Bow Thruster Manufacturer opinions

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bucketlist1

Veteran Member
Joined
Aug 31, 2020
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85
Location
Canada
Vessel Name
Lemon-Aid
Vessel Make
Ranger Tug R-27
Some of the boats i am looking at ( Downeast and Trawler , single engine ) don't have a bow thruster . Any recommendations on the different brands ? would be for 30- 40 ft range .
 
We had Sidepower in our last boat and had good support from them. I am putting Sideshift on our new boat, time will tell.
 
I have sidepower bow and Vetus stern. they both are fine. the difference is the Vetus prop is held on by a very small 6mm bolt. the sidepower is on a robust shaft with a 19mm bolt.
 
As I said above we had a traditional Sidepower thruster in our last boat. We sent with Sideshift on our current boat due to internal constraints. If I were to go with a traditional thruster it would be Sidepower again.
 
Bow Thruster

NOTE: RULE: when it comes to thrusters, REMEMBER, there is NEVER to much power. Biggest mistake is getting one that is to small !

Nothing under 10-HP is where I draw the line for that size boat.

don't spend the money for the variable speed type, not worth the extra complications & electronics.

The base one works with relays, and is very reliable & can be bypassed easily of need be in an emergency & is easy to diagnosis if ever an issue.

You can't fix electronics at sea unless you have expensive spares.:banghead:

you normally operate it with a few short 5 to 10 second bursts of full power for the needed number of seconds. I have run mine for couple minutes & it did not over heat & turn it self off.

For your 30 to 40 foot boat, I would recommend 10-HP to 13-HP range.

stay away from plastic propellers as they break if debris get in them, when they are running with that kind of HP twisting them.

For that HP, you need 24-volt electric DC power source from 2 - 12-V AGM - Starting batteries in series & it is the easiest to install ! Do not get deep cycle batteries for this thruster !

I use a "WESMAR" brand & they are in Seattle area & it is very HD commercial grade unit & it has been excellent for me for well over a decade of heavy usage.

Probably a 8 inch tunnel would be right size, I recommend a Dual counter rotating 8 inch props style & size. Get Tunnel as low under the water line to reduce cavitation & effectiveness.

Get a Battery to battery 12-24 charger to keep the two (or four) 24-volt thruster battery recharged. I use only group 31 sized starter - AGM batteries & do a Series / Parallel wiring set up to get the 24 -volts with 4 group 31 AGM starting batteries to give me the power for what I needed.
NOTE? 2 can work as well as the 4 , just a little shorter running time endurance.

Plus, with the B to B charger, it tops them off after the house batteries reach full charge when under way or when recharging at dock or with gen-set. So, Keep it simple.

Good Luck.

Alfa Mike
 
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NOTE: RULE: when it comes to thrusters, REMEMBER, there is NEVER to much power. Biggest mistake is getting one that is to small !

Nothing under 10-HP is where I draw the line for that size boat.

don't spend the money for the variable speed type, not worth the extra complications & electronics.

The base one works with relays, and is very reliable & can be bypassed easily of need be in an emergency & is easy to diagnosis if ever an issue.

You can't fix electronics at sea unless you have expensive spares.:banghead:

you normally operate it with a few short 5 to 10 second bursts of full power for the needed number of seconds. I have run mine for couple minutes & it did not over heat & turn it self off.

For your 30 to 40 foot boat, I would recommend 10-HP to 13-HP range.

stay away from plastic propellers as they break if debris get in them, when they are running with that kind of HP twisting them.

For that HP, you need 24-volt electric DC power source from 2 - 12-V AGM - Starting batteries in series & it is the easiest to install ! Do not get deep cycle batteries for this thruster !

I use a "WESMAR" brand & they are in Seattle area & it is very HD commercial grade unit & it has been excellent for me for well over a decade of heavy usage.

Probably a 8 inch tunnel would be right size, I recommend a Dual counter rotating 8 inch props style & size. Get Tunnel as low under the water line to reduce cavitation & effectiveness.

