VOLVO PENTA - MED design for success IPS related.pdf

Design for success

Mediterranean Trip 2014

Volvo Penta

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IPS Inboard Performance System

IPS 1 IPS 2 IPS 3


Volvo Penta

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The name indicates the equivalent inboard shaft installed power at about 30-40 knots

Engine Pod Product D4-260 IPS1 IPS350 D4-300 IPS1 IPS400 D6-300* IPS1 IPS400MC D6-330* IPS1 IPS450 D6-370 IPS1 IPS500 D6-435 IPS1 IPS600

Engine Pod Product D11-510** IPS2 IPS650 D11-625* IPS2 IPS800 D11-725 IPS2 IPS950

Engine Pod Product D13-700*** IPS3 IPS900 D13-800* IPS3 IPS1050 D13-900 IPS3 IPS1200

*** - Engine and POD rating 3 (commercial planing and semiplaning craft) ** - Engine rating 3, POD rating 4 (commercial planing and semiplaning craft) * - Engine and POD rating 4 (commercial planing and semiplaning craft)

IPS nomenclature


Volvo Penta

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Why do we get involved?

Volvo Penta has introduced a state of the art propulsion system that is fundamentally different from traditional configurations which means that the market lacks experience.

Volvo Penta has been involved in many development projects at key OEMs and has tested a large number of boats.

Volvo Penta can help take some of the guess work out of the seemingly simple equation.

No propulsion system is better than the vessel it is fitted to.

+ = ?


Volvo Penta

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Potential

0.50

0.55

0.60

0.65

0.70

0.75

25 30 35 40 45

Boat Speed [knots]

EtaN

et

The potential advantage for IPS can only be fully realized if the hull design and load cases are well matched to the propulsion

IPS

Traditional Fixed Pitch Prop


Volvo Penta

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Planing/semiplaning hull shapes and speed potential

Volvo Penta can NOT deliver outside this range. Speed is indicating nominal max rpm on the engine

Design speed

IPS900 IPS1050 IPS1200 (D13-700, 1.99) (D13-800, 1.88) (D13-900, 1.88)

QS5 21 kn N/A N/A Q1 23 kn 26 kn N/A

Q2 to Q7 25-37 kn 28-41 kn 27-40 kn

Design speed

IPS650 IPS800 IPS950 (D11-510, 1.70) (D11-625, 1.70) (D11-725, 1.70)

PS4 to P1 21-24 kn 22-25 kn N/A P2 to P7 25-37 kn 27-40 kn 27-41 kn

Design speed

IPS350 IPS400 IPS400MC IPS450 IPS500 IPS600

(D4-260, 2.08) (D4-300, 2.08) (D6-310, 1.94) (D6-330, 1.94) (D6-370, 1.94) (D6-435,

1.82) TS3-TS6 18 - 23 kn 19 - 26 kn 19 - 26 kn 19 - 25 kn 17 - 24 kn 19 - 26 kn T2 to T10 25 - 44 kn 28 -48 kn 28 - 47 kn 27 - 47 kn 26 - 45 kn 28 - 49 kn Red = preliminary

Only for low speed


Volvo Penta

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New General Arrangement for suitable LCG

High drag

Low drag

Horizontal thrust

Bow up

Bow down

Horizontal thrust angle + Low appendage drag + LCG further aft = Higher trim which can mean higher drag A change in trim can be compensated for with suitable GA (engines, tanks, equipment, driver position, etc.)


Volvo Penta

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Deadrise distribution for higher speed hulls

The hull is monohedron if buttocks are parallel The hull is warped if buttocks converge Sketches are exaggerated for illustration purposes

IPS is most common in planing type hull shapes: Hull drag is affected by the distribution of deadrise. A large change in deadrise over the lifting

surface increases drag in comparison to a straighter running surface for fully planing hulls. However, given a specific load case, warp can be used to aid the running attitude for best

performance. Highest efficiency so far has been achieved with monohedron hulls.

Monohedron

Warped


Volvo Penta

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Deadrise distribution for lower speed hulls

The traditional rising buttock hull has been judged and in to be well suited towards IPS given the right relative speed, geometry and load balance. However the IPS units have so far (tested examples) been fitted on close to a horizontal line which will help both in thrust direction but also give some added dynamic pressure/lift.

Preferred

Sketches are exaggerated for illustration purposes


Volvo Penta

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Roll factor During the time the IPS system has been on the market, Volvo Penta has gathered a large amount of experience around hull design and boat behavior. Due to some geometrical aspects of the propulsion system boats equipped with IPS tend to heel more than boats with conventional inboard systems, this is true both when turning as well as when running straight with side wind. An experience database has been developed where the proneness to heel is estimated. The indicator is a property Volvo Penta calls Roll Factor and the range is approximately from 2 to 5 where a high number indicates more stability than a lower number. Because of this experience it is possible to find a range of Roll Factors where warnings are issued and if the number becomes too extreme the recommendation has to be that VP declines to fit the IPS system altogether. A number below 2.60 will generate a warning and a number below 2.20 should be avoided without radical geometrical modifications.

Volvo Penta has developed a method to judge the proneness to roll in turns by means of an empirical formula. The basis for this formula is tests run with a number of boats measuring the behavior.

Input for this formula is: Bp, , VCG, Lwl and the geometry of the chine area.

Applies to boats up to abt. 50 ft but is being developed for larger boats (pending statistical material)


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Chine design for less heel

Chine width: Standard hull: 5% of chine beam High Vcg: minimum 5% of chine beam Allow proportional width to at least Lwl/2 Chine design: Standard hull: neg 5 High Vcg: minimum neg 5


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Moderate bottom loading and window of operation

Avoid loading the bottom too hard. A highly loaded bottom limits the window of operation.

LCG should be placed so that the bow can be lifted when running in following seas.

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VOLVO PENTA - MED design for success IPS related.pdf

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