Info needed on HP for several vehicles please

[Kevan Dalby]

Hi all

Does anyone know the approxiimate HP of the following rovs?

Seaeye Surveyor Plus
Seaeye Panther XT
Seaeye Panther XT Plus

Sub Atlantic Super Mohawk
Sub atlantic Comanche

SMD Atom

I have enquiries in with the manufactrers but no responses as yet and with the weekend involved it is also not helping.

Any feed back appreciated.

** Is there any way / formula for converting bollard pull etc to HP equivalent? ***

thanks

[Donald Faulds]

Subseauk

Bollard pull depends on the thrusters fitted. It is just a measure of force and does not tell you how fast the ROV can fly.

Horsepower refers to the power delivered by the output shaft of the primary subsea electric motor of a hydraulic powered ROV. There is not a direct equivalance with electric thruster ROVs.

The only reasonable way of measuring one ROV against another, in flying terms is the calculated maximum speed in knots – as this combines force and drag area. Note that power required is proportional to the square of the speed. Eg: A 3.5 knot ROV uses twice the power of a 2.5 knot ROV.

I hope that gives you a few clues……..

[Kevan Dalby]

Subseauk

Bollard pull depends on the thrusters fitted. It is just a measure of force and does not tell you how fast the ROV can fly.

Horsepower refers to the power delivered by the output shaft of the primary subsea electric motor of a hydraulic powered ROV. There is not a direct equivalance with electric thruster ROVs.

The only reasonable way of measuring one ROV against another, in flying terms is the calculated maximum speed in knots – as this combines force and drag area. Note that power required is proportional to the square of the speed. Eg: A 3.5 knot ROV uses twice the power of a 2.5 knot ROV.

I hope that gives you a few clues……..

Hi DonF

I’m not after the speed they can do and kgf / bollard pull has always been a subjective measurement in my opinion with a lot a variables ie initial pull force where props have water to dig in against continuous pull where there would be cavitation etc also speed and kgf subject to tether out etc.

What i was asking was due to a request from my boss who can only get his head around HP as an indication of power ( i know again subjective really ) but what can i say if HP is what he’s after then HP i have to find!!!

thanks for the input.

[Des_b]

Hi Subseauk,

1 HP is 746watts so if you can work out or know the power of your prospective vehicle, you can use normal electrical formula to work it out.
Finding HP for DC, AC single Phase and AC 3 phase:
DC:
V x I x eff/ 746

AC single phase:
V X I X eff x PF/ 746

AC 3 phase:
V X I X PF X 1.736/ 746

where PF (power factor) is watts/Volt-amps
and eff (efficiency) is output/input

Unfortunately I dont have any info to hand on the vehicles you listed, but I hope this helps…..

[Des_b]

Hi Subseauk,

1 HP is 746watts so if you can work out or know the power of your prospective vehicle, you can use normal electrical formula to work it out.
Finding HP for DC, AC single Phase and AC 3 phase:
DC:
V x I x eff/ 746

AC single phase:
V X I X eff x PF/ 746

AC 3 phase:
V X I X eff x PF X 1.732/ 746

where PF (power factor) is watts/Volt-amps
and eff (efficiency) is output/input

Unfortunately I dont have any info to hand on the vehicles you listed, but I hope this helps…..

Sorry, biffed out as the internet is super slow!!!!!!

[Kevan Dalby]

Cheers Des

I’m in the same boat trying to get the power ratings etc for some of the systems. Being a weekend don’t help.

thanks for the input.

[Andy Shiers]

Also ….. power to weight ratio can be put into an equation.
A larger vehicle does not necessarily mean it can cope with a cross current ! A compact vehicle will have the same effect as wind blowing against a wall where as a vehicle which is open with plenty of space for the water to flow through has a greater chance of staying on the pipeline.
Both Scorpio and Sparten had troubles coping with cross currents off Qatar. Bog standard Panther did it in the end 😯
Sparten also had troubles coping with the temperature out there 😕

[Donald Faulds]

KW and HP will only tell you how fast the electrons are passing down the umbilical. The same electrical (or hydraulic) power to different sizes of thrusters will give different force out (ie bollard pull).

For example: SubAtlantic SA300 give 320kgf for 20kw hydraulic. SA500 give 500kgf for 20kw hydraulic. Okay, that is a bit extreme but it matters lot whether you use 12" or 15" and the prop type etc. Same sitaution with electric thrusters.

All these factors, and more, get taken into account in a speed calculation.

A 100hp Spartan only has 12" thrusters and can’t cut it against an old time MRV with 15", for example, even though the MRV was a bit bigger frame.

(Anyhow, if your boss doesn’t understand then he doesn’t understand!)

[Kevan Dalby]

Too True mate

🙄

[Andy Shiers]

That’s why he’s a boss 😆

[Lloyd Todd]

ROV Comparison Table why dont you look on there web sites?

http://www.sub-atlantic.co.uk

Model Navajo Mohawk Mohican Super Mohawk Comanche
Power 4.4 kW
6 hp 7 kW
9 hp 13 kW
17 hp 13 kW
17 hp 35 kW
47 hp

[Kevan Dalby]

Thanks MD

i had done this but several not listed as HP but conversions now done and i meant to post this as no longer required.

Appreciate the info though

Rgds

[Author]

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