Bow or Stern Thruster

[IG 30]

Hi All, I have a 30ft island gypsy with a single 120 Lehman, if you know these boat then you will know they are obsoletely hopeless in reverse if there is the slightest wind or current, I have just moved from a mooring to a pen in a marina and reversing into the berth between two boats is all most impossible.
My question is about adding a thruster either bow or stern and the advantage in assisting in the reversing issue, I only want to add one thruster,
Thanks

 

[O C Diver]

Have you thought about taking a couple of days of instruction from a professional training captain. Often times they can show you techniques to dramatically improve your close quarters handling. This in no way is ment to disparage your boat handling skills, but you don't know what you don't know.

If I were going to add only one thruster, it would be in the bow. With some practice, you should be able to back down a fairway using the bow thruster to steer the boat. IMO, the stern thruster is less effective when backing and more effective pushing the stern over.

Ted

 

[psneeld]

I always have to say it depends when I can't handle the boat and see the actual conditions one normally docks in.....

But I agree with Ted that a single can somewhat control the stern with engine and rudder (if not improve rudder design which is cheap in the big scheme of things) so a bow thruster helps with both ends. So does better technique which is why Ted recommended training.

In some situations and some boats, a stern thruster can do the same, but without hands on experiences, I usually go with the bow thruster.

Too bad they are way more expensive unless you do the install

 

[Hippocampus]

Generally speaking bow thrusters are deeper in the water than stern ones. So for the same hp, gearing and prop size produce more effect. Also prop tunnel is generally longer and straighter so more effective.
Currently have both and without a doubt bow moves the boat more. Given a boat is a rigid structure unless you want to go sideways it doesn’t matter which one you use to rotate the boat. If money is short go for the bow.

 

[IG 30]

Thanks for your input, I have owned boats all my life however I have never come up against a boat like this, reversing into a berth wind or tide has never been much of an issue but the IG has no control at all and they are well noted in my area for this reason.
I try to use the prop wash forward to swing the bow then short burst in reverse to start back momentum and to keep the turn but no it will not.
I know what needs to be done.

 

[PhilPB]

Speaking from experience, a bow thruster was the best upgrade I had installed on our single screw 34 Mainship. The boat easily gets blown around with the wind, being it's rather light and bimini, skirts, etc. The thruster makes it amazingly easy to maneuver in many situations, especially backing into my slip with winds over 15 mph. It was the best $10k I have spent on the boat.

 

[Capt Mike]

I have a single screw Mainship 400 with a bow thruster. My marina is so compact that with any wind I could not get into my slip without the bow thruster. I take advantage of prop walk to get the stern where I need it to get into my slip.
I do plan on adding a stern thruster this winter as we plan on doing the great loop in the coming years and I feel it will be very helpful getting into marinas where I am less familiar with the layout and I can’t always get a port side tie.
So my input for you would be to definitely go with the bow thruster if you are choosing between the two.

 

[Barking Sands]

Just to add a reference point for you, I have a Tung Hwa 31 with a Perkins 120 hp engine. It is essentially a copy of your IG. It too is terrible backing in anything more than light breeze or current.

However, when I bought it it was equipped with a Dickson Stern Thruster. It is a hydraulic thruster that is quite powerful (especially for this size boat. Output is proportional to engine rpm.

When I first got the boat I always backed in without touching the thruster since I was admonished by a well seasoned slip mate to not overuse the thruster and hinder gaining experience backing without any aids. To this day his voice runs through my head every time I approach the slip and just make the turn outward to line up the aft "One day you wont have that fancy thruster to count on when it breaks. You better know how to back it in without it in poor conditions"

I did that a few times. Then one day it was a bit windy out and just used the thruster. Zipped it right in within inches of the intended target. Its like having a superpower.

Of course I still hear my old slip mate admonishing me:lol:
But it sure is nice to have that stern thruster and raises my confidence 10 fold.

