Chris H
Well-Known Member
How many seals have you had to replace ?
40-50 foot sport cruisers with surface drives?
- Thread starter lufihengr
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PowerYachtBlog
Well-Known Member
As far as as maintenance goes, I had a client who had a Fairline Targa 38 with DPHs and Volvo D6 370hp, and then had a Pershing 52 with Man 1050s.
As far as maintenance goes in between the two drives and after three years of owning both he said what he spent on the Arnies was relatively cheaper to what he spent on the DPH in the same time frame.
Say 50% of the cost. Also keep in mind here that Fairline was a two year old boat when he bought it, while the Pershing was fourteen years old.
As far as maintenance goes in between the two drives and after three years of owning both he said what he spent on the Arnies was relatively cheaper to what he spent on the DPH in the same time frame.
Say 50% of the cost. Also keep in mind here that Fairline was a two year old boat when he bought it, while the Pershing was fourteen years old.
jointventureII
Well-Known Member
In the 2 years I've been working on this boat, none. We're doing all of them in March.
Chris H
Well-Known Member
Reason I asked was I’ve been told to treat the arnesons like a car diff, change the oil every so often then leave them alone until something happens.........seems like another myth !
jointventureII
Well-Known Member
Service manual gives a massive interval for oil change (1000 hours IIRC?). To be honest the problem we have is the central engine (triple engine setup) sits very low so there is a control system to close off all the valves, to stop syphoning. This is great when it works...
Came back from Tunisia in September and the control system died, taking the central engine with it as the system initiates emergency shutdown! Too lumpy to risk restarting as well
Portofino
Well-Known Member
You will be following my mate and flushing out the hydraulic fluid every year + new ram seals while it’s out on the hard for it’s annual = piece of mind , no show stoppers in the summer .
Chris H
Well-Known Member
If the rams are clean there is no point changing the seals annually, if the rams get some stubborn growth on them, it will knacker new or old seals, I doubt the seals themselves wear very much doing their normal job.
Chris H
Well-Known Member
Have you looked into putting an air pipe to the props ?
Portofino
Well-Known Member
That’s correct .
Its just a big “If “ with a boats left parked up between use and no permanent crew to look after .
It’s winter and seeing as we are doing Surface drives .....
The external ram in the Med thing has been engineered out .It’s a recognised issue .
Here is one example , the factory is Cannes la Bocca I have been a few times as they are a an anode + gen sterngear wholesaler with a retail
The rams are inside the transom always dry .A lot of commercial like Gardia Finanza use SDS .....needs to be turn key .
https://www.surfacedrivesystem.fr/
“Reliability & Efficiency
With our SURFACE DRIVE SYSTEM, all vital components are protected from salt and water corrosion as all cables, sensors, hydraulics, hoses, and electric connections are inside the engine room.
Every part of the SDS is thought and conceived to be heavy duty and has a rigourous quality control at each production step.
High strength material such as NiBrAl is used for boat propulsion endurance and performance. Please consult our manufacturingprocesses.”
Rams inside .
Another is Trimax , it has a rudder with rams out of the water like a conventional steering system .Some adjust the initial drag because of the extreme prop pitch by airating the props to lower the water density .So do without any under water pitch rams because the prop shaft angle is fixed .As it’s not necessary to raise 1/2 the prop out to ease the load on the engine at low revs while it’s accelerating like Anrnesons
A cat skinning excerise
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Elessar
Well-Known Member
you need the speed to go back and get the guests you left behind. How could they make a 60ft boat so small?With speed to work you need the right hull form .Deadrise and weight distribution come into play .
Plus as I said 3 up front looking out and breezy for hair do‘s .No hats ever last
jointventureII
Well-Known Member
Yeah indeed. We just let the Twin Disc guys decide what needs doing. Not let us down so far.
No I've not to be honest although I've seen a few with them installed. The problem is the central riser elevation, it's literally 45cm above the waterline....! Not a lot in any boat let alone a 108 fter
Chris H
Well-Known Member
Do you look after La Cima, with the big engines ?
jointventureII
Well-Known Member
No (La Cima is a 115 I think?), I'm on a Pershing 108 so very similar!
Chris H
Well-Known Member
Your right, it was the owner that got me looking at Pershing.
MapisM
Well-Known Member
On Arnies powered boats? Good luck.
Below is the system that Buzzi designed for venting his Trimax surface transmissions.
Which are for NOT trimmable, but he did design for them a peculiar central trim tab, to which the venting hoses are connected and can therefore be lowered/raised.
Now, leaving aside the trim tab, the drawing can be used to think how a venting system should be designed to follow the movements of a trimmable transmission.
And before even considering the technical complications, I don't think any Pershing owner would want to drill big holes in the swim platform, stick hoses through them, and connect them to large scoops above the transom!
But if you are aware of any easier and still effective solution, I for one would be curious to hear about it.
Chris H
Well-Known Member
There is a magnum moored a few spots from me that has been modified with two tubes to the drives, they terminate just below the swim platform, the owner says it gives better top speed but more importantly it gets on the plane quicker.On Arnies powered boats? Good luck.
Below is the system that Buzzi designed for venting his Trimax surface transmissions.
Which are for NOT trimmable, but he did design for them a peculiar central trim tab, to which the venting hoses are connected and can therefore be lowered/raised.
