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CARL · 19-06-2006, 08:38

Can any one inform me if there is enougth bow in the water on a Luders offshore 47 built by cheoy lee for a bow thruster to be effective. I really am not keen to fit one, unfortunately my berth in our locall marina is so tight and risky to get to in anything but the slightest breeze that i am seriously thinking of fitting one any imput would be appreciated regards Carl.

markpj23 · 19-06-2006, 12:23

I have a possible alternative - but rather than hijack your thread I'll post it under Seamanship & Boat Handling.. see "Poor Man's Tug"

New England Bow Thruster · 15-05-2007, 06:02

You boat would need an 8" thuster providing about 225 to 260 lbs of thruster to be a worth while proposition. The location would be ideally an equal diameter length below the water line or at least 6" and at least 4" from the bottom of the boat and as far forward as possible. Some simple measurements and inspection of the forward area for the hull for other obstructions will tell you the story. There are very few boats out there that cannot accept a thruster. Some installs get more creative than others.

CARL · 15-05-2007, 10:52

Thanks for info, will start looking at cost ,probably in Cherbourg France, one other question roughly how much speed will be lost. Regards Carl.

**Alan Wheeler** · 15-05-2007, 12:39

Carl it depends. Firstly on the type. The most common is the tunnel thruster. The turbulence created is a factor of your boat speed, planning or displacment (planing the bow maybe free of the water) and the size diameter of the tunnel. 8" will produce more turbulance than 6" for instance. Then dependign on hull shape and boat size, there are alternatives to tunnel types. There are systems that retract as well. Some have covers that follow the contour of the hull and simply pull shut to allow the hull to look and act normaly. So really, you need to look at what is available from the manufacturers and the costs of the unit and most importantly, the cost once the thing is installed. Some maybe cheaper as a unit to purchase, but more expensive to install. Then of course, you have electric power and hydraulic powered. But once again, it depends on the size of the vessel.
Maxpower
Sidepower
Lewmar
Westma
Vetus
are all the ones I know of.

New England Bow Thruster · 15-05-2007, 15:07

Carl

A good install will have a negligable impact on speed, especially in a heavy cruiser. I doubt you will notice the difference. Light cruiser racers are a little different and are the ones that gain the most benefit from a retractable unit. A spoiler should be made as part of a good install in a tunnel thruster to deflect the laminar water over the hole rather letting it rush in and swirl in the tunnel. Thats where the theoretical drag is created. Your choice will come down to how deep your pockets are. A retracting system will 3-4 times more expensive than comparable tunnel thruster and will more than likely need to be hydraulic. Again you will need in the neighborhood of 250 lbs of thrust and that is still dependent on how far forward you can push the tunnel installation. Considering that a Lewmar TT 8" 24 V thruster system (our most popular model for boats in your clas)with a single station control and dedicated battery and charging system would run about 10,000.00 USD installed you can see the financial commitment a retracting would be.

Sonny · 30-07-2007, 14:55

I saw somewhere a bow thruster that attaches to the bow of the boat (sail or power). You can install it yourself and you don't have to put this huge hole in the hull below water. I can't find the article right now but will look for it. It costs thousands less than having one installed through the hull.

**knottybuoyz** · 30-07-2007, 15:08

Quote:

Originally Posted by Sonny

I saw somewhere a bow thruster that attaches to the bow of the boat (sail or power). You can install it yourself and you don't have to put this huge hole in the hull below water. I can't find the article right now but will look for it. It costs thousands less than having one installed through the hull.

Bow Thrusters, Stern Thrusters, Boat Docking, Boating, Yachting Equipment, Side Shift

My buddy put the stern thruster version on the back of his Bayliner 3888 and had to upgrade to 24 volt to get enough thrust to make it work properly.

New England Bow Thruster · 30-07-2007, 16:14

The Side Shift is considered a light duty thruster and is a good alternative for a lot of smaller boats under 30' realistically. More than that and they really have a tough time performing well and a traditional thruster system makes more sense and is certainly more robust. Stern thrusters usually need to be a bit bigger than the bow thrusters as they will need to overcome more drag and leverage effect of wider beam, shafts, struts, lower units what have you. Many installs in larger vessel will use two stern thrusters. A 24 volt system will not bog down like a 12 volt system so it was probably his only alternative in a less than ideal set up. I am sure the price was right though.

waterworldly · 23-10-2007, 03:37

I have seriously considered one boat that the thruster comes standard, but have also considered others where it would have to be added. The question is: is it worth it? In my less than experienced mind, "an ounce of prevention . .. ". I am leaning towards it due to the fact that I will be in many strange anchorages/mooring fields/marinas as the years progress, and it would be a comfort to know I have direction control without forward momentum, especially in the more tight areas in strange crowded ports. Am I off the mark on this thought?

New England Bow Thruster · 23-10-2007, 06:02

Waterworldly

You are right on the mark in fact. Yours are just some of the reasons cruisers are wanting to have thrusters installed. You will get all those benefits and usually increase the value of the boat you install the unit in. You will also have complete sideways movement possible with a thruster and a twin screw vessel with very little effort once you learn the technique. Parallel parking is actually possible with a little practice. Single screw vessels are not nearly as daunting to dock especially when docking stern to. With the advent of wireless controls, mooring and med-mooring become much easier to do. Captain and crew can be much more effective as a team. we have had older customers want them just so they can bring the boat close to the dock in order to board in a heavy cross wind. They don't have to yank on dock lines any more. There are a whole host of reasons to do it. Each one particular to the customer.

Lancerbye · 23-10-2007, 06:05

I presently have a bow thruster which makes docking very easy however if I was thinking of putting a new system in I would be looking at getting the system that uses a water jet pump off the main engine and four 1.5 to 2in. jets around the boat. Two in the bow and two in the stern under water. The installation cost would be less and the holes are smaller. A joy stick then controls the valves to give you thrust where you want. I think this would be a sweet system.
http://willdo.nl/images/WillDo%20Jet...lDo3luikEN.pdf

Jack Flanagan · 10-07-2008, 09:21

Hello Carl,I just stumbled upon your message concerning bow thrusters by surfing on that topic on Google. Your message is two years old but it is topical enough for me to make it worthwhile to join this network. This may be too late to be of any help to you but perhaps can be of help to me. I too own a Cheoy Lee Offshore 47 designed by Bill Luders. I am right now in the same boat you were (no pun intended) in that my boat is difficult to maneuver in tight quarters. Besides responding to the wind, she backs to starboard regardless of speed and rudder position. I am considering putting in a thruster. I am told by a trusted professional source in Port Townsend, Washington, that it can be installed easily in the place of the forward water tank. Cost for me should be a little under $9,000. Did you have one put into your boat? If so what kind? Are you happy with it? My concerns, beside its impact upon speed, is weight in the bow, as I had a bowsprit made for the boat that makes her a bit bow down if I am not careful with balance. My boat is yawl rigged. I have rebuilt a great deal of her in the last 15 years, including the hull and deck. Plans for the bowsprit came from Bill Luders some years a ago by the way. I would be happy to exchange information on our boats. Jack

Jolly Roger · 10-07-2008, 11:18

A bow thruster is one of the first things I will fit when I get my 50' ketch, simply on the grounds I may be short handed many times. I've looked at the main manufacturers, but does anyone actually have one of the water jet type thrusters, running of the engine? I can't find anything on these on the web.