Thruster mania

[duncan99210]

I can understand the need to use a thruster in manoeuvring a boat in a marina or on to a mooring. Makes sense, especially in a tight situation. However, I cannot understand why you would need to use a thruster when anchoring...... All too often round here (Greece) boats will enter an anchorage and then use their thrusters whilst dropping astern to anchor. Why? Just doesn’t make any sense. Once the hook is down and dug in, the bow will point upwind to the anchor and no amount of thruster power will change that for more than an instant. Grrr. Rant over.

 

[JumbleDuck]

but it can only be tested practically in a boat fitted with one. As already said doubt if many, or indeed any sailing school boats are so equipped

Of course, but sailing schools have to move with the times too. Maybe it's time their boats were equipped like most modern cruising yachts of the same size.

As others have suggested inappropriate use is probably an indicator of lack of skills in the basics..

Absolutely - that's what almost cost me a wind vane yesterday ...

 

[johnalison]

Most people motor too fast approaching a berth, needing reverse to stop the forward motion and prop walk can screw your course (but can be used if you know how it affects you own boat). The bigger the boat, the more it takes to stop it, so think you are berthing a supertanker.

I think that this is often the problem with the inexperienced. They lack the confidence to go slowly. When going slowly, this increases the effect that the wind has, which may be either helpful or unhelpful, but which in any case needs to be taken into account. I often se people struggling to get into a berth because they have approached too fast. Yesterday was a prime example. Coming into my alley I only had to bring the boat to a near stop and the wind of only about 10 kn brought my bows round to line up with my berth, whereas a visitor in a similar-sized boat needed three attempts to do the same thing nearby. As I often say, there are few situations that can't be made more expensive by using more throttle.

 

[JumbleDuck]

I think that this is often the problem with the inexperienced. They lack the confidence to go slowly. When going slowly, this increases the effect that the wind has, which may be either helpful or unhelpful, but which in any case needs to be taken into account. I often se people struggling to get into a berth because they have approached too fast. Yesterday was a prime example. Coming into my alley I only had to bring the boat to a near stop and the wind of only about 10 kn brought my bows round to line up with my berth, whereas a visitor in a similar-sized boat needed three attempts to do the same thing nearby.

It amazes me how many people (again including chummy yesterday) rely on people ashore with ropes to stop the boat. I know there are some situations where you have to keep way on till the last moment to maintain control, but even my long-keeler responds well to a short burst of throttle with the helm over. I aim to stop the boat dead alongside the pontoon so that my small crew can step ashore with a line.

As I often say, there are few situations that can't be made more expensive by using more throttle.

I like it!

 

[Sybarite]

on a purely aesthetically base, the noise of the bow thruster is to me the worst possible sound one can hear in a marina, mooring, port, whatever.. Not to speak of bow thrusters used ad libitum in totally windless/tideless early mornings by the boat next of you.

Which was my case a few days ago. On a perfectly windless day a 23' speedboat next to me used his bow thruster to straighten up to leave the marina.

 

[Robin]

60 years of multiple boats without a thruster, including a twin engine 47 foot trawler motor yacht, no probs just pre planning and forethought. Now have a twin engine semi displacement mobo with both bow and stern thrusters, very handy indeed on the occasions needed. Our home berth is in sight of the marina lock entry and like others when we hear thrusters going constantly we get out on deck ready to fend off. There seems to be so many that forget they even have a rudder(s). after a lifetime in saily boats saying how easy it is with twin engines on mobos, we had to relearn and pre-program prejudices. Twin engines can change direction of alignment very easily, just not necessarily direction of movement overall where momentum plays a big part. Moving the bow one way with a thruster moves the stern the opposite way and some it seems never look behind them. I miss the big rudder and fin keel combo on a single engine sailboat, and whilst our current mobo does respond to it's small rudders it still needs to be moving through the water to do so, luckily not especially fast in our case as it responds at even tickover speeds. Some mobos we see and even some yachts are using thrusters whilst doing maybe over 5 knots -WHY?

BTW windage on a mobo is much more of a problem than on most rag and stickys and notably so at slow speeds in tight spots.