Now, leaving aside the trim tab, the drawing can be used to think how a venting system should be designed to follow the movements of a trimmable transmission.
And before even considering the technical complications, I don't think any Pershing owner would want to drill big holes in the swim platform, stick hoses through them, and connect them to large scoops above the transom!
But if you are aware of any easier and still effective solution, I for one would be curious to hear about it.
Chris H
Well-Known Member
Portofino
Well-Known Member
^^^ Aeration , actually exhaust gas * as I said reduces the density of the water so the props spin up faster your acceleration point .As far as increase in speed because of the less dense medium he can dip the props deeper , or less out of the water thus more thrust . But he has to careful not to overload the motors , you know EGT s and all that
A lot depends on the Dia of the props .He May have changed his props ? Running with more pitch , bight and thus speed for a given rpm ,Assuming he hasn’t altered the G box ratios ? The new gas means he can safely use a bigger pitch maybe ?
Either way it sounds like a possibility of the engines shortening life rabbit hole to fall into .
The picture I posted above of the trimax have smaller diameter over Arnesons and greater pitch Rolla stainless steel props .
S Steel is less flexible more stiffer than the Arneson nibral s .It can receive the forces better without distorting.
A lot of trimax due to the fixed pitch have two speed gearboxes to ease the load on the engines in “first “ .getting up on the plane .How ever once up after the turbos spool = more gas they change up into “top “.
* it’s not necessarily all the exhaust gas , just a proportion diverted off , so more expense or trial + error finding the correct Y piece , the dia of pipe for the aeration .This may have knock on effects to turbo boost pressure in the system ?
A lot depends on the Dia of the props .He May have changed his props ? Running with more pitch , bight and thus speed for a given rpm ,Assuming he hasn’t altered the G box ratios ? The new gas means he can safely use a bigger pitch maybe ?
Either way it sounds like a possibility of the engines shortening life rabbit hole to fall into .
The picture I posted above of the trimax have smaller diameter over Arnesons and greater pitch Rolla stainless steel props .
S Steel is less flexible more stiffer than the Arneson nibral s .It can receive the forces better without distorting.
A lot of trimax due to the fixed pitch have two speed gearboxes to ease the load on the engines in “first “ .getting up on the plane .How ever once up after the turbos spool = more gas they change up into “top “.
* it’s not necessarily all the exhaust gas , just a proportion diverted off , so more expense or trial + error finding the correct Y piece , the dia of pipe for the aeration .This may have knock on effects to turbo boost pressure in the system ?
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Portofino
Well-Known Member
Here we have a Otam 80 with quad MTU 10 V 1640 hp s .Running on trimax x4
Just to illustrate the exhaust complexity .It’s got the lot .
Two huge underwater to reduce boom at the lateral aspects , see the black holes .
Four “ fart pipes “ just above the water line .
Then the rectangular aeration pipes , you can just see the outer pair in the shot between the prop blades .
Additionally obviously not illustrated is the very poor turning circle at speed as the rudders for lower drag as woefully small .
So to meter out the 45 knot cruise ( 54 wot on a clean bottom ) they have to go far out away from traffic or slow it down to make avoiding manoeuvres .A right PITA ,
Thats where Arnesons are advantageous as you can steer them at speed easily with the confidence of navigation through the “Piccadilly circus “ in the SoF .
Just to illustrate the exhaust complexity .It’s got the lot .
Two huge underwater to reduce boom at the lateral aspects , see the black holes .
Four “ fart pipes “ just above the water line .
Then the rectangular aeration pipes , you can just see the outer pair in the shot between the prop blades .
Additionally obviously not illustrated is the very poor turning circle at speed as the rudders for lower drag as woefully small .
So to meter out the 45 knot cruise ( 54 wot on a clean bottom ) they have to go far out away from traffic or slow it down to make avoiding manoeuvres .A right PITA ,
Thats where Arnesons are advantageous as you can steer them at speed easily with the confidence of navigation through the “Piccadilly circus “ in the SoF .
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Chris H
Well-Known Member
The pipes I’ve shown go to fresh air, air is pulled through the pipes, there is no exhaust or air scoop.^^^ Aeration , actually exhaust gas * as I said reduces the density of the water so the props spin up faster your acceleration point .As far as increase in speed because of the less dense medium he can dip the props deeper , or less out of the water thus more thrust . But he has to careful not to overload the motors , you know EGT s and all that
A lot depends on the Dia of the props .He May have changed his props ? Running with more pitch , bight and thus speed for a given rpm ,Assuming he hasn’t altered the G box ratios ? The new gas means he can safely use a bigger pitch maybe ?
Either way it sounds like a possibility of the engines shortening life rabbit hole to fall into .
The picture I posted above of the trimax have smaller diameter over Arnesons and greater pitch Rolla stainless steel props .
S Steel is less flexible more stiffer than the Arneson nibral s .It can receive the forces better without distorting.
A lot of trimax due to the fixed pitch have two speed gearboxes to ease the load on the engines in “first “ .getting up on the plane .How ever once up after the turbos spool = more gas they change up into “top “.
* it’s not necessarily all the exhaust gas , just a proportion diverted off , so more expense or trial + error finding the correct Y piece , the dia of pipe for the aeration .This may have knock on effects to turbo boost pressure in the system ?