Bow Thruster vs Stern Thruster

[arcadia]

Upvote

 

[Comodave]

I’m following with interest. I’ve got the same Hull in a Meridian 490. Do have a bow thruster and had considered stern thruster, but low on the wish list. Please keep us informed if you go ahead with the project.

Welcome aboard. I like the 490 very much. Nice boat.

 

[seighlor]

Working below decks yesterday, I looked out a port when hearing the sound of a nearby thruster. An approximately 45 foot sailboat, a contemporary design, was approaching the T-head on the dock opposite where I was tied up. Conditions were benign. Hardly a breeze and no current. After a great deal of maneuvering and much use of his bow thruster, the fellow at the helm finally managed to get his boat to within about ten feet of the dock where his cute little bow ornament was able to thrown a line to the waiting dock master.

Bow thruster... stern thruster... doesn't matter if you don't have a clew as to how to handle your boat.

 

[Mako]

I'd like to buy one of those cute little bow ornaments!

 

[TemptUs]

Whether it’s buy or rent, they are one of the most costly accessories on the boat. Especially when it comes time to upgrade.

 

[O C Diver]

The Dockstar Thrusters are not like any other on the market. They are remote control and rechargeable battery operated. Both thrusters can be installed within 1/2 hour. Check out the videos at https://www.dockstarthrusters.com/

They look better than I expected, but I'd want to see what they do opposing a 25 knot wind or 2 knot current.

Ted

 

[Sharpseadog]

No one has mentioned this, but a bow thruster provides the only good way to steer a single engine inboard backing down a long narrow fairway. [emoji924]

 

[Woodland Hills]

I have 36hp of thrusters, 18 at each end, and they won’t move us sideways at 2kts. They do overcome a 25kt wind though.

 

[WayneDana2]

"I'd like to buy one of those cute little bow ornaments!"

Whether it’s buy or rent, they are one of the most costly accessories on the boat. Especially when it comes time to upgrade.

Fun though! And useful for many things other than docking. I love having my GalleyWench™ bow ornament onboard.

 

[syjos]

No one has mentioned this, but a bow thruster provides the only good way to steer a single engine inboard backing down a long narrow fairway. [emoji924]

How about backing and filling.

Sandpiper a single, will back straight and even turn slightly with the rudder if I back fast, around 4 to 6 knots.

I prefer backing and filling. Backing fast makes other boaters nervous.

 

[Irish Rambler]

Just my two cents. We've always had single engines for many reasons and when we changed our boat I 'fenced' the rudder to make it more effective. I sourced on eBay a 95kg ex shop demo thruster (our boats 42') for half the price of a new one.
Previously we had none but as age creeps ever onward we liked the idea of a thruster to ease the older muscles and ease the admirals ropework and its proved to be magic
Using prop walk we can put the boat in sideways.
One thing I would point out is to get one with a brushless motor so no carbon dust and buy one at least one size larger that the 'experts' recommend.
To control it we use a Morse control 1700 series with trim/tilt switch modified to give me single lever hand control.
Parks Masterson will supply you one at a fair price.

 

[Woodland Hills]

Does backing and filling work with a strong cross current? Sometimes you have to crab against a current with prop walk taking you the wrong way, keeping the bow over to direct the stern can be the only way to get there. That’s no more unlikely a scenario than some of the others we read here.

 

[syjos]

Does backing and filling work with a strong cross current? Sometimes you have to crab against a current with prop walk taking you the wrong way, keeping the bow over to direct the stern can be the only way to get there. That’s no more unlikely a scenario than some of the others we read here.

Backing and filling works with strong cross current and side wind. Better than using the bow thruster alone.

With strong cross current and side wind, I back fast at 4 to 6 knots, which allows me to steer the stern towards the side the wind or current is coming from with the single large rudder. The bow thruster is used to assist the rudder.

 

[Nickair]

Hydraulic stern thrusters can be operated much longer than electric motors. Stern Thrusters may be used for emergency steerage if needed. With a single engine, the stern thruster will assist in backing a straight line, countering prop walk and/or current/wind.

With twin engines, stern thruster/s allow a boat to move straight sideways using both engines and stern thruster. No bow thruster is needed. Stern thrusters are less expensive, therefore better quality hydraulic unit/s may be acquired. Stern thruster is easy to install and keep clean compared to a bow thruster.