All too easy to critique from afar.

 

[prv]

On a perfectly windless day a 23' speedboat next to me used his bow thruster to straighten up to leave the marina.

A 23' speedboat is unlikely to have a rudder. He'll have either an outboard or an outdrive, both of which steer with directed thrust so can only turn the boat when in gear. The amount of thrust generated at tickover in gear is likely to be higher than is really suitable for slow-speed manoeuvering, and he has no keel to pivot around.

Of course it could be managed without a thruster, but since it's there, using it may not be as daft as it seems to someone used to how easily sailing boats manoeuvre.

Pete

 

[tudorsailor]

Maybe sailing schools should have boats with bow thrusters so that they can teach how to use them! On my 49 footer I have a skeg mounted rudder. Went I first acquired the yacht (10 years ago) and having never sailed anything so big, I employed an instructor to teach me how to handle the boat. His instruction was to reverse with the wheel locked in the mid-position and steer only using the bow thruster to protect the rudder. When maneuvering away from a side-to berth I was shown how to ferry glide away by turning the wheel towards the berth to move the stern out and then use the stern thruster to move the bow out.

Having said all this, these things can only be achieved if the thruster is powerful enough. A couple of years ago, I ended up skippering a chartered Bavaria in the Ionian. I was embarrassed to be one of those "typical charterers who do not know how to handle a boat". The thruster was underpowered and reversing turned out to be "difficult" in the afternoon crosswind. In full view of the spectators I ended up side-to instead of stern-to. I have never criticized charterers who make a hash of maneuvering since.

TudorSailor

 

[capnsensible]

The only way a school boat will ever have a bow thruster is if they have a yacht under management and the owner had it fitted.

Otherwise it will never happen. Not unless someone is giving them away free.

 

[pagoda]

Our "new to us" boat is 42' and has a factory fitted bow thruster. Never had one previously. Prop walk on this boat is a fraction of previous boat.
The single bow thruster only pivots you around your keel- it is no use whatsoever for pushing the entire boat sideways- as some imagine. It gets occasional use to tighten up turning circles, or nudge the bow to a finger until a line is secured. I could not imagine any function when working a mooring or anchoring. We usually try for either a midships bridle or a quick aft spring when coming in. With almost no way on, or none at all. With those in place it's easy to creep ahead and secure the rest. I do find myself wincing when I hear thrusters being used for more then 4 or 5 seconds. People do it. Going slower is the least expensive option. If you think you are going to be blown off, then add more fenders on that side? Parking yourself briefly alongside another boat - with plenty of fenders is not a hanging offence. Everybody makes mistakes at times. We came unstuck almost in Portaferry (Strangford narrows) with about 5 Kts through the fingers from astern, with almost 20Kts wind as well. Undignified but no harm done. For short handed sailing it is handy!

 

[johnalison]

A 23' speedboat is unlikely to have a rudder. He'll have either an outboard or an outdrive, both of which steer with directed thrust so can only turn the boat when in gear. The amount of thrust generated at tickover in gear is likely to be higher than is really suitable for slow-speed manoeuvering, and he has no keel to pivot around.

Of course it could be managed without a thruster, but since it's there, using it may not be as daft as it seems to someone used to how easily sailing boats manoeuvre.

Pete

On several occaions I have spent a happy hour or so watching people receiving instruction on the use of motorboats. In each case, from Salcombe to Wolgast, the tuition took place in a small RIB and the learner was made to manoeuvre at a dead slow speed onto buoys, pontoons and such like, often for an hour or two. If only more owners chose to subject themselves to this kind of discipline life could be a lot more pleasant for them and the rest of us, and I mean sailing as well as motorboats.

