Bow Thruster vs Stern Thruster

Just had the boat hauled and bottom cleaned. While out of the water I discussed installation of bow thruster. Cost est about $10k. My boat has a single Lehman 120 and all the poor maunverability that comes with it. There are a couple of trawlers in our marina that have stern thrusters rather than bow thrusters. Does anyone have experience with thrusters and advice as to which is best. As further info boat backs to starboard.

Bow thrusters are much more commonly offered compared to stern thrusters. One's propeller and rudder provides some control for the stern. Stands to reason a bow thruster would have higher priority than a stern one.

Find my Coot's bow thruster very handy.

Bow Thruster

Thanks, any recommendations on best make for after market bow thruster.

My experience here - Bowthruster

Might not suit you, but you should be aware of what you are paying a lot of money for.

Mike

You already have a stern thruster-- the prop and rudder. So if you feel you need a thruster the bow would be the thing to get in my opinion. Even with a twin a bow thruster can come in handy because it lets you do something you can't do with either a single or a twin, and that is to move the bow straight sideways while leaving the stern where it is.

Bow thruster

Thanks for your responses. Stern maneuverability to porn with prop and rudder is pretty difficult with this boat. In any case agree bow thruster makes most sense.

Cost quoted from yard in Sausalito rated at $108 PH labor plus motor & parts etc... Far beyond my skill level but sounds like a good idea to shop around.

Thanks!

Not sure why it should be any harder to move the stern to port with the prop and rudder than to starboard. Prop walk has an influence but unless your boat has a very small rudder with very limited travel it should be able to easily overcome the prop walk influence. If you're talking about moving the stern when the boat is stationary in the water, try using more power to get the stern moving.

A lot of boaters, including me until a year or two ago, tend to leave their power at idle when maneuvering into and out of slips, up to a dock etc. But I finally watched enough tugs, lobsterboats, and fishboats maneuver to realize that power is every bit as helpful a tool as the wheel and the shifter(s). So now I use power, or bursts of power, all the time-- sometimes a lot of power momentarily--- and it has greatly improved both the speed and accuracy of putting the boat where I want it.

Curt R said:

Thanks, any recommendations on best make for after market bow thruster.

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A bowthruster is what you need and there is a used one for sale on the Forum right now for $1250. Check out the classifieds.

I would echo everyone else and say go for the bow thruster. I would add one thing though, if possible on your boat, I would go for hydraulic over electric. Electric thrusters are more tempramental and have limits on how long you can run them. We have hydraulic and would not have anything else.

THD said:

I would echo everyone else and say go for the bow thruster. I would add one thing though, if possible on your boat, I would go for hydraulic over electric. Electric thrusters are more tempramental and have limits on how long you can run them. We have hydraulic and would not have anything else.

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Haven't ever used my bow thruster for more than several seconds at a time. I presume hydraulic is best, but electric has served me well.

It will, as long as it's big enough. I got Wesmar to spec one for my boat, then went to the next largest size. It's a 24 volt system and has never let me down. Don't go too small because it's better to have too much power than too little.

Wesmar now makes a line of continuous duty electrics, which is what I'd buy if I were getting one now. They will run just like hydraulics, forever. Well, until the battery runs down!

We only have a stern thruster, and while I would like a bow thruster too, stern only has treated us well. It's way cheaper to install too. Our is hydraulic with an endless run time. For now, it's fine and I could go forever with just a stern. It's really about preference. TBH, we have never had a bow thruster, so we don't know what we've been missing. I'm sure that a boat in our future will have a bow thruster, but if it doesn't have a stern, we'll add one.

. Our is hydraulic with an endless run time.

One secret to success.

BE sure to read Da Book before you purchase an electric unit to see what the run/off time is.

Some (cheapos) have a very limited run and a very long cooling requirement.

Our little single engine boat came with both bow and stern thrusters. Don't use them very much as we don't have to maneuver around in marinas, but when we do use them I actually find the stern thruster a bit more useful.

Curt said:
"Just had the boat hauled and bottom cleaned. While out of the water I discussed installation of bow thruster. Cost est about $10k."

$10K, all in, may be a bit optimistic. My 11hp Lewmar with batteries, switches, inverter, redo flooring, labor etc was easily 2X $10K.

Our boat came with both bow and stern thrusters. Didn't think much of them before I had them but with the Admiral and I being the only ones on board having them is a real advantage when docking in tight areas. The admiral is more comfortable as she has little to no experience with boating.

I would suggest bow thruster. I believe some people will go with a stern thruster over a bow due to installation cost, with the stern being much cheaper than the bow. Electric would also be my choice over hydraulic. They are much quieter to operate and you don't have to change filters.

As for installation costs, I think on average you are looking at the 10-12K range for a bow depending on the cost to install. Every boat is different and as pointed out there are some boats that as a result of the design will cost more.

With regards to run time. Generally speaking I have never run my units longer than a few seconds at a time. On a rare situation I have run for up to 1 minute. This was trying to overcome a beam wind walking the boat to the dock.

sunchaser said:

Curt said:
"Just had the boat hauled and bottom cleaned. While out of the water I discussed installation of bow thruster. Cost est about $10k."