 

[Beaverlake]

Mr Nick - thanks for your feedback. Do you have direct experience with twins and using just a stern thruster or are you (like me) engaging in speculation/theory? That’s how I ended up starting this thread - not really a bow vs stern thruster debate but essentially can a stern thruster provide sufficient benefit vs a bow thruster to warrant consideration and the resulting lower cost (twin engines, non-displacement hull). I never thought about investing any savings in using a hydraulic stern thruster so thanks for that insight.

 

[Comodave]

We have twins with a stern thruster. I put the stern thruster in a couple of years ago. It is very helpful. We use it to bump the stern to the dock by the time I can get down from the flybridge. As to hydraulic thrusters, I think they are overkill unless you already have hydraulics on board. Mine will run for 3 minutes before it gets too hot. That is a really long time. I doubt that I have run it over 10 seconds at a time.

 

[Nomad Willy]

Gordon, warning much of this is speculation.

The only times I’ve thought about a thruster is anchoring in a head wind. The wind blows my bow “downwind”. Soon I’m broadside to wind and wave (if present).
I thought a stern thruster would be the ticket to straighten the boat out. If I used my rudder it would require fwd gear and thrust. I’ve tried that. Of course I want to back down not power fwd on the rode.
So for this situation I would need a bow thruster ... I thought.
But no, the bow thruster would be pushing the bow into the wind. Whereas the stern thruster would be pushing the stern and the wind would then be aiding the boat rotating parallel to the wind.

So I’m still thinking I need a stern thruster. However I could tie my rode to a Sampson post amidships and power the anchor into the sea bottom all the while w the boat rolling some jerking on the rode. HaHa but if one left it that way one may never get the anchor back.

I’ll try the midships Sampson post first. And I don’t see a thruster as a gotta have item.

 

[Nickair]

Mr Beaverlake, I had a stern thruster on a Wooden 32 footer. I could walk the boat directly to the side. Working both engines. Transmissions, one forward and one reverse. The reverse engine needs more RPM, as you may know, to maintain no for or aft movement. This setup is nice for singlehanded easing to the side dock and parallel docking in tight places that you would have otherwise passed on. Many times I wished I had a stern thruster on our 38’ but it was in a partnership.

 

[O C Diver]

No one has mentioned this, but a bow thruster provides the only good way to steer a single engine inboard backing down a long narrow fairway. [emoji924]

See below, post #21 and #22:

I ran my boat for a few years with no bow thruster. I could manage, but once I installed it, it is SOOOOO nice to have. When I built the boat, I left a clear area in the forefoot to make it easier to install, and the install was not too difficult.

In my narrow creek, I have to back out about 100yds before it gets wide enough to spin it around. Thruster makes it easy. Just leave rudder at zero, idle in rev, steer bow with thruster. Before the thruster I had to do lots of "back and fills".

I have never felt the desire for a stern thruster. Just no need. I can kick the stern around well enough by positioning the rudder (and not a huge rudder at that) and bursts of fwd/rev/fwd/rev.

There is a fuel dock in Cape Haze, FL that requires that same technique for 40'+ boats. As you described, it's so easy, especially from my stern docking station. When the dock attendant sees me backing that way, he just shakes his head, and says,"That's just not fair ".

Ted

Ted

 

[caltexflanc]

Hydraulic stern thrusters can be operated much longer than electric motors. Stern Thrusters may be used for emergency steerage if needed. With a single engine, the stern thruster will assist in backing a straight line, countering prop walk and/or current/wind.

With twin engines, stern thruster/s allow a boat to move straight sideways using both engines and stern thruster. No bow thruster is needed. Stern thrusters are less expensive, therefore better quality hydraulic unit/s may be acquired. Stern thruster is easy to install and keep clean compared to a bow thruster.

Huh? That is simply not true. In fact, you walk a twin engine boat sideways with no thruster of any kind. And in that situation, a bow thruster brings much more to the party if available. I have direct experience with all the scenarios, and I am anything BUT the Greatest Boat Handler of All Time.

 

[rgano]

Huh? That is simply not true. In fact, you walk a twin engine boat sideways with no thruster of any kind. And in that situation, a bow thruster brings much more to the party if available. I have direct experience with all the scenarios, and I am anything BUT the Greatest Boat Handler of All Time.

