Maneuvering a Single Screw with a Bow Thruster

[slowandsteady]

After taking possession of a Mainship 34 III a few weeks ago, I experienced a little "difficulty" docking in the marina that I call home, tide going out and a stiff breeze in the same direction. Luckily, there were few boats or people around so I got out of the situation unscathed after three tries. Not maneuvering a boat in quite a few years (that boat was a twin screw in a very protected marina) I contributed my difficulty to being rusty and a single screw boat. I've read that I shouldn't become reliant on the bow thruster so I practice backing down the alley between slips with just the rudder and transmission, getting used to the prop walk, etc. I became confident since that first time and thought I had it licked until this past weekend. This time the wind was from the opposite direction and I couldn't get my bow into the wind soon enough and, well, before I knew it, I was in trouble. The awesome group of people on my dock came to my rescue and bailed me out, with good humor, grace and went out of their way not to make me feel like an idiot. One of my problems was after a few short blasts (at least I THOUGHT they were short) on my thruster, it quit on me. I haven't tried to see if it works since then but my questions are as follows:
Is there a maximum number of continuous seconds that I can use it before it stops working?
Is there some kind of circuit/overload protection that makes it stop working?
Was it possible I killed the battery? There is one battery for it under the v berth and there is a small trickle charger wired in that I believe works on 110 volt at shore power. When I eventually wire in the anchor windlass, they will both share the same battery. The PO left all the wiring and a solar panel and controller to charge that battery. I think that will be enough to keep the battery charged while not on shore power. Should I consider wiring it differently so that it charges while underway from the main engine/alternator? Or should a different set of batteries power it (starting batteries or house batteries)?
As I stated, I know I shouldn't rely on the the thruster, but I sure could have used it the other day and it just wasn't there for me.

 

[jwnall]

There was a thread on this not too awfully long ago. I do not have a thruster (twins), but my recollection is that quite a few people were saying that only short bursts on the thruster can be done without it overheating. Lots of good advice was given on the problem.

 

[High Wire]

Is there a maximum number of continuous seconds that I can use it before it stops working?
Dependent on how much you use it.
Is there some kind of circuit/overload protection that makes it stop working?
Yes, there should be thermal protection that cuts off the control circuit if the drive motor overheats.
Was it possible I killed the battery?
Yes. Depends on the size and condition of the battery. From your description either the bat is small or seriously degraded, or the thermal protection cut-out.
Should I consider wiring it differently so that it charges while underway from the main engine/alternator? Or should a different set of batteries power it (starting batteries or house batteries)?
I would consider all of these things as a system, not individual components.
QUOTE]

 

[Chrisjs]

You do not state the size of the single battery but be aware that thrusters consume a lot of amps -typically 300amps plus!!! Your problem is quite likely to be that your battery is too small, or on its last legs. If you plan to add a windlass to the same battery, that also draws a good amount of amps. Our bow thruster is powered by 2x4D dedicated batteries with their own charger (110V). Windlass (88lb anchor with 3/8 chain) is powered from house batteries (4 x 8D) and works best with engine running (usually the case regardless!!). Suggest you consider upgrading battery bank.
The only time we had a problem with the thruster cutting out, it turned out to be time to replace batteries!!

 

[ranger58sb]

Your avatar looks like the Mainship III we had. Last I checked, that one's in NJ.

We didn't have the luxury of a thruster, so can't speak to that.

We got pretty good with spring lines, though. There's almost always a way to use a line to warp around something or into a slip or alongside or whatever. Assuming you have one good crew aboard...

-Chris

 

[jleonard]

I ran an old single screw Mainship for 14 years without a thruster. I had a slip with 4 inches total clearance and after a few years never had a problem.
This is what I learned about single screw handling and I hope it helps you....
1) Practise doing some backing and filling using short bursts of power to make the boat move. This will get the boat to turn against the wind most times in a short distance.
2) Oonce I had the ever so slightest feeling I blew the approach...I would turn around and try again from the top. It's rare you can recover (without the help of the neighbors). Usually its a matter of thinking the wind is a "two slip wind" when really its a "three slip wind", meaning that's how far ahead you need to start your turn.
3) The boat only does one thing (ie backs to port). Learn how to use that to your advantage.

 

[LarryM]

Usually its a matter of thinking the wind is a "two slip wind" when really its a "three slip wind", meaning that's how far ahead you need to start your turn.
3) The boat only does one thing (ie backs to port). Learn how to use that to your advantage.

Hands down, the best description I have ever heard - "two slip wind" and "three slip wind" - adding that to my nautical vocabulary immediately.

Larry
M/V Boomarang

 

[Ski in NC]

Some thrusters have a pause between pushing left and right. Can freak you out when it does not work, just give it a couple sec and it should begin working.

Just sit at the dock and hold thruster on. Time how long it runs before it stops. If it gradually winds down, your battery is pooped or discharged or too small. If it stops suddenly, its thermal protection kicked in.

You need to know how long it will run.