$10K, all in, may be a bit optimistic. My 11hp Lewmar with batteries, switches, inverter, redo flooring, labor etc was easily 2X $10K.

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Why would you need an inverter to install a bow thruster?

Marin said:

Not sure why it should be any harder to move the stern to port with the prop and rudder than to starboard. Prop walk has an influence but unless your boat has a very small rudder with very limited travel it should be able to easily overcome the prop walk influence. If you're talking about moving the stern when the boat is stationary in the water, try using more power to get the stern moving.

A lot of boaters, including me until a year or two ago, tend to leave their power at idle when maneuvering into and out of slips, up to a dock etc. But I finally watched enough tugs, lobsterboats, and fishboats maneuver to realize that power is every bit as helpful a tool as the wheel and the shifter(s). So now I use power, or bursts of power, all the time-- sometimes a lot of power momentarily--- and it has greatly improved both the speed and accuracy of putting the boat where I want it.

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Well said. Low speed maneuvering requires judicious use of prop wash against the rudder, and that requires power. It took me about 5 years to figure it out, but once I did, turning a 12 ton full keel sailboat in her own length using forward and reverse prop wash against a big rudder was easy to do. When the rudder is small, more power is required, so it might behoove the OP to look into whatever mods could be made to the rudder to increase its size and effectiveness. Perhaps articulation is an option?

That said, thrusters are a blessing, especially for those boats around me in the line of fire.

GonzoF1 said:

We only have a stern thruster, and while I would like a bow thruster too, stern only has treated us well. It's way cheaper to install too. Our is hydraulic with an endless run time. For now, it's fine and I could go forever with just a stern. It's really about preference. TBH, we have never had a bow thruster, so we don't know what we've been missing. I'm sure that a boat in our future will have a bow thruster, but if it doesn't have a stern, we'll add one.

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We also have a 'Stern Thruster'. It allows you the finite maneuverability that is necessary in tight marinas and heavy currents. Simple math, will you get the $12K(bow thruster) from your boat when you sell it? Do you care?

My father has a bow thruster on his 34' CHB, I have driven both and find that they both equally achieve the intended goal. Finite movement. The rudder does NOT give you finite movement. As you know, the rudder is sloppy when in tight spots.

Good luck to the OP. Look up 'Side Shift' Stern thrusters on this forum for a North American made stern thruster that is pretty easy to install and performs excellent (made in Canada).

Ron said:
"Why would you need an inverter to install a bow thruster?"

Boat is 12V and thruster motor is 24V

Papa Charlie said:

Electric would also be my choice over hydraulic. They are much quieter to operate and you don't have to change filters.

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Hmmm.... the electric thrusters I hear being used sound like rocks in a giant cuisinart. Absolutely horrible sounding things and you can hear them all over the marina. In fact I think their noise is part of the stigma that seems to be attached to using a bow thruster. It's like shouting to the world, "Look at me, I don't know how to maneuver a boat properly!"

I think a thruster is geat tool if you have one. The single-engine GB36 we chartered had one and it came in very handy on a number of occasions, particularly as we were new to this kind of boat and boating. So other than the people who use them to steer their boats as a matter of course (like a car) even in open water, I don't belittle having or using a thruster.

But I would have thought that the manufacturers of electric bow thrusters would have by now figured out a way to make them quiet other than the sound of the water being moved. I have no idea why they are so irritatingly noisy--- it's just an electric motor so I assume the grinding sound is the gearbox. The few hydraulic ones I've heard don't seem to make any mechanical sound at all.

I would give my left nut for a bow thruster.

Stern thruster....not so much.

alormaria said:

I would give my left nut for a bow thruster.
Stern thruster....not so much.

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Even with a twin there have been many times I wished I could move the bow sideways one way or the other and leave the stern where it was. However I don't know that I've ever wished I could move the stern straight sideways and left the bow where it was. But I can certainly envision situations where one would want to do this.

I have watched boats with stern thrusters only come into the docks in the marine parks on occasion. Unless the wind or current is setting them onto the dock, it seems that while they have no problem in getting the stern up against the dock, there is still a mad scramble to get someone on the dock to catch the bow line because the bow still drifts away, sometimes quite rapidly depending on how hard the stern hit the dock.

The boats with bow thrusters always do quite well in this respect, assuming the helmsman knows what he's doing. They angle the boat in by the bow, then use the prop(s) and rudder(s) to move the stern in, and the bow thruster to hold the bow in since a boat will pivot to a degree with the application of rudder and thrust so the bow will want to swing out as the rudder moves the stern in.

This is the situation we encounter the most in which it would be nice to have a bow thruster. We've always been able to deal with it by getting a spring line to the dock right away but there is certainly an appeal to eliminating the fast line handling by the use of a toggle switch.

So my conclusion is that if money is not a limiting factor a bow thruster is a much more useful and versatile tool. Not that a stern thruster isn't a help. But if you can only have one or the other, outside of its lower cost I do not see nearly as much overall value in a stern thruster as a bow thruster.