Get a Battery to battery 12-24 charger to keep the two (or four) 24-volt thruster battery recharged. I use only group 31 sized starter - AGM batteries & do a Series / Parallel wiring set up to get the 24 -volts with 4 group 31 AGM starting batteries to give me the power for what I needed.
NOTE? 2 can work as well as the 4 , just a little shorter running time endurance.

Plus, with the B to B charger, it tops them off after the house batteries reach full charge when under way or when recharging at dock or with gen-set. So, Keep it simple.

Good Luck.

Alfa Mike

Agree 100%. We have WESMAR 13 HP bow & stern thrusters on Blue Sky (35000 lb NT42) and they have worked flawlessly since installation in 2014. Pretty much the exact same setup as Alfa Mike mentions. I have laid on those thrusters for extended lengths of time and they have never cut out.
 
I've had two Side Power thrusters on my boat for 10+ years now and never had a problem with either one. I change the sacrificial anodes on them every year. The company has a long history and parts seem to be widely available (in Europe, anyway) -- even for older models. Further, I have never heard or read a bad comment about Side Power.
 
Have there been any real improvements in thrusters over the years? Excluding proportional controls. Maybe a bkk lol add redesign years ago.

But an electric motor is an electric motor?
 
I like the variable speed. I hardly ever go full throttle and like the dock holding function.
 
Have their been any other real improvements though in the last 10 or 20 years?
 
Thanks everyone . Bigger is really better , from what you tell me .
 
Thanks everyone . Bigger is really better , from what you tell me .

Absolutely. I would hate to spend the bucks for a thruster and have it be too weak to thrust upwind. I just installed Sideshift thrusters on our boat. I could have gone with the next smaller thrusters and be within the recommended size, but going up didn’t cost much more and the payoff will be forever in having the bigger thrusters..
 
Once you get beyond plastic and under-powered, the quality of most thrusters is good. I'd start by going to the boat manufacturer and asking what they've used successfully. Much of your decision will depend on the boat and available space. Sidepower, Vetus, Wesmar, and Sideshift have been mentioned and all four are quality. Do keep in mind, Wesmar has undergone an ownership change.

However, you may be limited in a used boat and there are some good external mounted thrusters available. Yachtthruster seems to lead that group, but I haven't had experience with them.

My personal preference for a boat your size is Sidepower.
 
My boat came with bow and stern Sidepower thrusters. I thought I should comment on the plastic prop which are standard on my bow thruster, the stern is a lower power thruster and the prop is metal.

Couple season ago I broke the sheer pin on the rear thruster by accidentially switching directions too quickly on the thruster. The controls are supposed to prevent this but they did not. It also happened once to the previous owner. The sheer pin is not located at the prop but at the motor output, so it is changeable from inside the boat while in the water. Depending on accessibility and space, this can be easy or a real pain.

This season a dock line was dropped and got sucked into the bow thruster and stopped it. Once docked I went into the water and cut it free. It was too murky to see anything, but I was able to get it cleared ok. The thruster then continued to work the rest of the season. When I hauled the boat, I found 2 of the 5 blades missing from the prop. Removing the prop, there is a pin like you'd expect on a small outboard but it did not break. It's pretty hefty and the manual refers to it as a "drive pin". Point I'm getting to is that I think the prop is designed to break if it gets jammed up. Easy and cheap to replace, easier than replacing the pin if that had broken. So in this circumstance, I was glad to have a plastic prop. Something has to give if a thruster gets jammed. Do most rely on sheer pins? What is the downside of a plastic prop for a truster?
 
