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Old 11-08-2012, 07:10   #16
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Re: hmmmm bowthrusters??

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Originally Posted by carstenb View Post
I've never had a bow thruster until this summer in my new boat. Generally, those who have boats without them say "If you can sail you don't need one." Those that have them say "It's a god send"
+1

Very well said.

Docking and close quarters maneuvering of a sailboat is a very complicated skill. You really wouldn't want to learn it with a thruster, because there are a lot of things you need to be able to do without it, which the thruster will allow you to avoid. You can do quite remarkable things without a thruster, with practice and skill. You can spin your boat around in place, you can do all sorts of other things. Proper use of spring lines adds a lot too.

HOWEVER, at the very same time I would say that I would never again want to handle a boat of more than say 45 feet without one. There are a number of things you can do with a thruster which you can't do any other way. Some of these things become crucially important when the boat is too big for crew to manhandle around.

The two most important things are these:

1. Creating sideways motion using thruster and counter-steer from the rudder;

2. Steering the boat when reversing (using the thruster like a rudder).

My boat is 54 feet on deck, about 60 feet LOA, the beam is 16 feet. She weighs about 25 tons loaded. I don't think I could handle her in close quarters without the thruster. And don't forget that the bigger the boat, the closer the quarters become.

There are also functions the thruster performs which may not be crucial, but are tremendously convenient and add a lot of safety to boot. One of them is getting off docks without scraping along. I always use the thruster to get off any dock -- I steer into the dock, give a burst of ahead, activate the thruster, and the boat moves sideways off the dock without moving forward. This allows me to motor away in whatever direction without scraping along the dock, and with much less risk of tangling with boats moored ahead or behind. Tremendously useful. The same thing could be done with spring lines, but very laboriously and you need enough skilled hands to do it, and besides that, springing off entails lots of risks (lines in the water and on the prop, a line gets stuck on something, etc., etc.). I never use the thruster to get onto a dock unless I need a small correction of the bow position at the last minute, but I always use it coming off.

The comment about sizing the thruster right is right on. A thruster is nearly useless if it is not powerful enough. Mine is 12 horsepower and properly sized. It won't hold the bow into a strong wind (but no thruster will; in fact many smaller boats with a lot of freeboard can't be held into a strong wind with their main engines), but it will hold the bow against a moderate wind trying to blow me off a dock while coming in. If 12 horsepower is not enough, then you need someone pushing in the dinghy with 25 horsepower -- a maneuver we have used on a few occasions (I remember particularly once getting onto a pile mooring in Yarmouth (when Yarmouth still had them) in a full gale).

Coming out of St. Malo a couple of weeks ago, I was rafted up to an Amel 54 on the quay, ahead and behind were rafts of two and three boats-- in a dead-end aisle of the port. I could not go forward for more than two or three meters, and behind I had to get through a spot hardy wider than my boat. Without a thruster, I would have needed to find five or six guys and walk the boat out -- a nightmare with 25 tons of boat and impossible in any kind of wind. With the thruster, we were able to get out under our own power -- I was able to reverse out and precisely -- to a few inches -- place the boat laterally by steering with rudder and with tiny bursts of thruster - like a car with four-wheel steering. A crowd had gathered to watch the inevitable crash as we got underway -- and kindly applauded when we threaded the last needle, and neatly spun around on our boat's axis to get under way towards the lock and out to sea.

So is a bow thruster a "decadent, unnecessary, luxury, not needed by real he-men sailors with salt in their veins"? Imagine yourself in that situation before you answer.
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Old 11-08-2012, 07:27   #17
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Re: hmmmm bowthrusters??

We have just moored on the canal du Midi in the south of France near to a hire boat base. The hirers are given very brief tuition and sent off on their way, most of them try and use the bow thrusters to steer the boat while doing 6 knots ! Thank god the engineers built strong bridges as we've seen 2 hire boats smack them on the way through when they screwed up. They are handy if used correctly. I have a friend on a 39 ft cabin cruiser driven 5 cylinder Nanni engine coupled to a well engineered hydraulic system, he has both bow and stern thrusters and being hydraulic are virtually silent, he also has a 7.5 kv genny driven by the same system.
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Old 11-08-2012, 07:49   #18
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Re: hmmmm bowthrusters??

