sterndrive and sternthruster together ? Germany needs help !

[Julia-Kristina]

Hello,
I am writing from Germany hoping that an english forum may help me with a problem that we have with our boat...

We bought an old english boat last year, a Relcraft Topaz 29, ca. 29 feet long, built ca 1980. No aft cabin but very spacious cockpit.

She has a sterndrive and a bowthruster which is not very strong.


Now we have problems when it is windy: the hull under water is not very deep and so she glides like on ice when there is a sudden squall of wind.
Last time I could even not leave the harbour because I did not want to risk to damage other boats.

I am a beginner and without routine it is even more difficult.

And yes, I am a woman, please no prejudices concerning women and boatmanship - I try to learn

Now I would like to have an additional sternthruster!

But I was told that with sterndrive you have to mount 2 smaller sternthrusters for the left and the right side of the sterndrive.

The normal solution with 1 thruster would not be possible when the boat has a sterndrive.
This is quite expensive of course and I am wondering if there is another possibility to avoid these maneuver problems with wind and current.

Since our boat is english originally I hope that there are more members in an english forum with experience with this type of boat.

We like the boat very much, specially because of its very big and comfortable cockpit, and we want to keep for many more years. So I have to find a reasonnable solution for this problem.

I hope you can help me,
thank you in advance,

Julia- Kristina

 

[Greg2]

Hi Julia-Kristina,
Sounds like your boat is a motor boat so you may get a better response from the Motor Boat Forum on this site. This forum is mostly used by people with sail boats.

I am not familiar with your make of boat but our first boat was a Princess 32, which had very flat sections on the rear part of the hull and as a consequence she tended to be affected by the merest puff of wind. We had twin engines so it was a bit easier to manage than one engine will be. The thing is to practice - even with one outdrive you still have directional thrust that you can use to your advantage. The general rule is steer before adding power in close quarter manoeuvring and don't use too much power - if you can achieve what you need to by just slipping in and out of gear then that is best. Find some space and play around with the engine and steering so you get a feel for how the boat responds. In particular get a feel for the turning/pivot point on the boat - usually a point about two thirds of the length of the hull from the bow. It isn't like driving a car - when you turn the bow will go the way you want it to but the stern will also move in the opposite direction.

It is not unusual to have difficulties when first handling a boat and if you are a complete novice it is worth getting some training - you will be surprised what difference it makes to have someone show you the tricks of the trade.

With regard to the stern thruster I am not sure that it would be money well spent. As mentioned above, with a sterndrive you already have the ability to direct power where you need it. For example if you put the helm hard over to port and slip the engine into astern (reverse) the stern will move to port. The trick is to slip it in and out of gear so that you get the sideways movement without too much backward movement or the bow moving too much to starboard. You already have a bow thruster to help with the bow.

If you do decide that a stern thruster is needed I am not sure that two will be required. It might not be possible to mount it centrally because of the outdrive but assuming the transom is straight I can't see why one couldn't be mounted offset to the centre.

Personally I would go for learning to handle the boat rather than spending money.

Hope this helps.

 

[Elessar]

Hello,
I am writing from Germany hoping that an english forum may help me with a problem that we have with our boat...

We bought an old english boat last year, a Relcraft Topaz 29, ca. 29 feet long, built ca 1980. No aft cabin but very spacious cockpit.

She has a sterndrive and a bowthruster which is not very strong.


Now we have problems when it is windy: the hull under water is not very deep and so she glides like on ice when there is a sudden squall of wind.
Last time I could even not leave the harbour because I did not want to risk to damage other boats.

I am a beginner and without routine it is even more difficult.

And yes, I am a woman, please no prejudices concerning women and boatmanship - I try to learn

Now I would like to have an additional sternthruster!

But I was told that with sterndrive you have to mount 2 smaller sternthrusters for the left and the right side of the sterndrive.

The normal solution with 1 thruster would not be possible when the boat has a sterndrive.
This is quite expensive of course and I am wondering if there is another possibility to avoid these maneuver problems with wind and current.

Since our boat is english originally I hope that there are more members in an english forum with experience with this type of boat.

We like the boat very much, specially because of its very big and comfortable cockpit, and we want to keep for many more years. So I have to find a reasonnable solution for this problem.

