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Old 08 January 2011, 05:13   #71
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Although I have no experience of your actual hull I am a racer and boat builder.

A counter rotation Fleetmaster should have been very cheap - as others have said it makes it very difficult to set up as the prop choice is very small indeed. I would have recommended a Sportmaster not a Fleetmaster for this application.

A Tempest prop is usually a very stable prop - see if you can get a Laser of the next pitch up and try that.

The chine walking especially on slowing down I would suggest is as much prop as anything and until you are not hitting the rev limiter I wouldn't change anything else. Chine walking is also a feature of high performance boats - different props can help but it is always a combination of factors.

With high performance engine mounted higher on the transom we mount motors in the centre - Ospreys may be different.

Is the steering hard to turn with the trim all the way in - try trimming the motor out a little and it should improve.

You need to work out the slip for the different setups, record the speed (at least two directions to remove tide and wind), RPM and enter the results with the gear ration here: Prop Calculator

Bubbles in the steering will not make the steering heavy but will not help with the chine walking.

The difference in the amount of heel from left to right turns is due to the offset of the motor and the direction of the prop - it is reversed for right hand rotation motors.

A 25" motor set up for speed is always going to end up high on the transom and will definitely not help with the chine walking - I would always recommend 20" maximum with a R/H Sportmaster, with the motor you have it will always be a compromise and never ideal.

I hope the above is some use to you and is just my opinion.
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Originally Posted by Zippy
When a boat looks that good who needs tubes!!!
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Old 08 January 2011, 07:40   #72
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Originally Posted by Cookee View Post
Although I have no experience of your actual hull I am a racer and boat builder.

A counter rotation Fleetmaster should have been very cheap - as others have said it makes it very difficult to set up as the prop choice is very small indeed. I would have recommended a Sportmaster not a Fleetmaster for this application.

A Tempest prop is usually a very stable prop - see if you can get a Laser of the next pitch up and try that.

The chine walking especially on slowing down I would suggest is as much prop as anything and until you are not hitting the rev limiter I wouldn't change anything else. Chine walking is also a feature of high performance boats - different props can help but it is always a combination of factors.

With high performance engine mounted higher on the transom we mount motors in the centre - Ospreys may be different.

Is the steering hard to turn with the trim all the way in - try trimming the motor out a little and it should improve.

You need to work out the slip for the different setups, record the speed (at least two directions to remove tide and wind), RPM and enter the results with the gear ration here: Prop Calculator

Bubbles in the steering will not make the steering heavy but will not help with the chine walking.

The difference in the amount of heel from left to right turns is due to the offset of the motor and the direction of the prop - it is reversed for right hand rotation motors.

A 25" motor set up for speed is always going to end up high on the transom and will definitely not help with the chine walking - I would always recommend 20" maximum with a R/H Sportmaster, with the motor you have it will always be a compromise and never ideal.

I hope the above is some use to you and is just my opinion.
Thanks for your advices.

The thing as you probably do not know all the mercury XS engine have been banned from the classic french boating market. Indeed they are now restricted to the racing market which makes them really difficult to find.
Anyway my engine was the last one in new condition on the french market. Then I did not have any choice with the rotation direction and the shaft.
So I did not choose it to save money but to get a new 300xs.
I may have make a mistake.....but now I can't go back.

I am looking for a tempest plus 25 or 26 LH. Does anyone knows if it exists ?
I have also heard about torque tab which can be put on the skeg. I know the sportmaster has been build with this tab already. But an extra market torque tab would certainly much cheaper than a sportmaster shaft (6000euros at least...). Does anyone know about it ?

The last solution I have is to reduce the length of shaft from 25' to 20' for around 1500euros but would it stop the steering pb so far ? I am not sure.

Regards.
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Old 08 January 2011, 08:45   #73
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But an extra market torque tab would certainly much cheaper than a sportmaster shaft (6000euros at least...). Does anyone know about it ?
1. Here
2. Here LH and 3500euros
3. Here says he will split
4. Here Cheap - 1,400

Some might be out of date but a good indication of price

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Originally Posted by Vipermax View Post
The last solution I have is to reduce the length of shaft from 25' to 20' for around 1500euros but would it stop the steering pb so far ? I am not sure.
How would this help? Surely this would raise the engine even more resulting in more cavitation, more slip, less speed etc etc.
Best thing to do is lower the engine a notch on the jack (which you said was possible). If this does not help then try without the jack like DHD said, most of us run 25" legs with the transom built for XL shaft, and if you did the same then there would be nothing to go wrong.
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Originally Posted by Vipermax View Post
I am looking for a tempest plus 25 or 26 LH. Does anyone knows if it exists ?
I have also heard about torque tab which can be put on the skeg. I know the sportmaster has been build with this tab already. But an extra market torque tab would certainly much cheaper than a sportmaster shaft (6000euros at least...). Does anyone know about it ?
According to their site the Tempest Plus is only available in "select" sizes for LH, but maybe you could have it reworked if necessary. Using the data you gave (see pic) the merc prop calculator reckons you should go for a Bravo 1 24", a rev4 23" or a tempest 24" or 25" however you have already tried most of these. I think you should definitly lower the motor before playing with props though. This is a pic of my transom, the engine is not at lowest tilt but you get the idea, if we wanted high speed we could probably change prop to a raker 23" and have it reworked down 1/2" and then raise a bit but we are happy with 52knts; all round is good with great acceleration and grip as long as you trim in a little bit (not loads just a little). We also have trim tabs so can keep bow down with the engine up

It is quite a bit lower than yours I think, you can see where the L2 box joins to where the shaft was conceived for the Magnum, much the same as yours.

