Bow Thruster vs Stern Thruster

[syjos]

If bow and stern thrusters are unnecessary and going without them is a badge of honor, then why does every professional big yacht captain use them constantly? They have lots of skilled crew, the very latest of equipment, lots of dock hands helping them come and go and yet the thrusters are running constantly. As I sit here in Nassau typing this, a 90 footer just came in heralding it’s arrival with the grinding of bow and stern thrusters. Last week a 130 footer used it’s stern thrusters to get off the dock against an adverse current despite having 4 paid crew to spring.

Are you saying these guys take no pride in their skills? That they are unaware of how to use springs and differential thrust to maneuver?

Or perhaps professionals use the appropriate tools at hand for the job they need to do and endeavor to do it as simply and as easily as possible. Maybe having pride in your skills is not showing off and just getting the job done. At a going rate of $1000 to $1500 per foot per year, perhaps they have nothing to prove.....

At 63’ we are the smallest boat in the marina. There are 5 130 to 150 footers here tonight and last week we had a 220 footer. They all came and went to the sound of grinding thrusters. Were their captains all a bunch of low skilled no-priders?

A professional captain is being paid to drive someone else's boat. Any mishap and his professional reputation or his employment is in jeopardy. And worse case, CG displinary action or loss of license.

For the professional captain, driving the boat is a job. Sure it beats going to an office every day, slinging burgers etc. But it is still work putting up with boat owners and being the responsible one on the boat.

A professional captain usually spends more time on the water then pleasure boaters and will use every tool available to prevent issues, make his job easier and get that boat into it's slip as fast as possible so he can go home and have a beer. He certainly does not want to spend any more time than required trying a new approach or showboating.

For a pleasure boater the operative word is "pleasure". He is enjoying a hobby/lifestyle honing skills and trying different approaches to maneuvering. He is not in a hurry to get home, usually trying to spend as much time as possible on the boat.

Pleasure boaters enjoy the compliments received after a successful docking and most pleasure boaters want to be known as a good driver instead of "look out here comes bumper boat (insert name)".

Professional Skippers don't usually receive accolades when docking in difficult situations because they are expected to be skillful. When I drove other people's boats, I used every tool available.

And professional captains are not hired to drive 40' boats. If my boat was larger then 45' - 50' I would be using every aid I have.

 

[Sailor of Fortune]

Not sure about yacht captains jobs, but in commercial world, 50% of the job is running the boat.. Crew management, regulatory compliance,ships biz and dealing with the office is the rest of the deal...

 

[mvweebles]

Vast majority of boaters will have less stress about using their boats if they have a thruster(s). Although I've been a professional delivery skipper and drove a dinner cruise boat on SF Bay for a while and I've owned my boat for over 20 years, I count myself among that majority, especially as the slip I now own in Florida is not ideal. As part of my refit, I'm having a bow thruster installed and a fishtail rudder to improve ass-end maneuverability. Obviously, I'm unapologetic about doing so...

As others have said, professional skippers will use every tool available to assure a safe landing. They don't really care what anyone may think - they'll be gone in a few minutes

 

[Arc]

Whenever I dock I hit the thrusters even if I don’t need them. It makes me look cool and everyone is jealous. You know you are.

 

[syjos]

Whenever I dock I hit the thrusters even if I don’t need them. It makes me look cool and everyone is jealous. You know you are.

Exactly! And you are being honest.

Different way to showboat.

 

[Fletcher500]

Yup. Bow and stern thrusters on our Single. Love them.

 

[Beaverlake]

Talk about thread drift (pun intended)! My simple question was this: does a bow thruster bring enough extra value to justify the somewhat large cost differential between a bow thruster and a stern thruster? The feedback from those with experience seems to indicate that there is enough value in a stern thruster to forego the extra expense associated with a bow thruster. For most of the examples referencing the use of a bow thruster and twin engines I can imagine the same scenario using a stern thruster and twin engine spin in the opposite direction. Stern thruster only comments seem to support my high school physics logic.