For those of you advocting that having a thruster either forces you to rely on it or not learn how to drive you boat... I disagree, in fact, you could use that arguement on any piece of modern equipment, like chartplotters, sail handling systems or even GRIB Weather files.

I have owned three sailboats and done lots of comercial work in the San Francisco Bay on both power and sail. I have driven sail boats up to 80 feet and power boats up to 165 feet. In my opnion, a bow thruster makes life easier in some situations and I would never own a boat over 40 feet without one (Power or Sail) for the reasons given by DOCKHEAD.

I also disagree with the hydrodynamic arguement. I have a 47 sloop and have raced against sister ships and saw no appreciable difference in speed. I am sure there is some loss due to hydrodynamics, but it is not enough to worry about it, unless you are racing high end one design sailboats. If you disagree with me, ask a marine architect who should be able to provide you with the reasons they are designing boats with them...

Yes, retractble thrusters on recrational boats are a great idea, but they come with to many working parts and on a sailboat would be disaster if it failed and didn't retract.

The bottom line is bow thrusters make life easier, like roller furling jib or a chartplotter....

The real question comes down to money and if you believe that it is worth it to make your life a little easier on you boat.
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Old 11-08-2012, 09:04   #19
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Re: hmmmm bowthrusters??

Thrusters are used on ships and large workboats. The people who operate those vessels are not exactly amateurs. Be careful to not let a thruster become an excuse for not developing good boat handling skills.
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Old 11-08-2012, 09:20   #20
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Re: hmmmm bowthrusters??

Agree with the majority on this one. My boat came with the BT. In about 95% of dockings I can manage without it, but like others have said, in tight spaces it is invaluable. Single handing most of the time, I cannot run about fending off etc. Taking things slowly, thinking ahead, and having the comfort of a BT to hand has so far resulted in no dings (touch wood)
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Old 11-08-2012, 09:25   #21
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Re: hmmmm bowthrusters??

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Originally Posted by captainKJ View Post
If getting a bow thruster you might want to consider a stern thruster also. they come in handy on 35 foot boats. There is also another system called DP. it keeps you in one position for as long as you want. this way you don't have to anchor, just keep the engine running all night to power the DP and all the other electronics along with the AC units.

real sailors don't need thrusters
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Old 11-08-2012, 10:41   #22
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My experience is using prop, rudder wash and throttle. once I understand these tools it's amazing how I can spin a boat. Not against bow thruster for many boats. Think often once you get the hang of the tools you have you won't need the bow thruster.
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Old 11-08-2012, 11:47   #23
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Re: hmmmm bowthrusters??

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Originally Posted by jeremiason View Post
I also disagree with the hydrodynamic arguement. I have a 47 sloop and have raced against sister ships and saw no appreciable difference in speed. I am sure there is some loss due to hydrodynamics, but it is not enough to worry about it, unless you are racing high end one design sailboats. If you disagree with me, ask a marine architect who should be able to provide you with the reasons they are designing boats with them...
Well I am one. *grin* BS Naval Architecture and Marine Engineering, Webb Institute 1982. There is a good reason commercial and military shipping have doors over the thruster tunnels.

My colleagues design boats with thrusters because customers want them and will pay for them. That doesn't mean they are a fundamentally good idea.
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Old 11-08-2012, 13:51   #24
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Re: hmmmm bowthrusters??

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Well I am one. *grin* BS Naval Architecture and Marine Engineering, Webb Institute 1982. There is a good reason commercial and military shipping have doors over the thruster tunnels.

My colleagues design boats with thrusters because customers want them and will pay for them. That doesn't mean they are a fundamentally good idea.


