eight knots at WOT, 75% faster? Wow. Also, 1,850 RPM, which is our slow cruise speed, varies between 8.2 and 9 knots on our boat. Sometimes it will fall into the sevens at that speed, but only if I am fighting a strong current or banging into waves.

Pmcsurf1 · Aug 2, 2020

I have a bad habit of not looking at original posting dates. Sorry.
Congratulations on your MS. I'm impressed with your speed. Twins definitely seem to make a difference.
I'm curious about your props. I've got a 26 inch 5 blade. Smooth but also slower is my understanding.
Also. If you don't mind me asking... gph?

Dougcole · Aug 2, 2020

Pmcsurf1 said:
I have a bad habit of not looking at original posting dates. Sorry.
Congratulations on your MS. I'm impressed with your speed. Twins definitely seem to make a difference.
I'm curious about your props. I've got a 26 inch 5 blade. Smooth but also slower is my understanding.
Also. If you don't mind me asking... gph?

No problem, I apologize if I sounded snarky. We are only a few days back in the US from our long Bahamas trip and had to rush home to prep (albeit not as much prep as usual) for a hurricane and my nerves are jangly I think. Culture shock is a bear.

I'm honestly not sure on my props, but that could be an influence for sure.

I'm more in tune with GPH, as I watch that as closely as I can by tracking hours between fill ups. It's not the most accurate way, I know, and has some room for error, but now that I have been doing it for 7 years and get consistently the same readings, I feel like it is pretty accurate. The one thing that kind of throws me off is that we tend to mix slow cruise (1850 rpm) with fast cruise. I've done a few trips though where I start with full tanks, run for 110 miles across to the Bahamas and fill up as soon as we pull in. Anyway, here goes:

7.5 to 9 knots (1850 rpm) 4 gph. 4.5 if loaded heavy.
13.5 to 15.5 knots (2,800 RPM) 12 Gph.

Over the course of 17 Bahamas trips, 3 to 5 weeks each, with a mix of slow cruise and fast, perhaps 65/35 slow to fast including pretty significant generator run time (8 to 12 hours per day) we have averaged right at 10 GPH.

I keep my crossover valve closed so my generator only pulls from the port tank. I fill up and subtract the amount the stb side takes from the port side to get gen-set burn rate. It's right at .4 gph. When estimating what I will burn prior to a trip I figure in .5 GPH for the genset, just for a safety factor, but it's usually like .36 to .38 GPH.

Again, not scientific, but it's real world numbers over 7 years.

boan400 · Aug 22, 2020

Doug
It’s quite possible to take the holding tank out without remove the hole floor, just some inches in the end. Then you polling it back and lift it up in the stern end.
With a piece of the floor removed the level gauge will allways be able to reach. Cover the missing floor part with a plate of aluminium and make it with a step and cover the pump at the same time.
To get rid of the odor you exchanges the vent hose in the front of the thank to a quite bigger one and let it out in the bow just unde the anchor and then make a second vent line from the rear end of the tank to the existing hull vent. But make sure it’s open air circulations in the old one. With a good cross ventilation in the tank it will not be any smell at all. I have had it for several years now.
Good luck

Dougcole · Aug 22, 2020

boan400 said:
Doug
It’s quite possible to take the holding tank out without remove the hole floor, just some inches in the end. Then you polling it back and lift it up in the stern end.
With a piece of the floor removed the level gauge will allways be able to reach. Cover the missing floor part with a plate of aluminium and make it with a step and cover the pump at the same time.
To get rid of the odor you exchanges the vent hose in the front of the thank to a quite bigger one and let it out in the bow just unde the anchor and then make a second vent line from the rear end of the tank to the existing hull vent. But make sure it’s open air circulations in the old one. With a good cross ventilation in the tank it will not be any smell at all. I have had it for several years now.
Good luck

Hey Boan,

I think maybe you meant to post this in the thread I started about the holding tank sender repair?

Yes, that would work as well, more than one way to skin this cat! I don't need to pull my holding tank though, just needed to get the gauge working again.

I also changed my holding tank vent for a much larger vent under the anchor locker about two years ago. It has helped tremendously with the odor issues.

Mainship 400 vs 390 performance

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