What are the drawbacks of bow thrusters?

[Jammer]

Well, aside from cost, maintenance, and the loss of potential bragging rights from being able to dock without one.

Meaningful loss of performance under sail due to added drag from the tunnel?

Risk of significant leakage at the joint between the tunnel and the hull? Greater potential for collision damage?

Anything else?

[a64pilot]

Maybe entanglement of prop with a line, weight, increased battery capacity and or electrical system to support one. On my boat, I’d lose some storage capacity in the bilge.
Are retractable ones like on an Amel very common? I wouldn’t think so, but it does seem to solve some issues, but is more complicated of course.
I used to want one, now have decided to do without, but I’m only about 45’ total length too.
The increased drag with a hole in the hull can be lessened I believe by careful shaping of that hole, how much less, I don’t know.

[robert sailor]

Forget about additional drag, IF the hull has been properly shaped in front and behind the tunnel, certainly seen lots not done properly because of course it takes a bit of skill and time and time costs money. That aside as A64 mentioned your adding complexity, cost,weight and maintenance to your boat. Our boat came with one and the airline pilot that owned it previously had made sure it was done right. Our first 2 years in the Med really showed me the value because most marinas are Med moored and your backing up into some very tight spots, often with good cross winds and this is where you really appreciate a bow thruster. Never had one before so really didn't need one but I can see the attraction. If I was cruising the Caribbean or South Pacific I would never have one, don't need it.

[S/V Illusion]

The biggest drawback is dependence. Inevitably people who have them depend on them and while they usually work, inevitably they won't.

And when someone writes here that their thruster has always worked, consider adding to the end of their sentence " so far".

[puffcard]

Think the weight would be very hard to get on a 16ft canoe. lol. I was looking at your boat. I would like one over 50ft or cruising the med, or own a tight spot slip, like my last one.
All good points above, plus the added wiring and controls for the hog.

[chris07732]

None, if you frequently single handle dock a 40' full keel motorsailer. Typical installations are risk proof, IMHO. I self installed a Lewmar unit 3 yrs ago, its been a godsend to this 74 yr old sailor

[Eder]

Its like air conditioning...only those that have them can't live without (I have bow thruster & air conditioning lol)

[Jammer]

Originally Posted by S/V Illusion

The biggest drawback is dependence. Inevitably people who have them depend on them and while they usually work, inevitably they won't.

Hmm. I thought of mentioning dependence/addiction in my opening post. I would think a disciplined helmsman would use them judiciously, particularly since heavy use leads to earlier failure.

Originally Posted by puffcard

Think the weight would be very hard to get on a 16ft canoe. lol. I was looking at your boat.

I just use a 14 year old kid with a paddle. Works great but won't fit in the tunnel.

FWIW I just ordered one quart each of Interlux Perfection and Interlux Perfection Plus for the OTCA. It is going to be red on the outside and gloss varnish on the inside. Winter project.

There is a larger boat in my future.

[robert sailor]

I'm not so sure about dependence, maybe, maybe not. I don't bother with it in the Caribbean but it was nice to have in the Med but there is a difference between having to have it. Bit like diesels, nice to have but I've sailed for months when I couldn't get a part but I like having the engine makes life a bit easier. Each individual is different.

[svHyLyte]

Originally Posted by Jammer

Well, aside from cost, maintenance, and the loss of potential bragging rights from being able to dock without one....
Anything else?

There's nothing quite so sad as watching some poor fool desperately/hopelessly thumbing his/her "bow thruster" to no avail while he/she is being blown down on a row of pilings/yachts to leeward in a stiff cross wind (unless of course, yhou have the misfortune of being on one of the leeward yachts!). In 40_ years I have yet to see any of any use save those that are side mounted on Cruise Ships needing to do 180's in restricted harbors and even them, not when they're stuck in a good cross wind. If you can't figure out "Prop Walk", rudder angle; and, springing a yacht into/off a key, a thruster won't be of much value either.

FWIW...

[Jeanneau 45.2]

I don't agree that a bow thruster is never legitimately needed. I need mine when in marinas (much less frequent now that we are full time cruising, but still occasionally necessary) with very narrow fairways which invariably have power boat anchors protruding into the fairway (and since narrow fairways mean more slips in a given area, not that rare a layout). I can stop the boat with the slip abeam midship, pivot in place around my fin keel, and proceed straight into the slip. As they say in the army ... "if you got em, smoke em". The argument against having one based on over reliance / complexity / etc is like saying no power boat needs twin screws (which when used properly provide the benefits of a bow thruster) ... even though such setup is common. All IMHO. Alan

[billknny]

It depends on the boat...

I handled a 40 foot sailboat with skeg rudder without a thruster for many years, and never missed it. Kind of wondered why anybody wanted one. You learn. Installing a thruster on that boat would be a waste of money. Take a lesson and learn how to drive a boat.

My current boat has the prop well forward of the skeg hung rudder. Close quarters maneuvering without the bow thruster is truly, very, very difficult. There is almost no propwalk, and rudder response is low. The position of the prop mean you can't really kick the boat around with a short burst of power.

Fortunately, the boat builder installed a thruster that is totally up to the challenge. A 24 system runs a 10KW (13 Hp!) motor with retractable propeller (no tunnel!). It has more than enough power to push the bow against a strong cross wind. The prop is deep enough when down in the running position that it can get a great "bite" without sucking air.

I have seen a lot of thrusters that are underpowered, and so high in the hull and close to the waterline they cavitate when used. Worse than worthless. If you can not count on it, when conditions are bad, what use is it?

[Jammer]

Thanks for the replies.

I anticipate docking effectively singlehanded in most cases since my wife is physically unable to do much line handling and has little interest in learning the helm. As in all things done shorthanded, it is appropriate to configure the boat for the easiest docking possible. Perhaps a bow thruster would play a role, hence my questions.

I also have designs on some river cruising where there are tides, currents, bridges, and traffic. Again trying to stack the deck in my favor.

[NYSail]

My boat came with one and I love it. We try to seldom use it because I do believe in dependency leading to a lack of feel for the boat. However when wife is docking sometimes that little bump is a nice thing.

[ranger58sb]

Originally Posted by Jammer

Hmm. I thought of mentioning dependence/addiction in my opening post. I would think a disciplined helmsman would use them judiciously, particularly since heavy use leads to earlier failure.

Originally Posted by Jammer

I anticipate docking effectively singlehanded in most cases since my wife is physically unable to do much line handling and has little interest in learning the helm. As in all things done shorthanded, it is appropriate to configure the boat for the easiest docking possible. Perhaps a bow thruster would play a role, hence my questions.

I also have designs on some river cruising where there are tides, currents, bridges, and traffic. Again trying to stack the deck in my favor.

I have not heard/read the heavy use per se leads to earlier failure. What I have read is that lots o' sustained thruster time on an electric model can lead to overheating, low batteries, and time-outs.

Some of that can be controlled by the operator's technique; poor technique mentioned in other posts doesn't have to become your standard.

Some can be mitigated during the shopping (higher hp, 24V vs. 12V, etc.) and installation (more batteries closer, etc.) phases.

As with most other things on a boat, ya use what ya got... and it makes sense to me that you set up your boat to best deal with your particular circumstances.

-Chris