ATB, Oliver
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Old 08 January 2011, 13:34   #74
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No, the motor shouldn't be included in the measurement.

I measured it along the centreline using plumblines dropped from the front of the bow fender and from a straightedge across the rearmost part of the toob end cones.

I'll have another go at it tomorrow, to see if it's grown.
Just re-measured: 5.84m
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Old 08 January 2011, 13:41   #75
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Twas cold out there.
You're not including the trailer now, are you?
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Old 09 January 2011, 12:37   #76
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Quote:
Originally Posted by Vipermax View Post
Thanks for your advices.

I am looking for a tempest plus 25 or 26 LH. Does anyone knows if it exists ?
I have also heard about torque tab which can be put on the skeg. I know the sportmaster has been build with this tab already. But an extra market torque tab would certainly much cheaper than a sportmaster shaft (6000euros at least...). Does anyone know about it ?

The last solution I have is to reduce the length of shaft from 25' to 20' for around 1500euros but would it stop the steering pb so far ? I am not sure.

Regards.
Not sure about the props - call Steel Developments and they will give you a price and availability +44 2088 747059

It would have to be a right hand box to have a tab on it, they grind them off on the left hand boxes as it's on the wrong side!

If you cut the transom down it will solve all of the problems regarding the hydraulic hoses and if you want to fit a 20' just take 5 or more inches off the transom - any competent boatyard will be able to do it for you and reseal the transom to prevent the water getting at it.

Try the props first and see where that makes any difference.
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Originally Posted by Zippy
When a boat looks that good who needs tubes!!!
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Old 09 January 2011, 12:40   #77
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Originally Posted by gotchiguy View Post
Well to be technical... to turn the 150 into the 150HO is just a map. The 200 to 200HO is a completely different engine, the 200 is 60deg small block and the 200ho is big block 90deg. The 200ho produces 217hp but it is not a racing engine, rather a version of the 200 designed for heavier boats. The 225ho is just a map and a different gearcase, currently the L2 which has low water pickups for those who run them ridiculously high on bass boats, and the 250ho is a 300hp with the racing L2 gearcase and a slight detune. The certification for outboards means they can be +/- 20% of rated hp, and the 250ho is generally regarded as having over 270hp at the prop shaft. Bear in mind however that all HOs are designed for the Yank bass boats and the gearcases are not designed for offshore boats like ours. This is the same for all the Mercury XSs and ProXS, but the Evinrude gearcases are regarded as their weakest point in the racing scene compared to the mercs, some have even bolted on an OMC V8 gearcase to compensate.
I would go and check your information on the above - not sure where you got all of that from but as far as I know it's all a bit different to that.
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Old 09 January 2011, 13:08   #78
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Originally Posted by Cookee View Post
Not sure about the props - call Steel Developments and they will give you a price and availability +44 2088 747059

It would have to be a right hand box to have a tab on it, they grind them off on the left hand boxes as it's on the wrong side!

If you cut the transom down it will solve all of the problems regarding the hydraulic hoses and if you want to fit a 20' just take 5 or more inches off the transom - any competent boatyard will be able to do it for you and reseal the transom to prevent the water getting at it.

Try the props first and see where that makes any difference.
Thanks for the advices Cookee.

I have just been through your website and I wonder how fast your boat is going and what is and how powerful is your engine.

Thanks.

Jc.
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Old 09 January 2011, 13:12   #79
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Thanks for the advices Cookee.

I have just been through your website and I wonder how fast your boat is going and what is and how powerful is your engine.

Thanks.

Jc.
The RIB did 91.5mph at Coniston with an EFI 280 ROS - it had a Sportmaster gearbox and a Raker on for that attempt - we usually race with a thinned Tempest prop.

The new boat will have twin Yanmar BY260 diesels with Arneson drives and we are hoping for 70mph approx.
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When a boat looks that good who needs tubes!!!
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Old 09 January 2011, 13:17   #80
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The RIB did 91.5mph at Coniston with an EFI 280 ROS - it had a Sportmaster gearbox and a Raker on for that attempt - we usually race with a thinned Tempest prop.

The new boat will have twin Yanmar BY260 diesels with Arneson drives and we are hoping for 70mph approx.
That is huge ! Anyway it is a very nice boat and obviously a nice work !

Hope your future boat will match your expectations !
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