Bow thruster

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Jeff F said:
There was only one time I really missed the stern thruster. I was on the Illinois River approaching a lock from the bottom with a strong tailwind. 30 knots plus. The lock master insisted that I secure starboard side to the chamber.

I could have done it with a helper, but without the thruster I couldn't stop the boat without the stern swinging out and catching the wind. After a couple of aborted attempts they closed the gates and allowed me to free float during the lift. Problem solved. If they'd offered the port side tie up it would have been easy.
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Stories like that are why I'm no fan of underpowered thrusters. Once you know the boat well, you can do a whole lot without the thruster. But every once in a while you get to a situation where the thruster is pretty much the only way it's possible to do something. And it's almost always due to high winds, etc. where an underpowered thruster won't be enough to help the situation.
 
rslifkin said:
Stories like that are why I'm no fan of underpowered thrusters. Once you know the boat well, you can do a whole lot without the thruster. But every once in a while you get to a situation where the thruster is pretty much the only way it's possible to do something. And it's almost always due to high winds, etc. where an underpowered thruster won't be enough to help the situation.
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My case was no thruster. Even a weak one probably would have made it possible.

And I'm doing lots of things that most people wouldn't attempt. So I'd argue against upgrading the bow thruster in the OP's case.
 
backinblue said:
Does the tank run the full width of the stern? Doesn't really matter if the thruster is centered. I don't see why you would need 2 unless they were 2 small ones to equal 1 of adequate size. Also don't know why they would need to raise and lower unless they are below the hull bottom when lowered.
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The tank runs most of the stern. There is about 12 to 14" storage compartments on ether side of the tank.
 
There are external mount thrusters, eg. Exturn. Probably less of a risk on the stern than the bow.
 
Jeff F said:
The lock master insisted that I secure starboard side to the chamber.

I could have done it with a helper, but without the thruster I couldn't stop the boat without the stern swinging out and catching the wind.

If they'd offered the port side tie up it would have been easy.
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Good story Jeff, but a lesson learned here is not to listen to someone if it puts your boat in jeopardy. The people (on the dock / over the radio / in the lock masters office) don't know exactly what is happening on your vessel.

If it's going to result in damage or injury, ignore the hell out of everybody. Captain is in charge of his ship. Deal with the consequences later.
 
Mako said:
Good story Jeff, but a lesson learned here is not to listen to someone if it puts your boat in jeopardy. The people (on the dock / over the radio / in the lock masters office) don't know exactly what is happening on your vessel.



If it's going to result in damage or injury, ignore the hell out of everybody. Captain is in charge of his ship. Deal with the consequences later.
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Oh I was never in any danger. I'm always happy to try something if I have a solid escape plan. I've got so much prop torque I can *always* abort a starboard-to landing. I got on the wall a couple of times, but couldn't get outside fast enough to get the midship line on the bollard. That's maybe six ft aft of the PH door. The wind was getting funneled into the lock chamber somehow.

There were no floating bollards on the other side. It was windy enough that floating was a bit of a chore with no stern thruster, so I made my way over to the other side and maintained position with the occasional bump in reverse as the lock filled.

Edit to add: I'm reluctant to insist on special treatment, or even draw attention to myself as a solo traveller. These are commercial locks, and it is assumed by all that the captain has the last say WRT vessel safety. If I'd had someone with me it would have been doable.

I'd hate to have them implement a policy like some other commercial locks that prohibits solo passage.
 
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Jeff F said:
A little personal anecdote: my previous boat was a Mainship 34 MY. No thrusters.

I kind of enjoyed driving the Mainship the way it was. It forced me to think about springs, and to use them on occasion.
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Ditto our first "big" boat. Wifey for crew, springs often.

-Chris
 
When we bought our Mainship 34 we had a bow thruster intalled as one of the first upgrades. We used Florida Bow Thrusters and they had it completed in 2.5 days and did a fantastic job!
I can back into our slip without it but it may take 5-10 Fwd/Rev shifts as our slip is tight. Now with the thruster it is incredibly easy to get into our slip with only 1-3 Fwd/Rev shifts and can be done with no crew. Single screw, back to port, light boat, high windage, Best upgrade and well worth it!
 
backinblue said:
Wouldn't something like this fit on 1 side of the stern?

https://www.sleipnergroup.com/thrus...sx50-external-stern-thruster-12v-w-controller
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I applaud the effort! But no, the fuel tank is there. No way to bolt it on. Like I said, New England Bow Thruster looked at it and the wanted to put in two thrusters that lower them self's into the water ahead of the fuel tank. Now that's what they come up with.

