Externally Mounted Bow Thruster vs. Traditional Tunnel Type

[CampbellsSloop]

I have a 44 foot trawler (Gulfstar) and am looking to add a bow thruster. A company by the name of Yacht Thruster (a sister company to Side Power) has both a traditional tunnel type of thruster plus a new (3 years now) bow externally mounted model (e Thrust). I am at the Ft. Lauderdale boat show and at the Yacht Thruster booth, they strongly recommend the bow externally mounted model. Advantages (according to company personnel) for externally mounted bow thruster - water cooled so can run much longer, takes less amperage and because mounted further forward on hull, much more effective thrust.
Does anyone have any experience with both internal and external bow thrusters? Which one do you recommend. Other than perhaps an "add on" visually distracting appearance when the boat is up and running, I am tending to favor the externally mounted model. Any help or guidance would be appreciated. This is my first post as a new member to the Cruiser's Forum and I am anxious to learn the results of my post. Thanks from CampbellsSloop.

[captain465]

You might want to look at DIXON hydraulic stern thrusters. I ran a SEA//TOW boat with a single screw and the stern thruster for 16 years.....amazing what you can do with that setup. It is externally mounted on the transom and does not detract from looks at all.

[CampbellsSloop]

Thanks Captain - I have twin engines (inboards) so aft movement starboard or port is not a problem. I am concerned only with adding a bow thruster.

[delmarrey]

As long as one doesn't mind having an appendage hanging off the front of the boat it would be fine, and if you don't hit anything with it.

It would work great on my vessel due to the depth of the hull. Below the waterline up forward isn't enough for a tunnel. But I'm afraid it would affect the sailing dynamics of the hull.

http://www.yachtthruster.com/home-external

[CampbellsSloop]

Delmarrey - Thanks for the reply. I am currently at the Ft. Lauderdale boat show and the folks at Yacht Thruster here at the show tell me there is less drag than a folding propeller (whatever the proper name for that appendage is) and certainly less drag than a tunnel type bow thruster. They have a chart showing the numbers at the show.
I am not a salesman for any bow thruster company, I am just interested in real world opinions before I select an external or internal bow thruster.
I am surprised that there are not more Forum comments since bow thrusters have become so popular in boats 40 feet and up.

[capngeo]

Originally Posted by CampbellsSloop

Thanks Captain - I have twin engines (inboards) so aft movement starboard or port is not a problem. I am concerned only with adding a bow thruster.

Twin screw and you need a thruster?

[a64pilot]

Originally Posted by capngeo

Twin screw and you need a thruster?

Being a newbie here I wasn't going to be the first to question that. I think maybe he's thinking it would be a cool new toy to have. Nothing wrong with that, I believe a lot of electronics fall into that category for example.

[bizzy]

Twin screw and why would you need a thruster? maybe a day or two coming along side instead of running for your cheque book !!

[SailFastTri]

That external model would be a major vulnerability when (if?) you strike flotsam or if you snag a lobster line. Looking at the installation video, that sealant will eventually allow some water ingress, leading to corrosion and electrolysis. It would also be a worry for travellift strap placement.

If you had a single engine OK, but IMHO you'd be better off working on your technique with using your twin screws.

[Group9]

Originally Posted by capngeo

Twin screw and you need a thruster?

I used to run a 43 foot Wellcraft Portofina with twin IBs for my agency sometimes several years ago.

I was taking it off a commercial dock (with all kinds of jagged bolts and debris sticking off of it) one night with the wind blowing about 25 knots directly on the beam and pinning me to it. I would given a lot for a bow thruster that night.

(And, no, I didn't put it in that position, it was handed off to me like that).

[delmarrey]

There are a lot of twin screw boats out there with bow thrusters. Just go by any boat yard, you'll see. The longer the boat the less twin screws are effective, unless the beam were to be kept at the ratio to that of a 35/45'r.

There was a 70'+ that came into a our tight narrow marina and all the way in you could hear that thruster working away. W/o it, he would have been blown into other boats on the way in. It was amazing to see this monster docked next to a bunch of 30's.


.

[a64pilot]

OK, ships need tugs, I'll admit that, and if you have a 70 ft boat and I guess just can't wait on the wind, then OK. I'm new here and had the pre-conceived notion that mostly what was discussed was more in the line of "normal" boats, which I think of as up to maybe 50', now if we are talking above that, then that is outside of my range of experience as the biggest I have regularly docked was a 45' Sport Fisherman.
A bow thruster on almost any boat could be useful, maybe even open up opportunities that wouldn't be considered without one, but needed? Then as others have pointed out, does the positive aspects of this external bow thruster out weigh it's disadvantages? I think that is the real 'meat that should be considered, it appears that the person looking to buy can obviously afford one, but after the newness wears off, will they still be pleaded at having it?

[fjwiley1]

CampbellSloop...with your home port on Lake Erie/Sandusky, I'd suspect that you have encountered various types of floating debris that would cause concern for unforeseen strikes. I live on the St. Johns River here in Jacksonville and encounter the same types of debris as well as crab traps. We experience strong Nor'easter winds this time of year and I just removed 2 sections of some ones wooden dock that drifted under my dock next to my boat. Very fortunate that no one hit it during the night.
For these reasons, just my personal opinion, go for the internal thruster. You have enough horse power to not even notice any drag. You'll truly enjoy the bow thruster....Just my personal opinion.>>>>

[minaret]

Do a little searching here on the forum, and I think you'll find most people would think their predicted 10% loss of efficiency for a tunnel thruster is way too high. That said, I wouldn't put either on a sail boat. A proper installation does make all the difference, though.

[Cotemar]

What I would have given to have one of these Yacht Thrusters on my Catalina 380.
I was quoted $10,000 usd for a tunnel thruster installed.

This Yacht Thruster looks like a DIY, so that would have worked for me.
What does one of these coast for a 38 foot boat?