Also, mine (sidepower) has the stupid need to hit two buttons to wake it up. It times out after like five minutes. Sometimes it seems like the timeout feature kicks in even if I had used it within the 5min. So have to hit the two stupid buttons again.

Maybe that is what happened to the op.

And no shame rubbing on things with a single screw. I do it often and consider myself reasonably skilled with a single.

 

[ranger58sb]

Usually its a matter of thinking the wind is a "two slip wind" when really its a "three slip wind", meaning that's how far ahead you need to start your turn.

3) The boat only does one thing (ie backs to port). Learn how to use that to your advantage.

Good one

I could get ours to back straight, but only over a longer distance and with a bit of way on. Once under control, not bad... but usualy to fast at that point to be approaching docks.

And no shame rubbing on things with a single screw. I do it often and consider myself reasonably skilled with a single.

Yep, I'm a big fan of RUB rails.

-Chris

 

[markpierce]

...
3) The boat only does one thing (ie backs to port). ,,,

With a "left-turning" propeller, the boat will back to starboard; a "right-turning" propeller will back to port.

 

[waterfront]

I had exactly the same trouble when I first bought my Present 35. It seemed that every time I left the slip, went somewhere and used the thruster, then came back the thruster would crap out when I tried to get back in the slip. The problem was that the battery was only being charged when I was on shore power. I added a battery isolater and ran a wire to the thruster battery so it was being charged by the main engine alternator while underway. Problem solved, for me at least.

 

[healhustler]

Slow&Steady: My old vetus bow thruster initially cut out pretty early from time to time. Of course, new 8D batteries helped a lot, but there was too much resistance in the cables to really take advantage of the new batteries, moving them closer to the thruster really helped, but the addition of proper sized cables seemed to stop the cut-out altogether. I've tested each direction for a half-minute without issues. These old thrusters want plenty of juice. If you give it to them heavy and fast, they seem happy.

 

[Boydski]

This will make you guys laugh! When I bought Sea Eagle, she was my first single screw boat and for the first six months, EVERY time I backed out of a slip, she behaved differently. Sometimes, she would back to the left (left hand propeller), sometimes she'd back to the right, sometimes she'd do both, starting one way then going the other. It had me really perplexed and missing my twin engines!

Eventually I figured out that many days I was forgetting to turn on the stabilizers and center them. So I'd have one stabilizer fin (or the other) flopped over and acting like a giant oar, pulling the boat one way or the other. DOH!!!

Now that I remember to center the stabilizers, she's as predictable as a peach.

I'm guessing slowandsteady will get the hard-over rudder and giving her some throttle to make her turn with just a little bit of practice. It won't take him six months to figure it out.....

 

[ranger58sb]

With a "left-turning" propeller, the boat will back to starboard; a "right-turning" propeller will back to port.

Yep, and jleonard called it correctly: prop walk moves this boat's stern to port when in reverse...

-Chris

 

[caltexflanc]

Rather than torture test the thruster and batteries (yikes!), see if you can get the brand and model number and contact the manufacturer for specs and advice.
It sounds like you are doing the right thing learning the boat without the thruster (it will not work again some day).

Perhaps there is an old single screw salt nearby (there must be there in Kingston for sure) to ride with you and practice. May likely be a sailboater, so adjustment may need to be made since sail boats usually have much bigger rudders.

Don't feel bad, it's all part of the sport; some people are naturals at it, some of us are always learning, so keep at it!

 

[Billylll]

In my Mainship 40SB I had (3) 31 series Lifeline AGMs under the forward berth. The total round trip was 8'. I ran #4/0 wiring to the batteries. In addition I have a Xantrex 40 amp smart charger on it and a pair of #2/0 wires to a BlueSea 500 amp ACR off the starboard motor. I have never run out of thruster power (VETUS). I eventually reduced the battery count to two 31 series AGM Lifelines. I also run the Good 850 Windlass off the same 31 series battery bank located under the front berth. The windlass is powered through #1/0 wiring. Overkill? Perhaps but neither system has ever let me down.
Bill

 

[Moonfish]

Hey Chuck Gould - In light of this, and now that you're "retired" (which for many of my friends means you will now become busier than you ever were before...), maybe we should make that "Taming of the Single Screw" video!

Chuck has given a popular seminar each year at the Seattle Boat Show on how to handle a single screw boat. We've talked about doing a multi-camera shoot and making an instructional video. It just might become as popular as his seminars.

 

[slowandsteady]

Update: I was at the boat last night to change the oil and ran into a guy on my dock that used to work for Hinkley with lots of single screw experience, he's also a sailboat owner. We took the Mainship out and he showed me some tricks around a bouy out on the bay. Between the replies on this thread and his short lesson, I think I've got it figured out, he was very helpful. Before we went out I dove into the bow thruster issue and discovered the positive terminal on the battery was full of that green fluffy corrosion stuff (not the technical term!) So I pulled out the battery, cleaned it all up and discovered it was a 900 CCA starting battery but it was installed in 2006! It was a little wet in the bottom of the tray also. After I cleaned it all up, I reinstalled and the thruster worked fine. I think I will have to address the way the PO set up the power for everything. I believe I would like to put the thruster and windlass on the starting batteries and set up a house bank for everything else. I like stuff simple and it is definitely not the way he set it up. Thanks to everyone for the advice on the subject, I knew I would get good feedback here.