 

[Comodave]

We put a stern thruster on our last boat because the only helm was on the flybridge and by the time I would get down to handle the stern line the stern would blow off the dock. So to save trips back up and down I installed a stern thruster, worked great. On our current boat my wife said she didn’t want to buy it because she couldn’t go forward easily to handle lines. I told he that we would put a bow and stern thruster on so she wouldn’t have to go forward. There are a couple of mobile thruster installation companies that would do both for about $25K. I bought the boat and scheduled the thruster installation. But after buying the boat and poking around I found that the bow thruster tunnel would make me move the forward A/C and the stern thruster would make me move the water heater and the genset muffler along with about 6 hoses. I canceled the thruster installation. I found a company called SideShift. They make bolt on thrusters. The installation is very easy. Took my wife and I 1.5 days to do the bow thruster and a friend and I one day to do the stern thruster. They are 24 volt thrusters so I had to buy 4 batteries and 2 chargers. Total cost was under $11K. Now she stands in the stern and puts a stern line on first. We keep permanent bow lines tied off at the aft spring cleats. We do a stern line and walk forward on the dock and untie the bow line and secure it to the dock.

 

[Arc]

I don’t care who or how seasoned you are , thrusters make life easy . I don’t need to be challenged every day. Get them installed and enjoy boating.

 

[Comodave]

Yes, it really gets me when people say just learn how to handle your boat and you don’t need thrusters. I have taught boat handling for 30 years and did crew and coxswain testing for the CG for probably 18 years. I can handle a boat. But we turned 70 this year and we are not as nimble, by far, and strong as we used to be. So if having thrusters means we can boat for more years then we will have thrusters. Maybe we can get another 10 years or so of boating that we couldn’t get without thrusters. So the naysayers can kiss my, you know what…

 

[Barking Sands]

I don’t care who or how seasoned you are , thrusters make life easy . I don’t need to be challenged every day. Get them installed and enjoy boating.

These days I move more and more towards the "easy life".

 

[Hippocampus]

Think one should use ALL the tools available. Commonly use back and fill to line up. Both thrusters to pivot and move sideways. Think in wind and or current using thrusters in combination with wash or walk makes sense. Also use a magic spring line. Don’t agree with purist nonsense. Rather learn and use all the tools available.

 

[jimdavi]

Have large bow and stern thrusters. Although I don’t reach for them unless I need-they take the stress out of almost any situation. Love ‘em …

 

[Jeff F]

I try to use the prop wash forward to swing the bow then short burst in reverse to start back momentum and to keep the turn but no it will not.
I know what needs to be done.

Can you turn the other way?

A stern thruster would undoubtedly help with the challenge you describe. A bow thruster might help as well.

My thoughts echo Ted's. The recommendation on training is a good one. You shouldn't view it as a challenge or slight.

My own experience with a few single engine boats is that with a bow thruster and expertise/practice you can learn do any maneuver proficiently. I wouldn't say the same for a single with a stern thruster only. But I've never driven an IG30.

Sent from my moto g play (2021) using Trawler Forum mobile app

 

[Choices]

We have a single GB36. Bow thruster saves wear and tear on the tranny. It is so much easier, my goal is to dock in less than four shifts. A stern thruster would be awesome, but I can put it where I want with the bow. Mine really won't prop walk for crap. Just king of moves a couple feet.

 

[Jeff F]

Too bad they are way more expensive unless you do the install

I'm hanging around in Ontario cottage country this summer, and have seen increasing numbers of boats with external bow thrusters like these guys
https://sideshift.com/products/monohull-bow-stern-thrusters/

I'm still not sure I'd want one, but they seem to be meeting the need for decent functionality and inexpensive DIY. Better on a planing boat, probably.

I've talked to a couple of people who chose stern thrusters because they were cheaper. Generally a mistake, I think.

Sent from my moto g play (2021) using Trawler Forum mobile app

 

[Comodave]

We put a stern thruster in our last boat and it was awesome. I had to climb down from the flybridge and by the time I was down the stern had blown off the dock. So I would go back to the helm and move the stern close and hurry faster. The faster I tried to go the more likely I was to fall. So I put the stern thruster in. Wonderful.

 

[djones44]

Thrusters are a big intrusion that invite misery, better to understand prop walk. I removed my stern thruster, with its big batteries, they only last for a limited time. I learned that hard to port my boat rotated counter-clockwise when alternating forward and reverse. In the tightest pocket I have just gone back and forth, rotating gradually, until the boat was pointed. Then just went straight ahead, anywhere. Docking in reverse is very susceptible to wind.

 

[psneeld]

I'm hanging around in Ontario cottage country this summer, and have seen increasing numbers of boats with external bow thrusters like these guys
https://sideshift.com/products/monohull-bow-stern-thrusters/

I'm still not sure I'd want one, but they seem to be meeting the need for decent functionality and inexpensive DIY. Better on a planing boat, probably.

