sterndrive and sternthruster together on one boat

[Julia-Kristina]

Hi
I am new in this forum, I am living in Germany, and I obviously had put my first item in the wrong department, to the sailors, as Greg wrote me.

Since it is a question concerning motorboats I just put a 2nd mail here - who may be interested can have a look in the sailor's department where you find my original and more detailled mail.

Why do I enter into an English forum ?

Because we have an English boat which is quite rare in Germany and I hope to find some people here with experience on this type of boat.

Short abstract of my problem:

Boat Relcraft topaz 29, built in 1980, approx. 29 feet long, stern drive, bow thruster, very flat hull under water, extremely sensible to wind and current, she glides like on ice then.

The boat is laying in the north of Berlin, we are living in the south, in Bavaria, 500 km away, so I do not have too much time to exercise with exception of holidays.
And I want to be sure that everybody who will be steering the boat will be able to get it into any harbour and under any wheather conditions without damaging other boats.

My idea was to install an additional sternthruster, and I got an informative answer of Greg already in the scuttleboat forum.

I am very interested in getting some more advices of people who may have experience with the same problem.

Thank you in advance,

kind regards from Germany,

Julia- Kristina

 

[Elza_Skip]

Hi Julia, you are most welcome

I would think that as you already have the bowthruster you would not get much more advantage with a sterrn thruster as you can use the drive to move the stern sideways

Also stern thrusters are usually mounted on the transom and this would not be possible with a stern drive

 

[PaulGooch]

Your original post was moved to the motor boat forum, it's a few threads below this one. The replies you had previously, were made here.

 

[Julia-Kristina]

Thank you for your welcome

Hi Julia, you are most welcome

I would think that as you already have the bowthruster you would not get much more advantage with a sterrn thruster as you can use the drive to move the stern sideways

Also stern thrusters are usually mounted on the transom and this would not be possible with a stern drive

Hi and thank you for your mail.
I already got a lot of interesting answers already in the forum concerning this problem which give me a lot of possibilities to think about during wintertime...
I did not imagine that a flat underwater hull like on our boat (Relcraft topaz 29 ft ) makes such a difference when it is windy compared to a displacement boat with a deep keel.
But nevertheless, we love the boat !
Thank you and kind regards from Germany,
Julia- Kristina

 

[Julia-Kristina]

Your original post was moved to the motor boat forum, it's a few threads below this one. The replies you had previously, were made here.

Thank you, Julia-Kristina

 

[aquatom]

Sidepower do a stern thruster for use on twin stern drive boats. Have a look on there website.

 

[Julia-Kristina]

Hi Aquatom,
thank you for your message but I have a single sterndrive, with one propeller.

It seems that the easiest way could be to install a stronger new bowthruster and to use the old one as a sternthruster.
But then it has to be fixed on the right or left side of the sterndrive, outside at the stern, I was told !?

Fortunately I will have the whole winter to find the best solution.....

Kind regards from
Julia-Kristina

 

[Elessar]

Hi Aquatom,
thank you for your message but I have a single sterndrive, with one propeller.

It seems that the easiest way could be to install a stronger new bowthruster and to use the old one as a sternthruster.
But then it has to be fixed on the right or left side of the sterndrive, outside at the stern, I was told !?

Fortunately I will have the whole winter to find the best solution.....

Kind regards from
Julia-Kristina

You will probably find that the old bowthruster will be too physically big to fit as a sternthruster as the tunnel you will need will be huge. You'll probably need a smaller diameter thruster - depends on what you've got now of course.

Ye you will need to offset it and fit ears on the tube to try and get the top of the tube deep enough in the water.

We have fitted a sternthruster to a (twin outdrive) boat, and it costs as much to install as a bowthruster. You'd think bolting a tunnel on the stern would be quicker than putting a tunnel through the bows of a boat but there is far more to it than meets the eye.

You will be looking at over 3000 euros by the time you've installed your sternthruster. I think 2 days boat handling training would save you that 3000 euros.

 

[Julia-Kristina]

Hi Elessar,
thank you for your letter. Maybe one could try to fix the old bowthruster at the stern ,but outside ? Should be cheaper since less work, no ?

I will have to ask somebody of a shipyard I think.
Fortunately I will have some more months to find the best solution.

Of course you are right that I have to exercise.
But the problem is really that starting from a certain level of wind any exercise and any manoever does noth help anymore, she is floating like on ice...
But we love her nevertheless !!

Kind regards from
Julia-Kristina

 

[Elessar]

Hi Elessar,
thank you for your letter. Maybe one could try to fix the old bowthruster at the stern ,but outside ? Should be cheaper since less work, no ?

I will have to ask somebody of a shipyard I think.
Fortunately I will have some more months to find the best solution.

Of course you are right that I have to exercise.
But the problem is really that starting from a certain level of wind any exercise and any manoever does noth help anymore, she is floating like on ice...
But we love her nevertheless !!

Kind regards from
Julia-Kristina

What you do is buy an external tunnel which bolts to the transom. This in itself will cost 2-300 euros. The prop is in that but the motor is inside the boat - you make a big hole in the transom where the tunnel bolts on and the motor goes horizontally.

You have to seal the transom all around the hole you made to stop water getting into the bare wood, and fabricate a support for the horizontal motor. Often the thickness of the transom means you need to make it thinner where the motor is, which all has to be re fibreglassed over.

The motor has to stay dry so a waterproof coffer needs to be fabricated around the motor to protect it from bilge water.

All of the above needs doing where there is inevitably very poor access and all in all is as much work as putting the tunnel through the boat at the bow.