 

[Billylll]

I think it's time for a new battery if the original is from 2006 and you have fluid leaking into the battery box.
Bill

 

[rwidman]

Rather than torture test the thruster and batteries (yikes!), see if you can get the brand and model number and contact the manufacturer for specs and advice..........!

It took fifteen posts to come to this pretty obvious recommendation!

Each brand will be different from the others.

 

[Ski in NC]

It took fifteen posts to come to this pretty obvious recommendation!

Each brand will be different from the others.

Regardless of what the manufacturer states it should do, I'd like to know what it actually will do. Especially after it reportedly failed in use. A one minute run is not a torture test.

 

[BDofMSP]

Chuck has given a popular seminar each year at the Seattle Boat Show on how to handle a single screw boat. We've talked about doing a multi-camera shoot and making an instructional video. It just might become as popular as his seminars.

If you do that, please make sure that you film on a day that has some wind! Most instructional videos that I've seen are in ideal conditions, leaving you confident but actually unprepared for the real thing.

Last year we chartered a single screw 39' houseboat in Ireland. Our training was on a beautiful day, and although I only had I/O experience previously, I felt pretty confident and did well the first day. Even backed into the slip perfectly. Well the next morning the winds were blowing at 18k and I immediately became less confident. I got to meet several other boat owners that morning as I was trying to leave the marina.

 

[healhustler]

I got to meet several other boat owners that morning as I was trying to leave the marina.

Yeah.....isn't that great that boating is such a socially stimulating hobby?! 18 knots of wind in a fairway will often bring out even the most stoic of Captains.

 

[Wxx3]

I ran an old single screw Mainship for 14 years without a thruster. I had a slip with 4 inches total clearance and after a few years never had a problem.
This is what I learned about single screw handling and I hope it helps you....
1) Practise doing some backing and filling using short bursts of power to make the boat move. This will get the boat to turn against the wind most times in a short distance.
2) Oonce I had the ever so slightest feeling I blew the approach...I would turn around and try again from the top. It's rare you can recover (without the help of the neighbors). Usually its a matter of thinking the wind is a "two slip wind" when really its a "three slip wind", meaning that's how far ahead you need to start your turn.
3) The boat only does one thing (ie backs to port). Learn how to use that to your advantage.

Thanks so much. I've been practising all year, but your advice will help me more meticulous.

 

[geoffm]

Now that I remember to center the stabilizers, she's as predictable as a peach.

I had a similar lesson involving my trim tabs, early in the ownership of my boat. I couldn't figure out why the boat would drift to one side while backing up. A fortuitously-timed column in a local boating magazine made me realize what had been happening.

So stabilizers will drift out of position when a boat is sitting at the dock?

 

[Boydski]

So stabilizers will drift out of position when a boat is sitting at the dock?

Yes, when the hydraulic pump is off (PTO), the pressure bleeds off and they will flop around at the dock.

You can see that both stabilizer fins have relaxed and "flopped" in the photo below of my boat in the slings prior to launch.

 

[Billylll]

Do we even know which thruster he has and the size of it?
Perhaps a little more information and we can make suggestions for getting the thruster to be reliable. My VETUS has never cut out and it only has a minor delay between changing directions. It's probably less than a second.
It also has a timer so I only engage the thrusters on button shortly before using it.
Bill

 

[angus99]

Yes, when the hydraulic pump is off (PTO), the pressure bleeds off and they will flop around at the dock.

You can see that both stabilizer fins have relaxed and "flopped" in the photo below of my boat in the slings prior to launch.

Strictly based on what I see on TV, I believe there are pills today that can help with that.

.

 

[slowandsteady]

I have a Sidepower thruster just like Ski in NC has with the double on button. I will be putting some grease on the battery terminals and keep an eye on it until I reconfigure my battery situation next winter.
Boydski, does it make you nervous seeing your boat so high up in the air like that? Couldn't the travel lift operator let it down 8 or 10 feet? Looks like pucker time to me.

 

[Boydski]

Boydski, does it make you nervous seeing your boat so high up in the air like that? Couldn't the travel lift operator let it down 8 or 10 feet? Looks like pucker time to me.

Actually, the real pucker time came just after they released the boat from the slings. It was fairly windy out and the yard crew lost control of the boat (the bow was just about to crash into the concrete on the left side of the picture). I wasn't supposed to be on the dock, but had to jump in, grab a line and wrap it around a piling to arrest the bow swing.

The boat being so high in the air is not ideal, but the large tides (14'+) often mean it will be a long way up in the air.