Stern thruster mainship 390

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MSOUZA2

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Jul 17, 2009
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DOES ANYONE OUT THERE HAVE A STERN THRUSTER ON THEIR 390. iS IT EXTERNALLY MOUNTED, IF SO HOW DO YOU*ACCESS THE MOTOR AS THE SWIM PLATFORM IS SEALED FROM THE REST OF THE HULL. AM I WASTING MY TIME TO EVEN CONSIDER THIS UPGRADE
 
In my mind, a sternthruster is a waste of time and money. The stern can be moved sideways simply by turning the helm all the way over and giving a short shot of forward thrust. The bow however is not so easily moved, so a bowthruster can be somewhat justified. A little instruction from a good boathandler will give you the skills you need to avoid the expense and maintenance of the sternthruster.
 
MSOUZA2, From experience, I can tell you that a stern thruster is a nice thing to have when you are moving a large, single screw, heavy displacement boat into crowded spaces. It makes it possible for me to single hand Delfin without worry.* On one of my prior vessels - a Cape George 36' full keel cutter with a tiller - I learned how to navigate the boat just with rudder and prop, so I understand what can be done without either bow or stern thruster.* The same techniques that worked for my sailboat worked for a 200 ton barge I piloted on the Moselle River in Germany.* However, in my dotage and now piloting a mere 65 tons of steel, I must say I find the stern thruster rather nice to have.* Whether it is worth it for a 39' vessel is harder to judge.* I suppose it depends on how you want to use the boat.* By yourself?* Lots of new marina visits?* If so, it may be worthwhile, and other than the cost, you won't regret having it.
 
I'm with Carey on this one. Unless you already have a bow thruster, I think installing a stern thruster with no bow thruster is the least useful combination there is unless you have a very specific docking situation that absolutely requires you to move the stern dead sideways with no forward thrust at all.

If your boat has no thruster at all and you only want to spend the money to install one, then I believe the bow thruster is the smart answer. As Carey says, you can move the stern sideways with what you already have, the rudder(s) and prop thrust.

But the ony way to move the bow straight sideways while leaving the stern where it is is with a bow thruster.

If you can afford both, or already have a bow thruster, then there will be times when a stern thruster might make life easier. Particularly if you are not comfortable with the method and control coordination required to move a boat around precisely with rudder, forward and reverse thrust, and inertia alone.

There is a company that makes bolt-on stern thrusters for boats like the typical trawler that have very little draft across the stern.* It's called the Cap Sante stern thruster.* You can find it under "Thruster" at http://www.capsante.com/main/.* Don't know if they're good, bad, or indifferent but I've seen them on several boats in our area.


-- Edited by Marin on Wednesday 10th of February 2010 10:33:10 PM
 
You certainly don't need a stern thruster on a 390. Listen to Carey & Marin....Hard over, (either direction) back & fill and that bow is going to swing to your satisfaction. (A bow thruster, however, covers up a multitude of helmsman's mistakes.) I have one and I use it! There's a great DVD from Bennett Marine, that is dedicated to "Handling the Single Engine Boat" and it covers all the various maneuvers.
 
Our little 32 footer came with a Sidepower stern thruster (as well as a bow thruster). Would never have put one on myself. For some reason, whether its the fact that the tube is too close to the surface or that there is too much resistance in the electrical cables, the darn thing is quite anemic and draws a heck of a lot of juice compared to the bow one. If its calm, yes, it will move the stern but I rarely use it. Must admit I rarely use the bow one as well.
 
We have a hydraulic bow thruster and get home that can run for hours.* I have looked at stern thrusters that can be turned and also become a get home.* Our single prop walks to port so moving the stern to port is not difficult. Just thrust to port with the rudder/prop and put in reserve to continue the prop walk to port. Can turn the Eagle 360 just putting in forward and reverse. *However, to get the stern to Starboard and turning to port is a lot harder, which is where the bow thrust comes in handy.* **I would not have a Single without a bow thruster.*
 
Thanks for the advise, I think I will do some more practicing before I make any decisions. I have had sailboats for the past 25 years, this is my first power boat. Never had any trouble with the sail boats knowing what to expect in handling. Being so high up with almost no stern visibility was my main concern. We are in a very tight slip and ther is little room for error. Again thanks.
 
I don't have any thrusters. With twins, wouldn't ever use one. My last boat, however, was a Cooper, Seabird 37, sail, with a long shallow keel, single screw behind a barn door rudder.
Now that is a combination that is doomed to back as accurately as a game of chance. If I had a stern thruster I would have used it. Had I done so, I never would have been as frustrated, and I never would have learned how to manage any boat, without a thruster, in tight situations, where I needed it to go where I wanted. I recall having to leave a crowded dock in a strong cross wind, where I had to get from a side tie at the dock, out past boats rafted onto the ones in front and behind me, into the channel, then back all the way down the finger before being able to turn around, all in a strong cross wind. No opportunity to practice, but getting aggressive on the boat speed in reverse was just the ticket, and after I learned that little trick, using the rudder to actively steer in reverse, I never looked back (pun intended).
Since then I have taken the challenge with several power boats, in tight manouvering, and once you think about the physics of it, there is absolutely no need for a thruster.
Practice.
Better if you can practice where there are no $M bits of plastic where you might stray.
The first trip when my present boat was new to me, coming dockside where the current from a nearby river mouth affects the docking, I came alongside but told the willing hands on the dock to go back to their boats, as I was practicing. Just a couple of tries and I became proficient enough to do it in front of a crowd without flinching, no matter what the wind or current conditions. You just need to pay attention and try to understand how wind and current are affecting your boat. The satisfaction you will get from mastering the peculiarities of your boat is worth more than the little extra control a thruster might give you.
 
Skinny Dippin' has ONLY a hydraulic stern thruster on a single-screw and I can get into any spot a bow-thrusty can get into in the same conditions. I highly recommend one. I look at it like this: You already steer the boat from the stern. This allows you to just enhance that ability. It makes it far simpler to deal with and understand when adjustments are needed. At the end of the day, if you should lose thrust, you still have the ability to maneuver from practice. You aren't "propped up" by a crutch you've gotten used to. Stern thrusters are externally mounted and don't require a ton of expensive glass work to install. It's not tucked into a little hole and that makes it easy to clean and keep barnacle-free.

TBH, I try not to use it too often. Being new to boating, I want to be sure I can do without because the day that it lets me down is still ahead. I feel good that I am gaining the ability to get around with a single-screw WITHOUT relying on "The Toe Chopper".
 

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