 

[tudorsailor]

Our "new to us" boat is 42' and has a factory fitted bow thruster. Never had one previously. Prop walk on this boat is a fraction of previous boat.
The single bow thruster only pivots you around your keel- it is no use whatsoever for pushing the entire boat sideways- as some imagine. It gets occasional use to tighten up turning circles, or nudge the bow to a finger until a line is secured. I could not imagine any function when working a mooring or anchoring. We usually try for either a midships bridle or a quick aft spring when coming in. With almost no way on, or none at all. With those in place it's easy to creep ahead and secure the rest. I do find myself wincing when I hear thrusters being used for more then 4 or 5 seconds. People do it. Going slower is the least expensive option. If you think you are going to be blown off, then add more fenders on that side? Parking yourself briefly alongside another boat - with plenty of fenders is not a hanging offence. Everybody makes mistakes at times. We came unstuck almost in Portaferry (Strangford narrows) with about 5 Kts through the fingers from astern, with almost 20Kts wind as well. Undignified but no harm done. For short handed sailing it is handy!

Come to the Med! Moving big yachts in marinas designed for small yachts is a challenge. Reversing onto the quay to go stern-to is altogether a different skill to going alongside. On the rare occasions that I can go alongside, I regard this as a much easier option when short handed.
You can move the boat sideways as I said, but only when going forward. Not only is this useful when leaving a alongside berth but also when leaving a stern-to mooring when the cross wind wants to pin you to your neighbor.
TS

 

[Resolution]

I can understand the need to use a thruster in manoeuvring a boat in a marina or on to a mooring. Makes sense, especially in a tight situation. However, I cannot understand why you would need to use a thruster when anchoring...... All too often round here (Greece) boats will enter an anchorage and then use their thrusters whilst dropping astern to anchor. Why? Just doesn’t make any sense. Once the hook is down and dug in, the bow will point upwind to the anchor and no amount of thruster power will change that for more than an instant. Grrr. Rant over.

Well I often use my bow thruster to keep the bows from being blown off immediately after the hook has gone down, and while we are waiting for the boat to drift back and take up the slack / dig in. It means we drift back in a straight line from where the anchor went in. No massive advantage, just a bit neater, and quicker if I use a touch of reverse to speed up the process. As we have the thruster, why NOT use it? Just another tool to help move the boat.

Is there an element of reverse snobbery here from sailors whose boats do not come equipped with thrusters??

 

[Robin]

Well I often use my bow thruster to keep the bows from being blown off immediately after the hook has gone down, and while we are waiting for the boat to drift back and take up the slack / dig in. It means we drift back in a straight line from where the anchor went in. No massive advantage, just a bit neater, and quicker if I use a touch of reverse to speed up the process. As we have the thruster, why NOT use it? Just another tool to help move the boat.

Is there an element of reverse snobbery here from sailors whose boats do not come equipped with thrusters??

Tempting, granted, but unnecessary. A drifting boat will drift side on until pulled straight as the anchor bites, then it can be dug in under engine or reversed mainsail etc if required but the initial snub that turned it straight will hopefully have started the set process.

Still it does no harm, other than get the armchair 'spurts' off

 

[prv]

A drifting boat will drift side on until pulled straight as the anchor bites

That's often how I detect that it has bitten

Pete

 

[stevebrassett]

Only time I have used a bow thruster was on a Norfolk Broads cruiser. Not essential , but it didn't half make manoeuvring a 42 foot flat bottomed boat easier!

 

[dslittle]

Oh dear. Today I might have worried some people unnecessarily. As I was going alongside into a space about a metre longer than my boat on a calm windless day with no tide I gave a spurt of bow thruster to check that it was working. I didn’t actually use it to moor up but I do apologise to anyone who came out with fenders to fend me off their boats!!!

 

[Robin]

That's often how I detect that it has bitten

Pete

Me too:encouragement:

 

[jimi]

My bow blows off very quickly and there's been a few times I wished I'd had a bow thruster. Going into a lock recently with the only free space on the port side with wind on the port and prop walk to starboard was one of those times!!!

 

[Tranona]

The only way a school boat will ever have a bow thruster is if they have a yacht under management and the owner had it fitted.

Otherwise it will never happen. Not unless someone is giving them away free.

Or its use becomes an examinable part of the syllabus!

However, if you know how your boat behaves without it you will need to learn how to modify that behaviour to make it easier for you. I spent an hour during the commissioning of my boat learning about this aspect with an instructor. Enough to get a grasp of the basics.

Still learning though as new situations arise.