I hope you can help me,
thank you in advance,

Julia- Kristina

Greg offered very good advice.
It is possible to fit sternthrusters to stern drive boats - my company fits them. You can fit one, offset one.
However it is so easy to handle a stern drive boat with just a bit of practice and experience.
A bowthruster on a single engine sterndrive boat is an asset. Upgrading that to a more powerful one would be better spent than adding a sternthruster.
But before any of that spend your money on a day's tuition. It will transform the enjoyment of your boat.

________________

ARC. Antifoul Removal, Epoxy Coatings, CopperCoat

Noisekiller Marine. Automotive acoustic technology now available for your boat

Sail for Fun. Yacht and Motorboat charter

 

[Julia-Kristina]

Julia- Kristina to Greg

Hi Julia-Kristina, Hi Greg

Sounds like your boat is a motor boat so you may get a better response from the Motor Boat Forum on this site. This forum is mostly used by people with sail boats. O.K. next time I will know.

I am not familiar with your make of boat but our first boat was a Princess 32, which had very flat sections on the rear part of the hull and as a consequence she tended to be affected by the merest puff of wind. Very nice boat, it was an alternative for us when we were looking for a boat to buy.

We had twin engines so it was a bit easier to manage than one engine will be. The thing is to practice - even with one outdrive you still have directional thrust that you can use to your advantage.
The general rule is steer before adding power in close quarter manoeuvring
do you mean steer and immediately afterwards add power ? and don't use too much power - if you can achieve what you need to by just slipping in and out of gear then that is best.
Find some space and play around with the engine and steering so you get a feel for how the boat responds. The boat is laying on a lake ( Lehnitzsee close to Oranienburg in the north of Berlin ), so there is enough space to exercise. But in some days the boat will be brought ashore by a crane so I have to wait with exercising until spring :-( In particular get a feel for the turning/pivot point on the boat - usually a point about two thirds of the length of the hull from the bow. It isn't like driving a car - when you turn the bow will go the way you want it to but the stern will also move in the opposite direction.

It is not unusual to have difficulties when first handling a boat thank you for your comfort and if you are a complete novice it is worth getting some training - you will be surprised what difference it makes to have someone show you the tricks of the trade.

With regard to the stern thruster I am not sure that it would be money well spent. As mentioned above, with a sterndrive you already have the ability to direct power where you need it. For example if you put the helm hard over to port and slip the engine into astern (reverse) the stern will move to port. The trick is to slip it in and out of gear so that you get the sideways movement without too much backward movement or the bow moving too much to starboard. You already have a bow thruster to help with the bow.

If you do decide that a stern thruster is needed I am not sure that two will be required. It might not be possible to mount it centrally because of the outdrive but assuming the transom is straight I can't see why one couldn't be mounted offset to the centre Interesting idea, I will ask at the shipyard if this would be technically possible
Personally I would go for learning to handle the boat rather than spending money.
The problem is that on the lake sometimes the wind appears suddenly and is quite strong.
And since we are living in the south of Germany, in Ingolstadt / Bavaria, but the boat is 5oo km away in the north of Berlin, I can not exercise every weekend.

I do not want to risk to damage other boats, so I want to be sure that I - and also our daughters, friends etc - can handle the boat under any wheather conditions. And that's why I had the idea with the stern thruster.
Of course I know that 90 % is exercising, and I will do that seriously, but I want to have a "security guarantee " for the last 10 %

Hope this helps.[

Dear Greg, thank you for your help ! Kind regards from Germany, Julia-Kristina

 

[Julia-Kristina]

Julia-Kristina to Elessar

Greg offered very good advice.
It is possible to fit sternthrusters to stern drive boats - my company fits them. You can fit one, offset one.
However it is so easy to handle a stern drive boat with just a bit of practice and experience.
A bowthruster on a single engine sterndrive boat is an asset. Upgrading that to a more powerful one would be better spent than adding a sternthruster.
But before any of that spend your money on a day's tuition. It will transform the enjoyment of your boat.


Hi Elessar,
thank you for your answer.
Does your company have experience with stern drive and sternthruster which is then installed not in the center under the hull but on the left or right side ? Or did I misunderstand Greg when he wrote about this technical possibility?

