Mainship 390 bow and stern thrusters

[Todd U]

Greetings All,
My wife and I are the proud new owners of a Mainship 390. While docking last weekend in a very strong current it was necessary to extensively rely on her bow thruster to come into our slip. After maybe 10 to 15 seconds of continuous use the thruster stopped working. That distinctive "growl" became merely a humming sound. After a short cooling off period (maybe 1 minute) it began working fine once again.
Can anyone tell me if this is a safety or disconnect feature of the Mainship thrusters? Has anyone had a similar experience? Thank you

 

[Comodave]

It probably has a thermal cutout. I installed a stern thruster in our last boat and it had a thermal cutout but it would run about 3 minutes before shutting down. Actually I never had it do a thermal shutdown. I would check the voltage when it is running. Also clean all the connections and make sure they are good and tight. Sounds like low voltage causing the thruster to heat up.

 

[sailorskip]

I had a similar situation. The battery bank was shot. Replacing the batteries fixed the problem.

 

[Arc]

They will not time out in 15 sec. most are good for 2 minute plus. Most likely the battery voltage dropped. Then later recovered for a bit. Hot connections may also do it

 

[Cartouche]

Greetings All,
My wife and I are the proud new owners of a Mainship 390. While docking last weekend in a very strong current it was necessary to extensively rely on her bow thruster to come into our slip. After maybe 10 to 15 seconds of continuous use the thruster stopped working. That distinctive "growl" became merely a humming sound. After a short cooling off period (maybe 1 minute) it began working fine once again.
Can anyone tell me if this is a safety or disconnect feature of the Mainship thrusters? Has anyone had a similar experience? Thank you

Definitely your battery bank or alternator, if it came back probably batteries. my Garmin MFD and our VHF's both have volt meters and always go off when I am using the thrusters, but I have never had the thruster not work, it probably is your batteries, try it at the dock, with no motor or shore power connected and watch the guage on the DC Panel and see how quick the voltage comes back - it should be instantaneous.

 

[DrissZougari]

My MS390 had a dedicated battery/Charger under the bed next to bow thruster. the thruster battery is only charged by the charger (at the dock or with the Genny. in this setup, I have run into the situation because I had a weak battery and it discharged really fast. Since my boat had the original battery cables running from under the bed to the aft area where all my batteries are, I have connect the Thruster battery to the forward end and aft the start battery switch. This way the thruster battery is charged when the engine as well (old thruster charger was eliminated). I have not had that specific issue since and I have also learned not to use the thruster a lot.
Good luck

 

[Cartouche]

My MS390 had a dedicated battery/Charger under the bed next to bow thruster. the thruster battery is only charged by the charger (at the dock or with the Genny. in this setup, I have run into the situation because I had a weak battery and it discharged really fast. Since my boat had the original battery cables running from under the bed to the aft area where all my batteries are, I have connect the Thruster battery to the forward end and aft the start battery switch. This way the thruster battery is charged when the engine as well (old thruster charger was eliminated). I have not had that specific issue since and I have also learned not to use the thruster a lot.
Good luck

We did the same thing when I installed a stern thruster this spring, after using it we turn on the Generator for about 15 minuets and it is fully charged for the next time, and when plugged in it is being charged by the separate charger, a side benefit is the new charger is a 3 bank unit - I have 2 batteries for stern thruster and we use the third bank for the generator battery

 

[Cartouche]

I am sure you have but have you checked the resevoir to ensure there is fluid in it, Only reason I mention it is when we bought our boat we found it had never been checked and was almost empty,

 

[rwidman]

I suggest finding and reading the owners manual for the particular thrusters installed on your boat. Most electric thrusters for recreational boats are not intended for continuous duty and will overheat and shut down after a certain time. They should run for way more than fifteen seconds though so you might have a battery or cable problem.

You might find it better yo use your thrusters in short bursts. Get the bow or stern moving and let it coast with the thruster switched off. Turn it back on if necessary for another burst of power.

It's best to think of the thrusters as "helpers", not the same as your main engine. The thrusters aren't really meant to move your boat sideways through the water.

 

[Shrew]

The thrusters aren't really meant to move your boat sideways through the water.

Yes, that is literally what they were designed to do......however, electric thrusters were simply not designed to do it at any sort of speed, or for long distances or durations.

Hydraulic thrusters were designed for heavy, 'continuous' duty work.

 

[backinblue]

Yes, that is literally what they were designed to do......however, electric thrusters were simply not designed to do it at any sort of speed, or for long distances or durations.

Hydraulic thrusters were designed for heavy, 'continuous' duty work.

