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Old 11-08-2012, 19:50   #31
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Re: hmmmm bowthrusters??

Well, an inflatable normally will have an outboard that pivots and so it does not really need a stern thruster ... ;-)

Will be interesting to see when yachts get those pivoting saildrives as we can see in some working boats.

The bad news is the more thrusters there the more I can watch owners having next to nil idea of how to maneuver their floating caravans ;-(.

b.
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Old 11-08-2012, 20:00   #32
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Re: hmmmm bowthrusters??

Fenders out; boathook and esky within reach of your hammock, and a camera for sharing the tastier moments on Youtube.

Me, I'll confine my harbour maneuvering to the twilight hośrs, just in case my refusal to get a BT or an engine backfires on me.....humble crow is a dish best eaten privately. Though at .25 of a knot my screwups shouldn't be too entertaining.....
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Old 11-08-2012, 20:52   #33
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Re: hmmmm bowthrusters??

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Originally Posted by sabray View Post
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, 21:35   #34
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Re: hmmmm bowthrusters??

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Originally Posted by micah719 View Post
Fenders out; boathook and esky within reach of your hammock, and a camera for sharing the tastier moments on Youtube.

Me, I'll confine my harbour maneuvering to the twilight hośrs, just in case my refusal to get a BT or an engine backfires on me.....humble crow is a dish best eaten privately. Though at .25 of a knot my screwups shouldn't be too entertaining.....

Quarter of a knot is rarely a good idea when docking. The more the wind, the more aggressively you need to manauever to counter it, or it will have its way with you. Learn to park your boat like Captain Ron, it's a valuable skill. This is even more true of big boats with lots of wind age. I usually enter a slip at 2-3 knots depending on conditions, and brake it down last second. Throwing the brakes on hard also causes the prop walk to act like a stern thruster, which will allow you to park the boat perfectly if you have planned for it.
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Old 12-08-2012, 01:01   #35
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Just to let everyone know, for a second time, I in no way want a bowthruster. I can handle my boat easily,alone. I only created this to get others opinions.
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Old 12-08-2012, 05:43   #36
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Re: hmmmm bowthrusters??

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Originally Posted by barnakiel View Post
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.

Got two bow thrusters and two stern thrusters on my work boat, but in the last 3 years I can count the times I used a stern thruster on one hand.
With twin screw boats, hardly needed unless for some specialist applications.
Maybe its the way I was brought up, move the stern of boat by splitting the sticks and using the rudders. Lots of new guys coming in to work boats will see stern thrusters and use them just because they are there, and less skill is needed.
All the mates on my workboat are discouraged from using the stern thrusters until they can properly drive without them.
On a yacht, I think they would be a waste of space, money, and time needed for the extra maintenance.

With bow thrusters, it means that the boat is expected to work in harsher conditions than would have been comfortable say 30 years ago.
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Old 12-08-2012, 13:12   #37
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Re: hmmmm bowthrusters??

And if your engine or morse control fails ? (I have seen this happen especially when you go astern quickly). Dont approach anything faster than you want to hit it.

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Quarter of a knot is rarely a good idea when docking. The more the wind, the more aggressively you need to manauever to counter it, or it will have its way with you. Learn to park your boat like Captain Ron, it's a valuable skill. This is even more true of big boats with lots of wind age. I usually enter a slip at 2-3 knots depending on conditions, and brake it down last second. Throwing the brakes on hard also causes the prop walk to act like a stern thruster, which will allow you to park the boat perfectly if you have planned for it.
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Old 12-08-2012, 14:34   #38
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Re: hmmmm bowthrusters??

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And if your engine or morse control fails ? (I have seen this happen especially when you go astern quickly). Dont approach anything faster than you want to hit it.

The faster you go into a dock,,,,the louder the noise is when you hit it......the more people who look over when they hear the loud noise,,,,,,,the more drinks you have to buy at the yacht club tell bullsh-- stories of how the engine quit on you when you needed it most

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Old 12-08-2012, 15:10   #39
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Re: Hmmmm - Bowthrusters ??

Fair point...depends on conditions. I was planning on avoiding docks whenever possible anyway. Expense and annoyance mitigation strategy. I'd prefer to invest in bombproof anchoring gear and become maestro of the dinghy. Dock Queen? Never....