So it would be fixed under the hull but on the right or left side ????

The boat has a stair made from steel and wood outside of the stern ( in German it is called a " bathing- ladder " ) . It helps you to climb out of the water after taking a bath.

So there is no space to fix a construction directly at the stern. It must be fixed somehow under the water. The boat is made by glassfiber by the way.

And of course I will be exercise as much as I can !!!!!

But I want to be sure, that everybody who will be steering the boat will be able to get into any harbour and with any wind and current without risking a damage.

Kind regards from Germany,
Julia - Kristina

 

[duncan]

there is no obvious benefit to installing sternthrusters to your boat - the stern drive unit itself represents the only real fixed point you have so installing a system designed to push that one way or another is absolutely pointless (especially as it is already capable of vectored thrust itself).

the key is to understand the relationship between the available control from this and the influence the bowthruster can bring to bear on the bow - if anything you may find uprating the bowthruster might give you more confidence.

the real issue is practice - better still spend a day messing about in the marina with someone who really knows how to use the options you have already. There really are a lot.

however, you also need to understand how these become limited within the constraits of the wind conditions. Your boat has significant windage, but it's along the whole length of the boat.

To put all this in perspective it's a relatively simple exercise to get your boat to move sideways (either way but easier one way depending on the handing of your prop/outdrive), spin in it's own length (easier one way than the other) etc etc - you dont need more capability; you need to better understand what you have currently.

 

[Julia-Kristina]

Julia-Kristina to Duncan

Hi Duncan,
thank you for your mail.

I sometimes think I should better have bought a heavy boat with displacement hull and a deep keel...
This by the way was my first idea: fixing a keel under the hull.
But I was advised against this idea also and it would have been very expensive too because it is not a steel boat but made of fiber glass.

But on the other hand we like the shape of our Relcraft so much: spacious cockpit and a lot of space also on the roof of the cabin - our daughters spent quite a lot of hours on that roof this summer.

And it ist not so easy to find a similiar boat which is not a half glider ( that's the correct english expression ? ) with that space.

It's a pity that thy my idea with the sternthruster seems not to have been such a good idea.

But thank you again,
kind regards,

Julia-Kristina

 

[Monique]

A stern thruster will not be efficient in your case.

It is better for you to learn the dynamics of operating your boat, how it drifts, how to establish forward and rearward motion.

You should get a proper instructor and spend 1/2 a day in windy conditions. Once you understand the effect of wind on your boat, you will be at ease with the basic physics.

Good luck

 

[rubberduck]

http://www.side-power.com/public/templates/default.php?id=159&selected=2&selected2=159

I have the above installed on my stern drive boat & it works very very well.

 

[jfm]

JK, i agree the other comments:

1. you would be better just learning more on the boat. A stern drive IS a sternthruster, to some extent. It just needs a lot of practice
2. I would upgrade the bowthruster before adding a sternthruster. With a sterndrive and a bowthruster, and no stern thruster, you should be able to make the boat go sideways
3. But if you do decide to have a sternthruster, it does not need to be on the centreline. It can be mounted at the side (on the vertical face of the transom). You will need to avoid the bathing ladder, but that can be moved if necessary

Good luck

 

[Ripster]

I had a US sports boat, planing hull, about the same length and with a single Stern drive and BT. So I agree with most of the comments too. Your stern drive can be used (in conjunction with the BT) to make her go sideways. Yes in a wind and with some current/drift, its more tricky, but once you grasp how the dynamics come together (what control action makes the boat act in a certrain way) you will feel more at ease. Yes - definitely get some instruction and practice, practice, practice and then practice again! Plenty of fenders all round too in case you do come to rest where you did not intend!

 

[powerskipper]

Julia- Kristina

I would suggest you get some boat handling help, like a course to help you under stand how the boat works.

Astern thruster will not work greatly, when the boat is under way,[ moving though the water,] it is more for repositioning the stern when berthing or moving it over a bit, they tend not to be strong enough to push a boat very well against any kind of wind or tide.
If you fit a big one which mite work it will cause a lot of drag to your boat and will effect the handling greatly.

A boat course and some big ball fenders will help you more I think.

 

[MapisM]

Nothing to add to the previous technical suggestions, but...