The only way I came up with is using a water type thruster though the storage compartments. But I was told there made for small boats.
 
Iggy said:
I applaud the effort! But no, the fuel tank is there. No way to bolt it on. Like I said, New England Bow Thruster looked at it and the wanted to put in two thrusters that lower them self's into the water ahead of the fuel tank. Now that's what they come up with.

The only way I came up with is using a water type thruster though the storage compartments. But I was told there made for small boats.
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That's what I meant. Mount this in one of the storage compartments at the far port or starboard side of the stern.
 
Jeff F said:
Maybe mount this on the underside of the swim platform?

https://shop.sideshift.com/collections/houseboat-thruster-products/products/hb340-houseboat-thruster
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There is no swimming platform. But a deck that extends out with the 2nd fuel tank in it.

I found a boat that is 95% like mine. https://sailnorthwest.com/boat/pacific-trawler/

If you look at the pics of the stern. Just as you pass the door you see a hatch. There is storage from port to starboard but it end about 10" toward the transom. From that point back is the 2nd fuel tank. You can even see the two storage compartments on ether side. So N.E. Bow thruster wanted to use the space on ether side of the hatch.
 
Jeff F said:
Maybe mount this on the underside of the swim platform?

https://shop.sideshift.com/collections/houseboat-thruster-products/products/hb340-houseboat-thruster
Click to expand...

There is no swimming platform. But a deck that extends out with the 2nd fuel tank in it.

I found a boat that is 95% like mine. https://sailnorthwest.com/boat/pacific-trawler/

If you look at the pics of the stern. Just as you pass the the door you see a hatch. There is storage from port to starboard but it end about 10" toward the transom. From that point back is the 2nd fuel tank. You can even see the two storage compartments on ether side. So N.E. Bow thruster wanted to use the space on ether side of the hatch.
 
We had what I considered to be a vastly underpowered Vetus bowthruster on Sanderling when we bought her. I spent the bucks and added the largest unit the current tunnel could support (almost doubled the rating). Had to do it out of the water as the entire unit, including the in-tunnel tail was replaced. Worth it, IMHO.

The only thruster I've experienced on a "normal" trawler was on a friends DF40 who had a 24 volt system with a corresponding thruster. Had to hold onto a grab rail when the thruster was operating (almost).

One suggestion: don't bother running a separate thruster bank; run it off a LARGE house bank. We had a 1200 amp house bank that did everything (engine start, genset start, inverter, etc). Never had a problem.

Iggy said:
Wonder if this is worth doing? I have a 40' trawler with the 21 year old thruster that produces, as the spec's say 147lbs. of thrust. Now the next model up does 161 or 14lbs more. Cost $1,100 just change the motor out. Bolts right in!

The next model does 212lbs of thrust, but everything needs to be replace but the tunnel. Cost around $3500 if I do it myself. But I will need to add one more battery due to the increased amperage. More$$

This being my first boat with a bow thruster I don't have any experience with one. So my questions, is 14lbs more worth the it?? The spinoff to this, the new motor uses 25A less. From 355 down to 325, a very small plus.

Another way to put it! How many lbs to HP with thrusters?
Click to expand...
 
BobMc said:
We had what I considered to be a vastly underpowered Vetus bowthruster on Sanderling when we bought her. I spent the bucks and added the largest unit the current tunnel could support (almost doubled the rating). Had to do it out of the water as the entire unit, including the in-tunnel tail was replaced. Worth it, IMHO.

The only thruster I've experienced on a "normal" trawler was on a friends DF40 who had a 24 volt system with a corresponding thruster. Had to hold onto a grab rail when the thruster was operating (almost).

One suggestion: don't bother running a separate thruster bank; run it off a LARGE house bank. We had a 1200 amp house bank that did everything (engine start, genset start, inverter, etc). Never had a problem.
Click to expand...

Yes, my house does power the thruster. I can see the advantages.
 
Iggy said:
Yes, my house does power the thruster. I can see the advantages.
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Big advantages. See my earlier comment on pack amperage.

Edit to add: if you lower house max current expectations cabling and such get easier and failure cases go down. I've got a couple of start batteries on my thruster. They love that stuff.
 
