36 foot trawler stern thruster question

[Tomkoncius]

I have a single engine trawler with a bow thruster (under powered). I am considering adding a stern thruster any recommendations?

 

[Action]

Tomkoncius, this is the "Welcome Mat" forum.
Glad to have you since June 2001.

The question you ask, I am totally unqualified to answer.

And I would suggest creating a thread in the "General Forum" or the "Power Systems" forum. You might get more replies there.

Good luck.

 

[Comodave]

We put both bow and stern thrusters on our current boat and love how easy it makes docking. Some will say just learn how to handle your boat. I taught boat handling for 30 years and find it is nice to have the thrusters. You should learn how to dock the boat with and without the thrusters anyway. But they sure beat rushing around trying to get the lines in place etc. we look at the thrusters as lengthening our boating life as we get older.

 

[PhilPB]

I have a single engine trawler with a bow thruster (under powered). I am considering adding a stern thruster any recommendations?

Is the battery for your bow thruster holding a full charge? Due to a charger issue, my battery wasn't charging and as the battery discharged the thruster sounded normal but became useless. The charger was malfunctioning so the thruster outfit put in a new charger and battery. I can now move the bow just as it was brand new

 

[Comodave]

Also check each and every connection in the electrical path and make sure all connections are good and tight. You can easily loose voltage on bad connections and low voltage will make the thruster ineffective.

 

[RCook]

FWIW, our Nordic Tug 37's Sleipner SE80 stern thruster works like a charm. It's powered by a G31 AGM battery with 3 feet of 2/0 cable to the thruster.

The SE80 was just installed last August to replace an SP75, which worked very well for 21 years.

21 year old bow thruster (SP95) is also excellent. It shares a parallel pair of G31 AGM's with the windlass.

The batteries are charged via ACR's which connect them to the house bank. Starter bank likewise.

 

[Takeitesea]

Added a stern thruster to my Monk 36. Makes a great difference. Put a Side Shifter made in Canada. Installed because it did not need any below water drilling. One hole the size of a silver dollar for wires. Very happy with the unit
Don
Take It E-Sea

 

[Comodave]

Added a stern thruster to my Monk 36. Makes a great difference. Put a Side Shifter made in Canada. Installed because it did not need any below water drilling. One hole the size of a silver dollar for wires. Very happy with the unit
Don
Take It E-Sea

We did SideShift thrusters also. We didn’t have room inside for traditional thrusters. We have been very happy with them.

 

[Bob328]

I have been delivering boats for many years and learned the importance of using prop walk and honing your docking skills. I now own a Marine Trader with bow and stern thrusters. It is wonderful. It allows you to look professional when docking and takes so much stress off the captain and crew. The combination of bow and stern thruster allows full control in very tight docking situations with adverse wind and current. As Dave says, as we get older we appreciate any tool that allows us to continue our boating passion. We have side power thrusters with a remote that allow us to move about on the fly bridge so we can get a better look. Worthwhile investment, for sure!

 

[Choices]

Thrusters save transmissions. Having a thruster reduces my docking shifts to about 4-5, versus no telling. I only have bow, and would love a stern. Can't imagine the ease.

 

[PhilPB]

Thrusters save transmissions. Having a thruster reduces my docking shifts to about 4-5, versus no telling. I only have bow, and would love a stern. Can't imagine the ease.

I'm down to 1-2 and even look like a pro now. Before the thruster it could take forever trying to get it in the slip. Even using prop walk, on a windy day I had balloon walk all over. Also, my boat is rather light so the thruster puts it where I want it to be.

 

[AndrewAdams]

Stern Thruster vs articulating rudder

You might consider an articulating rudder, which would allow you to direct your prop wash at 90 degrees to your centerline. Makes for a very powerful thruster, and also helps the rudder response in other maneuvers. It helps my autopilot handle tidal swirlies with ease.

It would not help if you were in reverse, though. My boat's quite heavy, so it takes a bit for 'thruster-type' throttle usage to begin to move the boat forward, but that does happen eventually. But the stern leaps to port or starboard when I've got the wheel hard to either.

There was a kit for my boat, there might also be one available for yours.

 

[Laurie]

We had DockStar thrusters on our 34' CHB (single Lehman 120) and it made docking in any conditions a breeze. Reversing into our slip became a pleasure instead of a test of skill. We looked at Sideshift too, but the Dockstar is removeable, rechargeable and radio controlled. See dockstarthrusters.com

 

[Gary Brickell]

Love my new Stern Thruster

I added a SideShift stern thruster ST-340 on the swim platform of my single engine (no bow thruster) trawler this summer and it has made a great improvement in handling. I don't have a bow thruster just a single inboard and a rudder. I can now pivot on the spot 90 degrees in five seconds.

For making tight turns and pinpoint docking in the marina you can't beat the advantage of a stern thruster. For fighting a strong side wind force a bow thruster is better. If you can only afford one determine which is the most frequent challenge; side wind or pivoting into a slip. I installed the SideShift stern thruster and connected it to my two AGM house batteries, in one day DIY. The total cost was $5k cdn about $3,800.us Bonus it also comes standard with a lanyard remote control.