Exactly. Also, I am sure you could race against a sister ship and see no difference. There are so many variables to consider. Perhaps you're tanks we're full and theirs were close to empty, or their boat just has more gear, poorly tuned rigging, bad sails, a poor helmsman, etc. etc. and I am also sure that at least in some cases there would be no difference under certain conditions, ie lots of wind. The only way to really tell is to sail a boat with no thruster, then install one and take it out again and record the difference. I have done this, and in light airs it was about half a knot and an extra few degrees of rudder angle, not a big deal to some, a huge deal for others.
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Old 11-08-2012, 15:19   #25
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Re: hmmmm bowthrusters??

In my opnion, a bow thruster makes life easier in some situations and I would never own a boat over 40 feet without one (Power or Sail) for the reasons given by DOCKHEAD.

while BT can make life easier people rely on them to much and lose the art of boat and ship handling. I worked with a captain of a private yacht, 98 feet, he was 77 years old, the boat did not have a bow thruster. He could put that boat anywhere, wind current did not matter. he knew how to drive and what the boat would do before it did it. that is seamanship. I also worked on a 150 foot private yacht that did not have one. The captain knew how to drive.

Worked with a mate who wanted to put a BT on a 35 foot Intrepid that had twin 300 engines. Captain told him if he could not drive a 35 foot twin engine without a BT to go home. Mate quit.

a 40 foot boat with a BT. thats ridicules IMHO. spend the time learning how to maneuver your boat and you wont need it.
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Old 11-08-2012, 18:28   #26
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Re: hmmmm bowthrusters??

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In my opnion, a bow thruster makes life easier in some situations and I would never own a boat over 40 feet without one (Power or Sail) for the reasons given by DOCKHEAD.

while BT can make life easier people rely on them to much and lose the art of boat and ship handling. I worked with a captain of a private yacht, 98 feet, he was 77 years old, the boat did not have a bow thruster. He could put that boat anywhere, wind current did not matter. he knew how to drive and what the boat would do before it did it. that is seamanship. I also worked on a 150 foot private yacht that did not have one. The captain knew how to drive.

Worked with a mate who wanted to put a BT on a 35 foot Intrepid that had twin 300 engines. Captain told him if he could not drive a 35 foot twin engine without a BT to go home. Mate quit.

a 40 foot boat with a BT. thats ridicules IMHO. spend the time learning how to maneuver your boat and you wont need it.
I agree. My boat is 60' loa and 65,000 lbs, no thrusters, no problem. Our crew is me and my diminutive wife, plus our five year old twins. We are currently tied up inside busy tight for space Friday Harbor.
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Old 11-08-2012, 18:44   #27
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Re: hmmmm bowthrusters??

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I agree. My boat is 60' loa and 65,000 lbs, no thrusters, no problem. Our crew is me and my diminutive wife, plus our five year old twins. We are currently tied up inside busy tight for space Friday Harbor.

well, no disrespect meant,,,, BUT,,,,,,,, maybe you are doing it all wrong and should put in a BT instead of learning how to handle a boat,,,,,do astern thruster while you are at it
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Old 11-08-2012, 19:15   #28
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Re: hmmmm bowthrusters??

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I agree. My boat is 60' loa and 65,000 lbs, no thrusters, no problem. Our crew is me and my diminutive wife, plus our five year old twins. We are currently tied up inside busy tight for space Friday Harbor.
Must be the twins...one off the bow, one off the stern; possibly a bridle setup between the hulls. Lucky you didn't have quads, you'd have been able to get a trimaran and really show off. Cheat.
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Old 11-08-2012, 19:26   #29
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Re: hmmmm bowthrusters??

I like them in bigger boats and when the marina is tight. The drop type seems to give me more headaches than the permanent models but sure this is dictated by bow shape.

What do you guys think of stern-thrusters?

b.
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Old 11-08-2012, 19:31   #30
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Re: hmmmm bowthrusters??

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I like them in bigger boats and when the marina is tight. The drop type seems to give me more headaches than the permanent models but sure this is dictated by bow shape.

What do you guys think of stern-thrusters?

b.

A must have for every boat. just think of it,,,an inflatable 12 foot dingy with bow and stern thrusters,,,, you would be the envy of every sailor.

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