The boat is laying on a lake (Lehnitzsee close to Oranienburg in the north of Berlin)
...
since we are living in the south of Germany, in Ingolstadt / Bavaria, but the boat is 5oo km away in the north of Berlin, I can not exercise every weekend.

...I suppose that the other posters either don't know these places or didn't notice this part of your post.
Forget thrusters, forget training, just keep your boat as it is.
Anyone willing to afford the above trip just to spend some weekends boating in Lehnitzsee has enough passion to learn each and every maneuvering trick in no time.
I bet that shortly after hitting the water next season you'll be able to teach to all of us...!

Oh, and welcome to the madhouse!

PS: don't worry if nobody welcomed you so far, around here it's up to us, non-UK boaters, to keep an acceptable standard of good manners. But most forumites are decent folks anyway!
Bye for now, must look for my coat...

 

[rafiki_]

Hi Julia-Kristina, Hi Greg

Sounds like your boat is a motor boat so you may get a better response from the Motor Boat Forum on this site. This forum is mostly used by people with sail boats. O.K. next time I will know.

I am not familiar with your make of boat but our first boat was a Princess 32, which had very flat sections on the rear part of the hull and as a consequence she tended to be affected by the merest puff of wind. Very nice boat, it was an alternative for us when we were looking for a boat to buy.

We had twin engines so it was a bit easier to manage than one engine will be. The thing is to practice - even with one outdrive you still have directional thrust that you can use to your advantage.
The general rule is steer before adding power in close quarter manoeuvring
do you mean steer and immediately afterwards add power ? and don't use too much power - if you can achieve what you need to by just slipping in and out of gear then that is best.
Find some space and play around with the engine and steering so you get a feel for how the boat responds. The boat is laying on a lake ( Lehnitzsee close to Oranienburg in the north of Berlin ), so there is enough space to exercise. But in some days the boat will be brought ashore by a crane so I have to wait with exercising until spring :-( In particular get a feel for the turning/pivot point on the boat - usually a point about two thirds of the length of the hull from the bow. It isn't like driving a car - when you turn the bow will go the way you want it to but the stern will also move in the opposite direction.

It is not unusual to have difficulties when first handling a boat thank you for your comfort and if you are a complete novice it is worth getting some training - you will be surprised what difference it makes to have someone show you the tricks of the trade.

With regard to the stern thruster I am not sure that it would be money well spent. As mentioned above, with a sterndrive you already have the ability to direct power where you need it. For example if you put the helm hard over to port and slip the engine into astern (reverse) the stern will move to port. The trick is to slip it in and out of gear so that you get the sideways movement without too much backward movement or the bow moving too much to starboard. You already have a bow thruster to help with the bow.

If you do decide that a stern thruster is needed I am not sure that two will be required. It might not be possible to mount it centrally because of the outdrive but assuming the transom is straight I can't see why one couldn't be mounted offset to the centre Interesting idea, I will ask at the shipyard if this would be technically possible
Personally I would go for learning to handle the boat rather than spending money.
The problem is that on the lake sometimes the wind appears suddenly and is quite strong.
And since we are living in the south of Germany, in Ingolstadt / Bavaria, but the boat is 5oo km away in the north of Berlin, I can not exercise every weekend.

I do not want to risk to damage other boats, so I want to be sure that I - and also our daughters, friends etc - can handle the boat under any wheather conditions. And that's why I had the idea with the stern thruster.
Of course I know that 90 % is exercising, and I will do that seriously, but I want to have a "security guarantee " for the last 10 %

Hope this helps.[

Dear Greg, thank you for your help ! Kind regards from Germany, Julia-Kristina

Julia-Kristina,

As other have said, with a bit of practice, you will find manouevering your boat will becomce easier. Just a quick question, why don't you move her to one of your beautiful Bavarian lakes? You will then be only an hour or so away, and will find it much easier to use her and clean/maintain her than up north in Prussia?

 

[Julia-Kristina]

JK to Rubberduck

http://www.side-power.com/public/templates/default.php?id=159&selected=2&selected2=159

I have the above installed on my stern drive boat & it works very very well.