No better or worse judgement, no thruster vs no thruster argument. A simple question of physics, fluid dynamics (water and air) and the effectiveness of the chosen tool.

My conclusion is that I will probably stay the course with no thruster(s) and rely on my boat handling and prep skills and knowledge. My motto continues to be “he who docks but backs away shall live to dock another day”. I have had occasion to make 4 or 5 passes backing into our slip or transient slips when there is a strong crosswind (we have double slips, two boats side by side with no intervening piers or pilings). I’ve done it with our Tolly 44 (bow and stern thrusters, decent forefoot) and our BL 4788 (no thrusters, shallow forefoot). The Tolly was definitely easier to maneuver in crosswind and current. I admit that I miss the extra tools when needed. But if I do take the plunge I think I’ll go stern only and put the savings into more hours on the water.

Again, thanks everyone!

 

[Andy G]

Mr Beavelake I admire your heroic determination of ensuring the thread does not drift too far from the original post.

However, some of the best threads on TF, over the years, ended up a long way from the original post. Take it as a compliment that your question has in turn spawned many other observations and questions.

So, rather than start a new post I will hijack this one, a little, if I may and pose my own question.

My IG 36' is a twin screw boat, and for various reasons I have ,like some here, been contemplating thrusters.What I am trying to determine is how do the 'bolt on' products compare in real life, to the more traditional tunel versions.

I understand there is a price differential , however that is really only one part of the conundrum. What of performance,vulnerability and reliability issues.
I must admit the idea of bolting on a thruster under the bow of the boat leaving it exposed would be a leap of faith for me. More so than bolting a stern thruster on.

I would love to hear from someone who has gone down this path and hear what they have to say.

Cheers,

Andy

 

[Comodave]

One of the members has an Exturn bow thruster. I suggest you start a new thread on Exturn bow thrusters and he will most likely chime in. BTW, he loves his.

 

[mvweebles]

One of the members has an Exturn bow thruster. I suggest you start a new thread on Exturn bow thrusters and he will most likely chime in. BTW, he loves his.

One of the things I like about my full keel displacement boat is comfort of "feeling" my way through skinny water. I'd imagine that benefit is lost with the Exturn bow thruster?

For this with barn door rudders, I've seen credible reports that a fishtail rudder modification greatly enhances close quarter maneuvers and would be a non-mechanical alternative to either a stern thruster or even an articulated rudder.

 

[psneeld]

For the external bow thruster damage...hitting a semi floater at speed I can imagine is the biggest threat.


In skinny water...1: most people would slow if really that shallow and 2: many groundings are by the stern because of keel shape.... so that depends. Of course hitting a sand bank or something hard ranks up there with hitting that big floater.


I agree with one of Teds (Slow Hand) and any others that have posted with a barn door rudder, get enough angle from it and you are almost there anyway. I can see the fishtails and articulating rudders as being much more valuable on smallish rudders....though I am sure they add effectiveness to barn doors...just suggesting moving your stops first

 

[rsn48]

For the external bow thruster damage...hitting a semi floater at speed I can imagine is the biggest threat.

Trust me I thought a lot about this before I purchased one. Where I and just about all BC coastal cruisers boat are in waters that carry logs, the worst being semi-submerged. For me it was an external thruster or none at all. The conclusion I came to was that I'd rather have the log crap up my thruster than the leg and further damage to my engine. Ditto crab trap lines. If my external thruster picks up a crab trap line and keeps it from the propellor, I'm happy.

 

[jimdavi]

Have bow and stern thrusters, although I try not to use them, ( to keep improving) they have saved me a few times. Makes the experience so much less stressful. Also great for nudging the boat over when tiring up or departing.

 

[Seevee]

Vast majority of boaters will have less stress about using their boats if they have a thruster(s). Although I've been a professional delivery skipper and drove a dinner cruise boat on SF Bay for a while and I've owned my boat for over 20 years, I count myself among that majority, especially as the slip I now own in Florida is not ideal. As part of my refit, I'm having a bow thruster installed and a fishtail rudder to improve ass-end maneuverability. Obviously, I'm unapologetic about doing so...