I respectfully disagree and agree with Rwidman. Yes your thrusters will move your boat sideways, but that's not how you should be using them. My home dock is on a river with strong side currents at times. I would often be in trouble w/o thrusters, but I use them to help point the bow or stern in the right direction while docking, not to push the boat sideways. Normally it's not more than a couple second burst of 1 or the other. I doubt I've ever used one for 15 sec. When the conditions are not too severe, I practice using no thrusters. It's not as simple, but can be done. Also, consider the wear and tear on the thrusters and batteries if you intend to run them for long periods every time you dock.

 

[Seevee]

Agree on the comments that the trusted was likely over heater or batteries drawn down too much.


When I use the thrusters on my old MS400 you could watch the voltage drop, and was below 12v in just a few seconds. So, intermittent use worked, and it worked well. The are only to help position the boat a bit...and unlikely they'll move the boat sideways with much more that 8 to 10 kt wind or the equivalent current. However, to position the bow a bit, they work very well. The stern isn't as effective, but works great in backing into a slip.



Now my thrusters on the 400 were off the house battery... not the very best set up. However, it worked just fine and never an issue.



On my new 430, the stern thruster has its own battery bank... much more powerful.

 

[backinblue]

Agree on the comments that the trusted was likely over heater or batteries drawn down too much.


When I use the thrusters on my old MS400 you could watch the voltage drop, and was below 12v in just a few seconds. So, intermittent use worked, and it worked well. The are only to help position the boat a bit...and unlikely they'll move the boat sideways with much more that 8 to 10 kt wind or the equivalent current. However, to position the bow a bit, they work very well. The stern isn't as effective, but works great in backing into a slip.



Now my thrusters on the 400 were off the house battery... not the very best set up. However, it worked just fine and never an issue.



On my new 430, the stern thruster has its own battery bank... much more powerful.

Sounds like the trend is to increase usage of thrusters as boats get newer.

 

[Hawkshaw1]

I am sure you have but have you checked the resevoir to ensure there is fluid in it, Only reason I mention it is when we bought our boat we found it had never been checked and was almost empty,

Ed gave me the same advice when I bought our 390 and mine was just slightly low but it was great to see where it was and look at. It's under the front cabin mattress.

Hawk

 

[Hawkshaw1]

I do not understand why the battery that powers the thruster isn't charged by the main engine alternator. I don't see any reason for that. I am not sure how to wire it so that it can be but I am going to explore it.

Hawk

 

[Comodave]

I do not understand why the battery that powers the thruster isn't charged by the main engine alternator. I don't see any reason for that. I am not sure how to wire it so that it can be but I am going to explore it.

Hawk

I installed a stern thruster on our last boat. It had its own dedicated battery with a 15 amp 120 volt charger. I didn’t charge the thruster battery when we were underway and never saw the need for that to happen. We never ran the battery down by using the thruster. Now maybe if you only anchor out and never run the genset then there might be a need to charge it from the engines.

 

[Hawkshaw1]

My thruster battery also runs my inverter. The inverter runs the microwave and the coffee maker. It’s not an issue now but if we cruised on longer trips it might be.

Hawk

 

[live2fish]

We had a 2008 Mainship 34 Trawler with electric bow and stern thrusters. Most electric thrusters are designed to run no more than six continuous minutes. How long they run before the cut-off occurs depends on the battery condition, cleanliness of the thruster blades and tunnel, the ventilation in the compartment where the thruster is located and if the wiring is properly gauged. Bow thrusters tend to be larger and should have a dedicated battery. That was the arrangement on our Mainship. Thruster batteries can be charged by either the engine alternator or by a charger that you can operate by running your genset when you know you will be depending on the thruster. Our Ocean Alexander has bow and stern thrusters and the bow thruster, being the larger has a dedicated battery and charger.

 

[Bacchus]

Originally MS installed diode isolators for splitting alt charge to thruster bank and start/house. I felt the diodes were enough of a V drop to warrant replacement with a better technology. For a full write up & schematics see my Bacchus website- Projects - Charging System Mods

Since making the mods I decided to also move my engine start to the thruster bank leaving the house bank as a pure house.
That start move was actually fairly easy and resulted in a wiring run about half the distance as from the house bank thus reducing the V drop under hi smp starting loads.

I also added a Balmar Smart Gauge to better monitor my house and start/ thruster banks and now very pleased with the set up and operation, which I feel is a significant improvement from the MS factory installation.

 

[backinblue]

My MS 355 Pilot ( esentially a MS 31) has 2 start batteries and 2 house batteries. It has bow and stern thrusters that came standard at the time. Both are wired to the Engine start bank, no dedicated batteries. All 4 batteries were group 24 from the factory, I upgrade the house baterries to group 31. The engine starts immediately so very little draw at all on the start batteries. However, upon starting, the engine heaters hold the voltage down below 12V till they turn off after a few minutes when the engine warms up. That's often the time I may be using thrusters leaving the dock. But my thruster use is measured in seconds, not minutes, so all seems to work fine. My generator is also wired to the start bank which seems ok because the start bank is always at full charge when the Engine is turned off. The house bank will draw down overnight for refrigeration and lighting, etc, but the larger batteries make a big difference and are at 12V+ in the morning.