Hi rubberduck,

I opened the link, thank you, but it seems this is an offer for twin sterndrive ??
Our boat has only 1 sterndrive.
But I also contacted already the company sidepower and they told me that wirth a single sterndrive you have to install 2 Sternthrusters .
Thanks again,
Julia-Kristina

 

[Julia-Kristina]

JK to jfm

JK, i agree the other comments:


3. But if you do decide to have a sternthruster, it does not need to be on the centreline. It can be mounted at the side (on the vertical face of the transom). You will need to avoid the bathing ladder, but that can be moved if necessary

Good luck

Hi jfm,
thank you for your advice. I will try to get some more technical informations about that idea in our shipyard.
You are also in Antibes ? I spent about 1 year in Nice and Antibes, but hundred years ago...But I know the harbour of Antibes quite well. I was there some weeks ago, still a very nice place with a lot of beautiful boats.
Kind regards JK

 

[Julia-Kristina]

JK to ripster

...Plenty of fenders all round too in case you do come to rest where you did not intend!

Hi ripster,
I got 8 fenders on the boat when I use it, and one fenderball at the front...The ship ist enwraped like a baby . Everybody notices from two miles distance that I am a beginner
And I will practise, of course !

Kind regrads from JK

 

[Julia-Kristina]

JK to powerskipper

Julia- Kristina


Astern thruster will not work greatly, when the boat is under way,[ moving though the water,] it is more for repositioning the stern when berthing or moving it over a bit, they tend not to be strong enough to push a boat very well against any kind of wind or tide.
If you fit a big one which mite work it will cause a lot of drag to your boat and will effect the handling greatly.

A boat course and some big ball fenders will help you more I think.

Hi powerskipper,
I don't have problems when the boat is under way, she then goes very easy - the problems occur when I have to go very slowly and cautious in a harbour.Then the effect of the sterndrive is very little and obviously not able anymore to move the stern.
Thank you for mentionning the eventual problems concerning drag.

She got 8 long big fenders and 1 ballfender at the bow !!
Thank you,
kind regards,
JK

 

[Julia-Kristina]

Germany to Italy

...I suppose that the other posters either don't know these places or didn't notice this part of your post.
Forget thrusters, forget training, just keep your boat as it is.
Anyone willing to afford the above trip just to spend some weekends boating in Lehnitzsee has enough passion to learn each and every maneuvering trick in no time.
I bet that shortly after hitting the water next season you'll be able to teach to all of us...!

Oh, and welcome to the madhouse!

PS: don't worry if nobody welcomed you so far, around here it's up to us, non-UK boaters, to keep an acceptable standard of good manners. But most forumites are decent folks anyway!
Bye for now, must look for my coat...

Hi MapisM,

may I hug you for this warm welcome ?

And thank you for the trust you seem to have in my abilities...
But I think the advices I got until now are quite reasonnable : I am sure - I do need a lot of training !

E italiano ?
Da dove viene ? E dove hai la tua barca, cioè in que porto in Italia ?

Grazie ancora per la tua lettera molto gentile,

ciao,
Julia- Kristina

 

[Julia-Kristina]

Bavaria or Berlin

Julia-Kristina,


Just a quick question, why don't you move her to one of your beautiful Bavarian lakes? You will then be only an hour or so away, and will find it much easier to use her and clean/maintain her than up north in Prussia?

Hi Rafiki,

the lakes in Bavaria are beautyful, I think that too, but they are more convenient for sailing than for using a motorboat.
( Our daughters do sailing and they like to go there because the winds are very favourable most of the time and it's just a very nice region. )
But with a motorboat you are turning around the lake and that's it.

After one month you now every wave by name.

But from Berlin up to the coast of the baltic sea you have a marvellous region for motorboats with more than 2000 ( ! ) lakes and rivers and channels which are left in their natural state - and they are all connected.

Ideal for motorboats.
With a canoe you even have 40.000km ( approx 25.000. miles ) available. With a boat it's less of course because of the draft.

The biggest lake is the " Lake Müritz " with approx. 117 squarekilometers.
You have small channels with waterlilies, you see ducks and swans and muskrats, sometimes you have the impression to be in a primeval forest.
Just wonderful.

And in the little marina where she is laying there is somebody who looks after her, cleans her etc.

So you see now why I accept to go 500 km to join the boat...

I wish you a nice day,
JK