As others have said, professional skippers will use every tool available to assure a safe landing. They don't really care what anyone may think - they'll be gone in a few minutes

Where are you getting the fishtail rudder?

 

[Comodave]

For the external bow thruster damage...hitting a semi floater at speed I can imagine is the biggest threat.

Trust me I thought a lot about this before I purchased one. Where I and just about all BC coastal cruisers boat are in waters that carry logs, the worst being semi-submerged. For me it was an external thruster or none at all. The conclusion I came to was that I'd rather have the log crap up my thruster than the leg and further damage to my engine. Ditto crab trap lines. If my external thruster picks up a crab trap line and keeps it from the propellor, I'm happy.

I have not put one on yet, but I am thinking about it. I don’t have room for a traditional tunnel. On my boat it still wouldn’t be the lowest part of the boat because I have a pretty big keel that will be lower than the external thruster.

 

[Spinner]

When I bought Spinner (Nordic Tug 42) in 2018, she was equipped with a decent side power bow thruster. The very first thing I did was to have a stern thruster installed (CSR boatyard in Seattle did a fine job). The additional cost has been worth it! I single hand my boat 95% of the time, and the thrusters with remote allow me to get off the boat and secure lines while holding the boat right at the dock. Would love to be able to spring on and off, but there’s no way (to my knowledge) to use that technique singlehanded.

As others have noted, I believe that the thrusters really enhance the safety of my boating experience.

 

[rsn48]

At the end of the day, external thruster or not, we don't want any part of our boats hit by anything. The external thruster is just another thing you hope doesn't get hit. Just pretend your boat is one of those really large ships with the bulbous nose in front.

 

[caltexflanc]

I haven't seen the need for a stern thruster on the various twin engine boats we've run, including our high windage tub of a Hatteras. The bow thruster did come in handy when I remembered to use it, having not had one previously. If you can get a bow line out, you can get a spring line out and bring the stern right in. I could, and did single hand our boat that way. I should add we are not very adept in general (our self-imposed nickname being Mr. and Mrs. Bumble).

I can sympathize with the OP, even if you can, as we sometimes had to, slide wind the boat to the dock, the wind can blow you right off. With the spring on, you can put the helm over, the dockside engine in idle and forward, and the boat will stay in place while both or one of you take care of all the lines. Practice makes (in our case, almost) perfect.

 

[Senojev]

Stern Thruster

I added a Yachtmaster stern thruster a few years ago on my 37 Nordic Tug and have been exceptionally please with its performance. A very easy install with one large hole and two small holes - less than 8 hours including three hours installing two batteries in series for 24v and 12v to 24v charger. Since it is hull mounted it sits about 18”” below surface and thrust is exceptionally good with little surface turbulence unlike a transom mounted thruster only inches below surface. With the motor surrounded by water the thruster can be run for long periods with no overheating. They claim you can run until the batteries are flat ... 20 minutes!

 

[Jacques Burgalat]

Neeltje has SidePower 175's imbedded at both ends, and they make parallel parking and cutting doughnuts a breeze. I initially had the bow thruster installed when we took her from Fort Lauderdale to Saint Augstine and quickly realized that since her massive rudder and single 27" screw were practically useless at slow speed, just being able to push the bow around wasn't going to cut it. Hence, I had an identical stern thruster installed in Saint Augustine, and I was glad I did when I lost rudder control halfway from there to her new home on the Saint Johns river. Granted, she's a flat-bottom barge and we had minimal currents to deal with, but we still made it from Jacksonville to Palatka without a rudder.

 

[RossWilson]

My previous boat, a Monk 42, was equipped with twin Cummins, but no thrusters. Maneuvering in small fairways and locks was always interesting, especially on windy days. Rather than bearing the expense of having a bow thruster installed (and because she was deficient in a few other features), I chose to buy another boat that was already equipped.


My Mainship 34T features both bow and stern thrusters with controls at both helm stations. And I had a wireless remote installed that I wear on a lanyard around my neck when docking or locking. Super convenient! I can walk my boat anywhere in almost any condition, including solo operation. And when I approach a tight spot on a wall, I simply draw parallel to the wall, and slip sideways into the spot between the adjacent vessels.