 

[HopCar]

Real men don’t need no stinking thrusters!
Just kidding! I’m in favor of anything that makes boating easier or safer. Thrusters check both those boxes. I’ve owned three single engine inboard boats and many times I wished I had thrusters. I suggest you try not to use them unless you have to. That way when the thruster fails you’ve had plenty of practice.

For a stern thruster I’d probably go with a Side Shifter.

 

[crusin_canuk]

We, too, have a Monk 36. It came with a Vetus 12V 55 kgf bow thruster. I found it to be a bit under powered for the conditions here in the Maritimes, so I upgraded it to Vetus' newer 12V 75 kgf model (BOW7512D), and added the same thruster as a stern thruster, each with their own battery bank and charger. The only problem I encountered was with the stern thruster not being far enough below the water line on the transom. This is simply because of the Monk's design. Fortunately, the addition of stern tunnel extensions resolved the issue of air getting into the tunnel. I've been using them for a couple of years now and been very happy with them.

One suggestion, though. If you can, go for an extended run time or hydraulic model. The three minutes of run-time you get with the standard model can go quickly on a windy day.

 

[Comodave]

We put SideShift thrusters on our current boat. They were a simple DIY installation. I had contacted 2 mobile thruster installers for Sidepower thrusters. The price for both installed was $25K. But then we took possession of the boat and I started looking around for where the thrusters would have to be installed. I found that in order to fit them into the boat. For the bow thruster I would have had to relocate the forward cabin A/C. In order to install the stern thruster I would have had to relocate the water heater, water lift generator muffler and about 5 water hoses and move them to the only open area in the stern and thereby making the area completely inaccessible for maintenance. So I found the SideShift thrusters. They were about $10K including the 4 necessary batteries. So I saved $15K and had new upholstery done instead. My wife and I did the bow thruster install in a day and a half. My neighbor and I did the stern thruster install in a day. And I didn’t loose the interior room. They came with wireless joysticks and a wireless fob remote control. We have had them for 2 years now and are completely satisfied with them.

 

[Mainship Pilot]

Been running boats all my life, never used thrusters before,but my latest boat had both Stern and bow. Never touch the wheel anymore, thrusters do all the work! 2 AMG Group 31's for the thruster bank.

 

[philmitch]

Love my new Stern Thruster

I added a SideShift stern thruster ST-340 on the swim platform of my single engine (no bow thruster) trawler this summer and it has made a great improvement in handling. I don't have a bow thruster just a single inboard and a rudder. I can now pivot on the spot 90 degrees in five seconds.

For making tight turns and pinpoint docking in the marina you can't beat the advantage of a stern thruster. For fighting a strong side wind force a bow thruster is better. If you can only afford one determine which is the most frequent challenge; side wind or pivoting into a slip. I installed the SideShift stern thruster and connected it to my two AGM house batteries, in one day DIY. The total cost was $5k cdn about $3,800.us Bonus it also comes standard with a lanyard remote control.

Hello Gary,
Can I ask the installation process for the install of the ST-340 on your swin platform? I'm going to install an ST- 350 on our 41' and not going through the transom would be way easier.
Thank you!

 

[Comodave]

Going through the transom isn’t too much work, just 4 bolt holes and two holes for the cables. You would still need to have the two holes for the cables either way.

 

[philmitch]

Thank you Comodave. It looks to be a pretty simple install in dry dock but I was intrigued by the install through the Swim Platform, as it sounds like it could be done in water.

 

[Comodave]

You can do it through the transom while the boat is in the water. All the holes are above the waterline. The only real issue would be holding the thruster itself up while doing the install. Maybe have to tie a rope on it in case you loose your grip on it. But almost all the install work is the wiring on the inside. As to the thruster itself, installing it is as simple as drilling the 4 bolt holes and caulking the holes. Then insert the bolts and tighten them up. Then drill the 2 cable holes and inserting the cables and then caulking the holes. All the rest of the work is mostly just wiring up the batteries, fuse, battery switch and the reciever for the joystick signals.

 

[philmitch]

Thanks again and now I see that's the case!
Your help is appreciated!

 

[Gary Brickell]

Hello Gary,
Can I ask the installation process for the install of the ST-340 on your swin platform? I'm going to install an ST- 350 on our 41' and not going through the transom would be way easier.
Thank you!

Hello, I beached my trawler at a sand beach near our marina on a calm mid week day to avoid passing boat wakes. and did the bolting through the swim platform single handed, while standing in water about 3.5'deep. With a battery drill I drilled the cable pass through holes about 8" above the waterline.
Sideshift provides excellent clear instructions and premium silicone couching. You may need to order the optional extension tube, to get the correct depth. For mine I ordered the 12" one then custom cut it down and re-welded it to 8". You want the top of the props to be no less than 5" beneath the surface.