I have a Wesmar on my bow and that thing "jumps" the bow in 20-25 knot winds...
I added a stern thruster when I bought the boat. Looked into Wesmar but the cost was a BIT more than I wanted to pay... :(
I did buy the biggest size that Lewmar had (in 12v).
When I went to wire them up is when I realized the bow was a 24v which explains the power that thing has!!!
Knowing that after I had already purchased it caused some "interesting" and creative wiring... if I had known I would've def got a 24v for the stern also...
My suggestion, get 24v, as others stated, wire up 2 sep batteries in the bow, cuts down wire runs... also get the next size up or that makes sense!!! :)

Side-note, I had sideshift on a previous boat. While costs and install are a bit easier.... the tunnel design on a boat your size will have way better results...
 
We have been in the water for a year with our Mainship 390 single engine w/ Side Power 9 HP bow thruster. We really like it, and have no problems.

However, if I was starting over, I would definitely be putting separate batteries up front OR using 24 volts OR both!!!
The voltage drop is "extreme" in my opinion: System Voltage goes down to 8-10 VDC. That can't be good for a battery bank even in short bursts. It does not reboot my electronics (unless I have a battery bank problem.) That's kinda where I draw the line.

So, it is not bad enough to fix the theoretical "issue" now, in that it does actually work well.

However, if I ever have an excuse to change it out, this system will be improved upon.

So, my free advice: take advantage of this opportunity!
 
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I personally would avoid Wesmar. I purchased stabilizers through them 2 years ago (stabilizers are significantly more expensive than thrusters). Ugly experience in tech support. I understand they changed hands a couple years prior so that may have something to do with it.

It will be a cold day in hell before I recommend Wesmar.

Peter
 
Lewmar bow thrusters

You can read about my thruster problems here:

https://www.trawlerforum.com/forums/s31/damage-lewmar-bow-thruster-57997.html

Short summary>

Had the thrusters installed June 2018
Mar 2020 I noticed a different type of noise and no thrust. COVID madness starts
I hauled out May of 2021 and noticed the missing thruster is missing not just the propeller like I assumed but the whole spindle
Finally I got a new thruster in Sept 2021 after the installer complained to Lewmar distributor
Boatyard that did the install and negotiated a new thruster from Lewemar distributor suggested hauling in the spring of 2022 to install.
 
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Our Side Power has served us very well.
 
I went with Sideshift, bow and stern, with a 24v AGM battery bank near each unit. The two banks share a 2-bank charger. This setup has worked well on our 42 foot express cruiser.

One thing I found valuable was reaching out to the manufacturers. Sure, they have a sales job to do but I felt like I got sound advise each time.
 
I would avoid Lewmar. The PO installed a 185 Tunnel Thruster. It works well. However, the electronic controls have been a real problem. Currently on my third black box control unit.. Their new control system is supposed to correct all the issues but a simpler system like my ABT bow thruster that doesn't have an electronic controller is much more reliable.
 
Here's a novel design worthy of consideration

Here's a novel bow thruster design worthy of consideration. Merry Merry
 

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Irish Lady has a 1987 era Vetus that has been problem free for the 7 plus years we’ve owned her. It’s a little small for the job at 4kw but that’s not the bt’s fault.
 
Check out DockStar - we had two on our 34' CHB Trawler and it could spin on a dime, hold the boat against the slip, easy to install and MUCH less cost than other brands. No extra batteries, wiring etc.

https://www.dockstarthrusters.com

We have a few owners in our area from 34' to 44' that have DockStars.
 
I have a 5HP Wesmar which is anemic on the Nordic 42. Only useful when almost dead calm. The 42 handles well with rudder, prop walk and spring lines so the bow thruster is mostly unused. 10 HP is the min for this size boat.

Tom
 
Have both stern and bow thrusters on my NT42. Have to say I’m truly impressed by your boat handling skills given what your saying. Wonderful to hear as it gives me something to look forward to as my experience with my boat increases. Will agree back and fill is most remarkable with this boat. Can spin with not changing position to an amazing degree. Find it easier spinning to starboard. Coming in without someone on the dock brings the stern right in allowing easy disembarking for a line handler. So like port to. Think 15 hp for the bow and 10hp for the stern is the minimum. Bow likes to blow off.
 
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