When solo, I bring the boat roughly into place, then leave the helm with wireless remote to handle the lines. If the bow or stern drifts off the dock or wall, even if I'm ashore, I can easily bring her back into place.


I'd not considered having a stern thruster. However, now that I have it, I'd prefer not to be without it.

 

[Ross Macdonald]

We have a 58 ft. pilothouse that weighs about 75,000 lbs. and has a draft of just under 5 ft. The boat is fully hydraulic with PTO's off of both engines. It came with a Keypower bow thruster. My dilemma was my prior boat (a Hatteras) had Hynautic controls and this boat has Kobelt electronic controls which had a steep learning curve for me. The torque of these big Cat engines caused the boat to jump pretty quickly tapping the levers in and out. So decided to install Keypower stern thruster to help me control the boat better. The stern thruster is a little more powerful than the bow. I feel like I can control the boat better in tight quarters. I have actually moved the boat side ways off of a side tie near the boat yard to get out in the fairway far enough to move forward. I would be interested to hear from members who have big heavy single displacement boats like a Nordhavn and how they use their thrusters. I would guess with those boats the thrusters on both ends are invaluable.

 

[Laurie]

You should look at the Dockstar Thrusters. We have a 34' CHB and they work great. The motors, batteries, radio, control electronics, and mounting rail are all in one compact unit. It is mounted using a T-track on a stainless tube. They are remote controlled so you can walk around the boat, even down onto the dock while docking. They are a fraction of the cost of the regular thrusters. You can also install them yourself. No need to be in dry dock.

 

[sahockey]

I designed a removable bow and stern thruster. They work great and only require about one to two minutes to attach or remove. So if I’m going into a crowded marina or other very challenging situation I quickly attach both thrusters to assist me.

The rear thruster is a very simple design that most anyone could reproduce easily and doesn’t require any underwater holes in the hull. Furthermore since it’s out of the water going under the hull it has almost no impact on speed or fuel usage even when it’s in position to be used. It is under water but higher than the hull depth immediately after the transom.

The bow thruster is more difficult to design and must be custom designed for every boat as it’s an external thruster. The most noticeable impact of the external bow thruster is its major impact on fuel economy and speed. This is due to adding an object underwater which produces a large drag. Although this thruster is also designed with no underwater holes in the hull.

So anyone consider an external bow thruster should be aware of its impact on your speed and fuel economy

 

[Baker]

I added a Yachtmaster stern thruster a few years ago on my 37 Nordic Tug and have been exceptionally please with its performance. A very easy install with one large hole and two small holes - less than 8 hours including three hours installing two batteries in series for 24v and 12v to 24v charger. Since it is hull mounted it sits about 18”” below surface and thrust is exceptionally good with little surface turbulence unlike a transom mounted thruster only inches below surface. With the motor surrounded by water the thruster can be run for long periods with no overheating. They claim you can run until the batteries are flat ... 20 minutes!

The batteries will likely melt before they “go flat”...ask me how I know...

 

[richardschmidt2759]

thruster

I put a stern thruster on my old 1981 mainship , it was a BIG help, but I think a bow thruster would have been better, I used a lewmar 185 mm ,could be used bow or stern. with different hardware, but since I did it my self it was much easier to mount on stern. but that said I know it would have been better in the bow $$$ but much harder to install.If you plan on keeping the boat for a while go bow, it will help re-sale value

 

[TemptUs]

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.

 

[TemptUs]

What district & when Dave? Comobill 8WR ‘97

 

[caltexflanc]

since her massive rudder and single 27" screw were practically useless at slow speed,

One thing people don't learn, or put themselves into a position of not being taught, is the proper use of thrust (quick bursts of throttle) in slow speed maneuvering. It's one of the guiding elements of "back and fill" sometimes mentioned here on TF, and often mentioned on sailing forums and classes. Add one more...

 

[Laurie]

Bow and Stern Thruster

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/