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Our thruster is 12v. When they were doing the installation it was pointed out that the house bank was close to a 18' run. Decided to have them install new battery and charger within 2' of the thruster. They did give a good deal on the "new requirements" and I am very happy
 
Iggy said:
Wonder if this is worth doing? I have a 40' trawler with the 21 year old thruster that produces, as the spec's say 147lbs. of thrust. Now the next model up does 161 or 14lbs more. Cost $1,100 just change the motor out. Bolts right in!

The next model does 212lbs of thrust, but everything needs to be replace but the tunnel. Cost around $3500 if I do it myself. But I will need to add one more battery due to the increased amperage. More$$

This being my first boat with a bow thruster I don't have any experience with one. So my questions, is 14lbs more worth the it?? The spinoff to this, the new motor uses 25A less. From 355 down to 325, a very small plus.

Another way to put it! How many lbs to HP with thrusters?
Click to expand...

Depending on the age of the thruster, I would pull the electric motor and take it to a starter/alternator shop and have them rebuild it. I recently did that to my bow and stern thruster motors and the improvement in thrust was very noticeable. The cost was around $300 for my stern thruster motor rebuild and $500 for the bow thruster.
 
Forgive me if I repeat a comment above -- I haven't read them all.


Wind force varies with the square of the wind speed. If your thruster works OK in a 15 knot crosswind, a ten percent increase in thrust will make it work OK in a 15.7 knot wind. A 44% increase -- the $3500 option -- will get you up to 18 knots of cross wind.


To my way of thinking, 10% is nowhere near worth it and even the 40% increase is marginal.



If you have the slightest doubt about your cable size, you'll get much better results per dollar by doubling whatever cabling you have.


Jim
 
Circumnavigator said:
Forgive me if I repeat a comment above -- I haven't read them all.


Wind force varies with the square of the wind speed. If your thruster works OK in a 15 knot crosswind, a ten percent increase in thrust will make it work OK in a 15.7 knot wind. A 44% increase -- the $3500 option -- will get you up to 18 knots of cross wind.


To my way of thinking, 10% is nowhere near worth it and even the 40% increase is marginal.



If you have the slightest doubt about your cable size, you'll get much better results per dollar by doubling whatever cabling you have.


Jim
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The wiring as far as I can tell is good
 
Circumnavigator said:
What size wire and what's the one way distance battery to thruster? From the amperage quoted above, I assume it's 12VDC.


Jim
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Not sure on the exact wiring size. I had to replace an 4/0 cable just the other day. I would say the next size bigger. But on the next warm day I will check it out. MAYBE the thing to do is replace the wiring. The boat is 20 years old.
 
What kind of boat are we talking about here? We have a 39ft Mainship 350. Thruster is under powered for very strong winds for sure. With this model having lots of windage, small rudder placed too far forward, the thruster is pretty much mandatory to dock. You can't even turn into a slip down a small channel without using the thruster, turn radius is horrible. Trying to come along side any dock with just the slightest of breeses and using rudder alone will have you swinging the wheel enuff to measure it in rpm LOL! Requiring the use of thruster in the Mainship 350/390 and leaving the rudder amidship is the only way to dock these suckas. The point is, depending on the boat, years of skill do not determine your use of the thruster. Take a 30 or 36 Willard with big rudder, sailboat keel, and double ender and no thruster at all, you can put that baby in any slip or pull alongside any dock with ease.
 
Iggy said:
The tank runs most of the stern. There is about 12 to 14" storage compartments on ether side of the tank.
Click to expand...

Check out SideShift thrusters. They mount above the waterline and the mount could be extended to mount above the fuel tank. It takes 4 bolt holes and 2 cable holes. Pretty simple DIY installation.
 
Comodave said:
Check out SideShift thrusters. They mount above the waterline and the mount could be extended to mount above the fuel tank. It takes 4 bolt holes and 2 cable holes. Pretty simple DIY installation.
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We went though this in earlier post. It can not be done.

Yes, of course check the connections:facepalm:.

But how do you tell if the cable is good though and though. I had a boat with twin engines and one would not start. I combined them and it started. That told me that I had a bad connection or cable. Connections looked good, but I sliced the cable open and the inside was burned.
 
Measure voltage at and across each connection and see if there is a voltage drop. If there is a drop then the connection is suspect.
 
For a once yearly event, I’d hire someone in a dinghy / pusher boat to help you make the spin. chances are the yard has someone skilled at that.
 
Go out on a calm day and practice maneuvering backwards. It's a fun and rewarding challenge.
 
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