I've talked to a couple of people who chose stern thrusters because they were cheaper. Generally a mistake, I think.

Sent from my moto g play (2021) using Trawler Forum mobile app

Have never seen one or have experience with one so I really can't comment.

I was just commenting on the cost of a traditional tunnel thruster....

 

[Comodave]

I have 2 of them that I put on our current boat. They are simple to install and are relatively inexpensive, about $11K for both and I did the install. They may work a bit less effectively because they are not in a tunnel but I am quite satisfied with the performance. Mine are 24 volt so I have 2 chargers for them that are included in the price I stated. I literally couldn’t do traditional thrusters because of what would have had to be removed or moved around. It would have eaten up the little bit of access space that I have for maintenance.

 

[psneeld]

I would still want some hands on experience before I bought one... I do have lots of experience with the conventional tunnels.

 

[Barking Sands]

I made this quick overview of the Dickson hydraulic stern thruster today since there is very little info on them.

https://youtu.be/oV4mVbDxX1s

I need to add some weight in the aft:lol: Damn thing is cavitating. I just need to fill my water tanks

 

[Jeff F]

Yes, it really gets me when people say just learn how to handle your boat and you don’t need thrusters.

It gets me when able bodied people are led to believe that bow and stern thrusters are necessary for getting a 30' boat in and out of a slip. Need is a very subjective term.

I guess we all have things that set us off. But this isn't relevant to the OP's question - picking one, bow or stern, which will it be?

Sent from my moto g play (2021) using Trawler Forum mobile app

 

[SteveK]

The OP should get a stern thruster to allow backing up adjustments to go straight.

 

[GB32Patience]

GB32 Thruster approach

On our GB32 we are glad to have the bow thruster but for the stern, although an unpredictable "walk" a "hard over" port or std. will "kick" the stern with a burst of throttle... works as a fine stern thruster.

 

[BruceK]

Thanks for your input, I have owned boats all my life however I have never come up against a boat like this, reversing into a berth wind or tide has never been much of an issue but the IG has no control at all and they are well noted in my area for this reason.
I try to use the prop wash forward to swing the bow then short burst in reverse to start back momentum and to keep the turn but no it will not.
I know what needs to be done.

You are in good company,I watched two guys I think were servicing it, try to reverse an IG30 into a pen, without success. Hearing from 2 marinas away, a loud "every time I reverse the %*&# walks to port"! I think one got on the dock, attached a line, and helped drag it in.
Think I`d start with a bow thruster, more help generally, but SteveK`s suggestion makes sense. Ask the marina about dealing with their local conditions?
Thank goodness my IG 36 had twins.

 

[markpierce]

rudders can serve as stern thrusters ... bow thrusters are handy

 

[fgarriso]

We use thrusters but have twins. So we don't have the same prop walk effect. My wife and I are 75 years old and what made her the most nervous was docking in tight quarters or at a strange slip or dock. I say if you need a stern thruster then get one and use it. Also don't be hesitant to get some training on using your single screw. Some old guys "Captains" are sure to remember handling single screws. But if you opt for training do it on your boat.

 

[mvweebles]

Yes, it really gets me when people say just learn how to handle your boat and you don’t need thrusters. I have taught boat handling for 30 years and did crew and coxswain testing for the CG for probably 18 years. I can handle a boat. But we turned 70 this year and we are not as nimble, by far, and strong as we used to be. So if having thrusters means we can boat for more years then we will have thrusters. Maybe we can get another 10 years or so of boating that we couldn’t get without thrusters. So the naysayers can kiss my, you know what…

Agree 100%. There is no question that thrusters make a boat more maneuverable. For many recreational boaters, docking and undocking is the most stressful part of a day on the water, myself included. Returning in the afternoon when winds have piped up comes to mind.

Some boats just don't respond as well as others. Some have a lot of prop walk, some have very little. Many slip configurations have challenges. Some boats and operators are well suited to springlines, most are not.

A maneuverable boat gets used. That's a good thing. Thrusters greatly expand the safe-zone of operation. Also a good thing. They reduce stress. Yet another good thing.

In the end, a $10k thruster can easily mean a $200k boat (perhaps much more) gets used more. In boat-logic, that's a really strong ROI.

Peter

BTW - my vote for OP is a bow thruster. Rudder provides some modicum of maneuverability at the stern. Bow is often less controllable due to being lighter and a longer lever arm from prop/rudder