From a DIW condition, a GB 42 cannot to walked, nor can a GB36 nor a Jefferson 42. I can sort of make a twin with keel "walk" to a pier with the engines if I get a bit of motion toward the pier to start with. I have done it in a four screw crew boat and in a flat bottomed landing craft. They wouldn't let me try it on a battleship (four screws) which is quite flat-bottomed. Walking a boat that will actually do it takes a lot more throttle than the usual boat owner would be comfortable with in confined areas. I have actually won a Fleet-wide shiphandling competition, but there was no walking of the destroyer.

 

[caltexflanc]

That's interesting Rich, because I, definitely not the most adept person in the world, have walked a GB 46 classic (w/BT), a GB 49 Classic and a GB 49MY sideways, or pretty much so. So the smaller GBs are different I guess? Puzzling. Dumb luck on my part? That's always a possibility.
By the way, I'll add a Mainship 430, Mainship 390, a Tollycraft 32 and a Hatteras 56MY (w/BT, and a deep keel) to the list. Wind and current conditions certainly affect the degree of difficulty to be sure. So,as I have a lot of respect for you between the years at T&T and now here, what did you see as the challenges?

 

[psneeld]

Not all twins walk sideways, especially not with wind or current from certain directions.

Some will, some won't, sometimes or not at all.

 

[boathealer]

Not all twins walk sideways, especially not with wind or current from certain directions.

Some will, some won't, sometimes or not at all.

Great Harbor N37 "walking sideways" with no bow or stern thruster. No current or wind, mind you.

https://youtu.be/V82z7IeqnIs

Engine thrust (from the MASSIVE 53hp engine each!) and rudder orientation are as below:

 

[caltexflanc]

Some will, some won't, sometimes or not at all.

Which ones?

 

[Baker]

I will say....I cheated to the very max on Sunday. We got invited to the local yacht club for brunch. And I got alongside a pier and instead going through all of the motions of getting right on it.....I simply slammed both thrusters to port and snugged right up to the dock.....guilty pleasure!!!!

 

[Comodave]

I will say....I cheated to the very max on Sunday. We got invited to the local yacht club for brunch. And I got alongside a pier and instead going through all of the motions of getting right on it.....I simply slammed both thrusters to port and snugged right up to the dock.....guilty pleasure!!!!

Nothing wrong with using thrusters, if you have them use them. Does anyone bitch about people that have joy stick steering? No, people don’t tell them not to use the joy stick and instead just learn how to drive the boat...

 

[Beaverlake]

So I have e a very generous offer from a fellow 4788 owner who is home-ported down south in Tacoma WA and who posts on another forum. I will set up some play time with him sometime “soon” (except for Sunday and today we’ve had almost constant rain some cold, some snow, and some winds). He’s on board with doing some empirical testing with our shared-design soft chine, shallow-keeled, twin engine boat that has probably middle-range wind profile. I will report on our experiences when we’re done. Maybe even try a short video or two.

 

[Nickair]

Huh? That is simply not true. In fact, you walk a twin engine boat sideways with no thruster of any kind. And in that situation, a bow thruster brings much more to the party if available. I have direct experience with all the scenarios, and I am anything BUT the Greatest Boat Handler of All Time.

I like your post and agree that a bow thruster is a more effective choice, although that is not what I was talking about. I was simply trying to point out that a much less expensive stern thruster option will assist with a twin semi-d, walking sideways. It does work well for the money invested. Not all twin boats will want to walk sideways with twin engines. Some do. I ran a military boat with twins that would go a ways then twist with in 60 seconds, so controls would all be reversed with their settings every minute or less. You could walk sideways all day. Many will not do that. A fixed gear twin 32 that did not want to walk well sideways at all. An inexpensive Stern thruster helped it to be done beautiful. Yes a bow thruster would have been better, although much more expensive on A wooden 32’. The stern thruster was the best choice there. Different boats are different.

 

[Nickair]

So I have e a very generous offer from a fellow 4788 owner who is home-ported down south in Tacoma WA and who posts on another forum. I will set up some play time with him sometime “soon” (except for Sunday and today we’ve had almost constant rain some cold, some snow, and some winds). He’s on board with doing some empirical testing with our shared-design soft chine, shallow-keeled, twin engine boat that has probably middle-range wind profile. I will report on our experiences when we’re done. Maybe even try a short video or two.

Empirical evidence helps make the best decisions.