Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-28-2022, 05:20 PM   #1
Member
 
City: Salt Spring Island
Vessel Name: Cathryn Grace
Vessel Model: Pacific Trawler
Join Date: Jun 2020
Posts: 21
Pacific Trawler, 37' Bow Thruster

Hello Mariners,


Our Bow thruster will not engage.
We can hear the Motor try to engage BUT it will not turn.


During the Winter months I start the engine once /Month and turn the thruster on to keep the passage clear.


I dove in the drink to clean any debris/mussel/growth.


Thoughts on popping the motor off and doing a dry test?
Any issues with taking motor off while boat is the the water?
IE is this a "on the dry" issue?
Is there a spot from inside the hold where one can spin the drive with a wrench?


Thank you in advance, from Salt Spring,

Mark
Rollysflyinghigh is offline   Reply With Quote
Old 06-28-2022, 06:15 PM   #2
TF Site Team
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Black Dog
Vessel Model: Formula 41PC
Join Date: Jul 2015
Posts: 16,387
It would probably help if you include make and model of thruster.
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you aren’t one, there is no explanation possible.
Comodave is offline   Reply With Quote
Old 06-28-2022, 08:05 PM   #3
Member
 
Vessel Model: Sunnfjord 42
Join Date: Jan 2013
Posts: 11
Thursters typically have a shear pin (cheap) that breaks if the load exerted by the motor on the gearbox (expensive) becomes excessive. Replacing the pin is probably easy but the question would remain as to why it broke in the first place. Excessive fouling of the props might be the issue or I've even heard of it happening if you go from one direction to the other too rapidly. It needs some investigation.
heysteve is offline   Reply With Quote
Old 06-29-2022, 06:00 AM   #4
Arc
Guru
 
City: Long island
Vessel Model: Eastern
Join Date: Aug 2018
Posts: 506
If you take the motor off to test it be very careful. The motor without any load can explode from centripetal force. Only tap the switch to test. We build motors and have seen this with high power dc motors.
Arc is offline   Reply With Quote
Old 06-29-2022, 12:05 PM   #5
Senior Member
 
jungpeter's Avatar
 
City: Everett
Vessel Name: LIBERTY
Vessel Model: TOLLY 48
Join Date: Mar 2013
Posts: 425
Quote:
Originally Posted by Rollysflyinghigh View Post
Hello Mariners,


Our Bow thruster will not engage.
We can hear the Motor try to engage BUT it will not turn.
If the motor does not turn, does your thruster circuit breaker open? Or does the motor spin freely, but the propellor provide no thrust?


During the Winter months I start the engine once /Month and turn the thruster on to keep the passage clear.


I dove in the drink to clean any debris/mussel/growth.
And presumably, you've tested the thruster immediately AFTER verifying the tunnel is clear?


Thoughts on popping the motor off and doing a dry test?
Yeah, lots. This is a VERY bad idea.

Any issues with taking motor off while boat is the the water?
No. Removing the motor is difficult but not impossible, due to clearance issues. However, the gearcase provides a watertight boundary with the interior of the boat. You can remove the motor while the boat's afloat.
IE is this a "on the dry" issue?
Not necessary, but can be if the gearcase has failed.
Is there a spot from inside the hold where one can spin the drive with a wrench?
No. You can attempt to rotate the driveshaft on the gearcase with the motor removed, but a free-spinning drive shaft does not necessarily indicate the gearcase has not failed. Only observation of the propellor while manually rotating the propellor can verify the gearcase integrity.


Thank you in advance, from Salt Spring,

Mark
Hi Mark. I believe your thruster is likely a SidePower 4hp single-propellor unit. If so, there is a shear pin on the motor shaft that provides torque to the gearcase and propellor. If your motor spins freely when you engage your thruster, but you observe no thrust, then this pin has likely failed, or (much less likely), your gearcase has failed. SidePower provides instructions, and appropriate part numbers, on how to replace this pin. Yes, it can be done in the water, as the gearcase provides the watertight seal to the interior of the boat with the motor removed.

Don't be fooled into thinking this is a "simple" fix, or any old steel pin will work to replace the OEM shear pin. Access to enable replacement of this pin is difficult, as the thruster motor must be removed, and the space is tight on the Pacific Trawler 37. This pin is manufactured from properly-tempered steel, and has a subtle taper to enable it's proper installation. I suggest you use an OEM shear pin for this replacement operation, seat it properly, and use Locktite to ensure it stays in place.

However, if you motor fails to spin when you engage your thruster, AND you're positive the thruster tunnel is clear, you either have a failed motor, or possibly a poor electrical connection to the motor. The obvious first thing to check is your 12vdc battery cable connections to the thruster motor, to ensure they are clean and tight, and you actually have ~13.2VDC at the motor input. Next, verify your control electronics are also clean and tight. If all appears good to go, but the motor will not spin when mounted onto the gear case AND the thruster circuit breaker has not opened, then it's likely your motor itself is faulty.

It is a REAL BAD idea to remove the motor, and attempt a "spin test" by engaging the thruster control. All DC motors produce essentially infinite torque at zero rpm, and it's a very bad idea to hand-hold a 4HP DC motor while attempting to restrain the inertia of the case at startup. The motor will likely jump out of your hands and make a giant mess, or possibly injure you. MUCH better idea to remove the motor from the boat and take it to a local electrical motor shop for testing.

Ditto on general R&R of this bow thruster assembly. Far better to get a trained mechanical technician from a local boatyard to check this thing out for you, particularly if this is your first time investigating this problem. In my opinion, bow thrusters are not particularly DIY-friendly, as troubleshooting is not trivial. And trust me here-a 4HP DC electric motor is WAY more powerful than you might suspect. Personally, I treat them with great respect.

Regards,

Pete
jungpeter is offline   Reply With Quote
Old 06-29-2022, 01:25 PM   #6
Member
 
City: Salt Spring Island
Vessel Name: Cathryn Grace
Vessel Model: Pacific Trawler
Join Date: Jun 2020
Posts: 21
Jungpeters, response

Wow,



TY TY TY


Excellent advice.


Oddly enough the CB does NOT pop when I use the thruster (Kept toggle open longer then 3secs), while the solenoid(?) appears to engage.


While I was in the water cleaning the passage and BT prop, (Ready for the cringe moment?), I called up to my partner to try and run the unit. (I utilized CRM and SOP's to insure we didn't have an accident.) We ran thru this procedure multiple times, BUT no joy.


I have a young fella coming down to finish off my hull cleaning and replacing Zincs, So we will do some trouble shooting.


I will confirm the motor and model of this BT.


I suspect the heavy 12v cables are energized and that the solenoid only needs to engage for the line to activate the motor.


Thank you again JUNGPETER, for your detailed thoughtful analysis .


Mark
Rollysflyinghigh is offline   Reply With Quote
Reply

Tags
bow thruster, pacific trawler 37

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 02:39 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012