The plan features one lousy subsurface throughhull for seawater intake. I'm shying away from even having an electromotor, as appealing as it is.

In my wanderings on the sailing web perusing the old salty ways of doing things, I notice that in the days of harbours crowdeed with workboats the boats were sturdier, less obsessed with a grandpiano-finish on the topsides, had fenders and used them, and made up for lack of technology by learning and applying skills. The danger is that gadgets will overcome lack of skill and sometimes prudence as well...


I wonder what Fstbottoms has to say about fouling and bow thrusters?
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Old 12-08-2012, 17:58   #40
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Re: Hmmmm - Bowthrusters ??

Didn't even spill the Champers....

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Old 13-08-2012, 03:40   #41
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Re: Hmmmm - Bowthrusters ??

Nice vid....nice boat, lovely day, all gadgets in working order. The tight space in the marina gives me the willies, though....
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Old 13-08-2012, 05:39   #42
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Re: Hmmmm - Bowthrusters ??

Well, it's day she there is no wind or waves.

I will say that the larger your boat , the more a bow thruster is useful. ON big boats, say 50 feet, you end up having to back them, simply because you can't see what is happening 50 feet away. How close are you to the dock etc. So you back in. A bow thruster is pretty nifty to have here. And yes, I can dock a 50 footer without one, but I don't mind if my life is made a little easier.

As I said at the start - if you are just starting out or have a small boat you are better off without one. You will then develop the skill sets necessary to dock a boat well. Once you have those you will be able to use a BW if you deem it necessary or not as the situation requires.

We have all sat in harbors and heard the BW on a boat growling along indefinitely. This is the mark of a skipper who can't sail his boat
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Old 13-08-2012, 12:56   #43
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Re: Hmmmm - Bowthrusters ??

Quote:
Originally Posted by barnakiel View Post
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.
Can you elaborate? I've only had one delivery with a drop-down thruster and the thruster was stuck up. Is that the problem you have had? I like the concept but the execution of good ideas in the recreational market is often lacking. I'm always open to real data.

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Quote:
Originally Posted by Auspicious
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.
Good an expert!

In my compassion between my sister ships, there was no noticable speed difference between to boat side by side, one with thruster and one without while sailing.

I know that the hydrodynamics change, but how much on a recreational boat?
An expert is a drip under pressure right? *grin*

I haven't look at the data for a long time so I'm working from slightly dusty memory. What I recall is that the drag increase is several percent. That's enough to be significant on commercial ships (fuel cost) and military vessels (maximum speed). Scaled to recreational boats I would expect the drag to be up a good bit (figuring tunnel diameter as a percent of waterline length to be 1% or more vice 0.25% (ish) on a ship).

What's the impact? On a long range, offshore cruiser passages will be discernibly longer and fuel costs higher.

Side-by-side tests are misleading as marginal differences are overwhelmed by crew skills and actions. Just because something is small doesn't mean it won't add up to big numbers over time.

If that were the only impact you could probably talk me into a thruster as a good deal, particularly for day-sailing on bigger boats and even coastal cruising. Both spend a higher percentage of time in docking evolutions than a passage-maker. Add the impact on storage, the dirt from wearing motor brushes, the maintenance issues (the above poke at growth plus zincs), and the reality that in extremis they are almost universally not powerful enough and I don't think they make sense on recreational boats.

We haven't even talked about how close they are to the waterline and the resulting cavitation and aeration.
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Old 13-08-2012, 13:24   #44
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Re: Hmmmm - Bowthrusters ??

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Can you elaborate? I've only had one delivery with a drop-down thruster and the thruster was stuck up. Is that the problem you have had? (...)
Well, ours was stuck ... out. This was the most recent case.

Another day, another boat: leaving the dock we drop the bow mooring line and sure thing it catches on the extended thruster. It takes a diver to clean the mess.

When I refer to the bow shape I mean on some boats the bow is flat and so the drop-out system may be the only one that can be retro-fit.

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Old 13-08-2012, 13:42   #45
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Re: Hmmmm - Bowthrusters ??

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Well, ours was stuck ... out. This was the most recent case.
Interesting. As I said I really like the concept but I keep thinking about growth. The trunk would have to be watertight when closed; some kind of flushing would help.
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