And while the notion of getting the cost of improvements to a boat back when the boat is sold is a pipe dream, I think a bow thruster adds more appeal to a boat when it's for sale than a stern thruster, unless the boat has both.

Curt R said:

Just had the boat hauled and bottom cleaned. While out of the water I discussed installation of bow thruster. Cost est about $10k. My boat has a single Lehman 120 and all the poor maunverability that comes with it. There are a couple of trawlers in our marina that have stern thrusters rather than bow thrusters. Does anyone have experience with thrusters and advice as to which is best. As further info boat backs to starboard.

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While not familiar with your vessel i do have extensive small boat experiance on a small budget. I learned with a single one plans his approach very carefully then uses sudent bursts of power to keep on course. With a neavy underpowered boat like most trawlers are a short burst of fuel throttle won't move your boat much but it will move it. Beginning boaters are afraid to hit the throttle at dockside and tend to just do things ta close to idle speed. Just be sure to take into consideration not only the wind direction but the current. With practice my money is on you not needed a thruster. Experiment when at the dock on a calm day to learn.
10k is too much. How much does the bow thruster itself cost without the labor?

Not having experiance with trawlers only planning hulls my experiance may not be entirely valad

Thanks for the link Sceptic, I have been thinking of doing an instalation myself. I just don't think it will be that hard and your experience seems to bears that out.

My boat had a bow thruster on it when we bought it, and I added a stern thruster. The stern thruster allows us to do things like move sideways into a tight spot, do a 180 quickly or easily back down a fairway with inches between us and the boats on each side. I love the stern thruster, but if I was choosing one over the other I would pick a bow thruster.

Both thrusters are made by Vetus. Our old bow thruster matched Marin's description. It sounded like we were crushing rocks. The stern thruster is very quiet. The blades have been redesigned by Vetus to be quieter and more efficient at moving water.

I changed the motor and blades in the bow thruster to the new design. It is still noisier than the stern thruster, but is significantly quieter than it was.
Lyle

My boat has a bow thruster and it's a big help in tight situations.. "Back and fill" is fine when you have the room and the time, but it's a big help to have other tools (thruster) as well.

The sound of the thruster doesn't bother me at all.

Marin said:

Not sure why it should be any harder to move the stern to port with the prop and rudder than to starboard. Prop walk has an influence but unless your boat has a very small rudder with very limited travel it should be able to easily overcome the prop walk influence. If you're talking about moving the stern when the boat is stationary in the water, try using more power to get the stern moving.

A lot of boaters, including me until a year or two ago, tend to leave their power at idle when maneuvering into and out of slips, up to a dock etc. But I finally watched enough tugs, lobsterboats, and fishboats maneuver to realize that power is every bit as helpful a tool as the wheel and the shifter(s). So now I use power, or bursts of power, all the time-- sometimes a lot of power momentarily--- and it has greatly improved both the speed and accuracy of putting the boat where I want it.

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Thanks for your responses. I have always been concerned that the helm won't respond to rear port. I will try more power. I wonder now if the rudder and prop are correctly proportionate. Attached is a pic took last week when the boat was hauled.

Great Laker has both a bow (factory installed) and stern (previous owner installed) thruster. I use both together in turning the boat in a narrow fairway, lets say for entering a slip. I use the bow thruster mostly for keeping the bow near a dock after an approach and during tie up. I use the stern thruster mostly for steering the stern while backing into a slip.

I agree that the bow thruster makes the most sense if you have to choose between one or the other, as you can control the stern with the rudder/prop. However, backing down a channel or into a slip is really easy with the stern thruster. Since the stern thruster is much less expensive to add to a boat, there is a good argument to pick that one if you can only afford one.

READY2GO said:

Thanks for the link Sceptic, I have been thinking of doing an instalation myself. I just don't think it will be that hard and your experience seems to bears that out.

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I did my own bow thruster install as well. I stumbled upon a great deal ($750)for a new in box Sidepower SP55 and 7" ID tube that I bought from a guy whose boat building dream had died. I upgraded it with all of the kits I could purchase so that is essentially a SE60 model now.

I estimate (I'm not at home now) that I spent ~ $1,200 on supplies to install. I used top quality, and bought wisely, but it adds up.

The boat was conveniently located at my house which made it easier.

I read all the manufacturers literature out there and many websites (like sceptics) before proceeding. Regardless of the brand you purchase, or even if you have someone else install, I would recommend downloading the manuals of of the Sidepower/Imtra site as they have very detailed installation instructions. Tube location and fairing are very important for the increase in efficiency and decreasing the noise that Marin alludes to.

I used West System epoxy and lots of biaxial cloth. Spent a lot of time doing the proper step tapers so as not to create any sharp or lumpy transitions which cause stress risers.

The electrical was straight forward. All Blue Seas and oversized cable.

I used lasers and rare earth magnets to help with my location layout. Measure a bazillion times and cut once.

I made my own cut out tool. ( No 70's Defever hull thickness here, only 9/16"). Leave tabs to saw out later. Remember you have to cut the other side!

Ensure you radius the tube for smooth flow.

I put an eyebrow on the front of mine so there is no flow noise underway.