 

[Bacchus]

Backinblue
GP 24s seem small for B& S thrusters... maybe OK for start. You might fo some V checks to document what the V drop is for various times of thruster use.
Even if "normal" thruster use is very short you may be surprised one day by an u expected current or gust that you might wish you had more than minimal thrust.
One such occurrence sticks in my mind when approaching a marina fuel dock and and encountered an unexpected current eddy that was pushing me into rock rip rap. My thrusters saved me but it was an attention getter for sure.

 

[bethlowrie]

There is typically a thermal switch that trips the thrusters off to prevent over heating. Each time it trips it gets weaker, meaning you get less runtime. Whenever we have a time out we replace the switch. Strong batteries fully charged and fresh thermal switches will give optimal performance from the motors. Might want to check that the blades are clean as well.

 

[backinblue]

Backinblue
GP 24s seem small for B& S thrusters... maybe OK for start. You might fo some V checks to document what the V drop is for various times of thruster use.
Even if "normal" thruster use is very short you may be surprised one day by an u expected current or gust that you might wish you had more than minimal thrust.
One such occurrence sticks in my mind when approaching a marina fuel dock and and encountered an unexpected current eddy that was pushing me into rock rip rap. My thrusters saved me but it was an attention getter for sure.

Thanks Bacchus. They are fairly new batteries, maybe when I replace them I will go larger. I'll keep an eye on the voltage, usually my attention is elsewhere, but I'll take a look.

 

[Nepidae]

Mainship Thrusters

This is a good example of why not to rely on thrusters.

Today it's a bad or under charged battery, thermocoupler & tomorrow it's the motor or corroded blades.

People with thrusters use them all the time and lose the ability to pilot without them. In my mind, bad practice.

I say that because when you are traveling down a fairway and using thrusters to get in the slip and they stop working and the pilot doesn't know what to do, he/she hits my boat.

BTW, doubt that the thruster was manufactured by Mainship. You may want to chase down who's the manufacturer as you undoubtedly will need parts at sometime in the future. Usually a maintenance headache.

 

[Bacchus]

This is a good example of why not to rely on thrusters.



Today it's a bad or under charged battery, thermocoupler & tomorrow it's the motor or corroded blades.



People with thrusters use them all the time and lose the ability to pilot without them. In my mind, bad practice.



I say that because when you are traveling down a fairway and using thrusters to get in the slip and they stop working and the pilot doesn't know what to do, he/she hits my boat.



BTW, doubt that the thruster was manufactured by Mainship. You may want to chase down who's the manufacturer as you undoubtedly will need parts at sometime in the future. Usually a maintenance headache.

I hear the argument that those with thrusters should not use them as you don't know when they will quit.
Why don't those with twins preach the same sentiment... you better not dock with your twins as you will never know when you don't have that luxury so you better operate only on only one engine at a time.

I get the idea of practice and be prepared for the unexpected but it seems the negative sentiment is primarily the mucho macho type that "don't have and don't need those darn thrusters and nobody should rely on or use them"

If you don't do any PM beware anything you operate can quit at anytime... and when you least expect it.

 

[backinblue]

Not sure I understand the point. I love having thrusters but also practice manuevering w/o them. They are a great feature and make boating easier. Much like having a GPS instead of paper charts. Should we all give up our electronics because they could potentially fail some day?

BTW thursters are Side-Power / Sleipner. I may be wrong but I don't know of any boat builder that designs their own thrusters.

 

[Comodave]

I have taught boat handling for 30 years with the CG Auxiliary including testing people for boat crew and coxswain. We are putting thrusters on our new boat so that my wife will not need to go on the bow to handle dock lines and we are getting older. Older means not as strong and more unsteady. If having thrusters will lengthen our boating life then there isn’t anything wrong with thrusters. It does tend to irk me when people say just learn how to handle your boat. Well I know how to handle the boat but you can’t overcome the age thing.

 

[backinblue]

Thanks Comodave. Well-said. Many modern devices make boating easier. You can use them and enjoy them w/o being 100% dependent on them. You don't need much more than a chart and a compass to go boating, but who wants to give up their GPS, Autopilot, Thrusters, Windlass, etc, just because they can possibly fail some day. I like Bacchus' example, how many people with twin engines practice docking with one?

 

[Bacchus]

Dave
Well said... maybe better than my response. Its just a pet peave or hot button when the naysayers preach!

I look at it the same way if it makes life easier and allows us to boat longer I'm all for it. Thats why we own the boat we do... to keep us in the game.

I added a wireless remote so I can use the thrusters anywhere anytime... I guess that is sacrilege to the naysayers... another failure point Oh no!

 

[Comodave]

Everything can fail, you just deal with it when it fails and find a work around.