Side Shifter Stern thruster

[Lasse]

Hi,

Does anyone have any experience with side shift stern thruster?
http://www.sideshift.me/
I am about to fit one on a 40 foot Motor boat 15 metric tons.
The boat have exhaust outlet near the bottom of the boat, this casues some Exhaust buubbels and some “experts” have mentioned that this might be a problem as the thruster could suck in air.

All input are most appreciated.

/Lars

 

[RogerRat]

Hi,

Does anyone have any experience with side shift stern thruster?
http://www.sideshift.me/
I am about to fit one on a 40 foot Motor boat 15 metric tons.
The boat have exhaust outlet near the bottom of the boat, this casues some Exhaust buubbels and some “experts” have mentioned that this might be a problem as the thruster could suck in air.

All input are most appreciated.

/Lars

Hi Lars,
Welcome to the forum, you could tell us more in your intro. to assist better:


Look at this thread, 'Interesting Bow Thruster' and the picture at post #10
http://www.ybw.com/forums/showthread.php?390641-Interesting-Bow-ThrusterThese side thrusters look terrible, will pick up all sorts of debris, potentially hazardous to swimmers if deployed accidentally. Generally, not necessary if you have a bow thruster. Sucking air is not going to be an issue but in some tidal waters sucking in weed, flotsam and other jetsam in closed berths could be.


RR

 

[Lasse]

Ok, here are the answers

1.What is your 40 footer? This will tell us what type of hull you have.
Boat type Storebro 400 with a semi planning hull

2. Is it a Displacement, Sports (like the Searay in your link) or Flybridge boat. This will tell us the likely amount of windage and underwater resistance you have.
The boat has a Fly bridge with a semi planning hull weight 15 metric tones. Draft is moderate approx. 1 m + rudder.

3. Does the boat have outdrives or shafts? The Searay in the video is probably on outdrives (legs) so definitely does not need a stern thruster.
This boat has two TAMD71 motors with straight propeller shafts.

4. What level of experience do you have? Years and boats owned? Easier to advise if we know your capability.
More than 20 years of experience with larger Motor boats above 35 feets.

5. Where are you boating? Conditions and usage? Again useful.
Open sea in the Baltic, Sweden, Finland, and the other Baltic country's

This is purely a technical question/matter. The questions is if someone has experience with a Stern Thruster where the exhaust from the motors is close to the thruster and particular if some one has experience with a side shifter that has open propellers with no tunnel. Other type technical of experience in this matter is appreciated.

Opinions if or if not the thruster is needed on this boat type is uninteresting.

/Lars

 

[SEARANGER ANCASTER]

Hi,

Does anyone have any experience with side shift stern thruster?
http://www.sideshift.me/
I am about to fit one on a 40 foot Motor boat 15 metric tons.
The boat have exhaust outlet near the bottom of the boat, this casues some Exhaust buubbels and some “experts” have mentioned that this might be a problem as the thruster could suck in air.

All input are most appreciated.

/Lars

For all the time they will be running , I would doubt the exhaust bubbles would be much of an issue
Despite what it says on the website , I would doubt that this has equal or less drag than a traditional tube type thruster ?? Plus it looks like a strap on !

 

[RogerRat]

Hi,

All input are most appreciated.

/Lars

RR

 

[Nick_H]

Well obviously not...:ambivalence:

:encouragement:

Anchored.:disgust:

RR

In fairness, he asked quite a specific technical question about the effect of exhaust bubbles on a stern thruster, so we didn't really need to know his boating history etc. Also, English obviously isn't his first language, so his use of the word "uninteresting" was probably not meant to sound dismissive.

 

[Divemaster1]

Heisan Lars,

Perhaps you could clarify a couple of things ... I presume that your exhausts are similar to these on a 34 ... which are quite close together..

I also guess that this is the reason for choosing a thruster that protrudes beyond the exhaust outlets to avoid restriction in waterflow from thruster. The next question will of course be if the thruster propeller(s) will be on the inside, outside or nearly aligned with the exhaust outlets?

My guess would be that if close to the outlets, there will be a certain risk of interruption, but I could not possibly comment on how much impact this could have...

 

[Lasse]

Ok, here are the answers
Opinions if or if not the thruster is needed on this boat type is uninteresting.

Sorry for my bad English, what I meant is that the question I have is of the technical aspects especially of exhaust bubbles near the side thrust propeller. The rezone for fitting a stern thruster is to move the boat sideways in narrow harbours when mooring.

/Lars

 

[Lasse]

Heisan Lars,

Perhaps you could clarify a couple of things ... I presume that your exhausts are similar to these on a 34 ... which are quite close together..

I also guess that this is the reason for choosing a thruster that protrudes beyond the exhaust outlets to avoid restriction in waterflow from thruster. The next question will of course be if the thruster propeller(s) will be on the inside, outside or nearly aligned with the exhaust outlets?

My guess would be that if close to the outlets, there will be a certain risk of interruption, but I could not possibly comment on how much impact this could have...

Hi Alf,

No we are getting to the core of the question.

The stern on the picture is very similar to our boat. The idea is to fit the Stern thruster horizontal low in the stem facing backwards it will reach out from the exhaust pipes and be mounted slightly above the bottom/keel of the boat. The question is really how far back from the exhaust pipes is needed to avoid to much air in the propeller stream. The mechanics I have talked to have warned that when a normal tube stern thruster is fitted near to the propeller stream it will cause interference with exhaust air coming out. The engines are Volvo TAMD71A 357 Hp and 6,57 litres each so they are producing quit a lot of bubbles idling.

This picture give an idea how the side shift will be mounted:

/Lars