[PSUBS-MAILIST] Thruster Horse Power

[Alan via Personal_Submersibles]

Thanks Vance,
I'm working through the brushless thruster options.
7 out of 8 thruster manufacturers I've looked at use brushless motors.
At least 1/2 either have, or give you the option of oil compensation.
This could be for cooling as much as for deeper depth operation.
I am working on 750 Watts = 1 hp. The bollard thrust figures seem to
vary quite a bit in relation to the Watt ratings of the different motors / manufacturers.
Nuytco has the best bollard thrust per watt at 70 lb. thrust for the 750W model
but as the Watts go up, the thrust goes down ie 1,500W model has 110 lb. which
is only slightly better than the Minn kotta 101.
All a bit confusing.
Alan



Sent from my iPad

> On 19/09/2014, at 7:27 am, Vance Bradley via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Alan,
> Loosely speaking that would be about correct. Limited to older prop designs perhaps. Back in the day, Perry ran a 7.5 hp motor in pc-5, PC-8 and ps-2, all of which ran to 6-tons(ish) in launch trim. The PC-9 weighed 12-tons or better and started life with the same drive package. It wasn't enough so when we retro-fitted her we went with (I think) 15, which was overkill. Then Intersub opted for what became the PC-1201 and her sisters. Based on the experience with emthe others and the PC-15 (which had two 10 hp units chained and clutched together driving through a reduction gear) they settled in for the standard which was 10hp. All of them drove big props through reduction gears and that drive complete weighed about 900 pounds and produced nearly that much of a bollard pull. The 18s used a different motor with no reduction gear but were also 10 hp. Phil Nuytten talks horsepower rather than pounds of thrust. The Newt-screws are variable depending on input voltage, as I understand !
> it. Running 5-hp at 240 volts for instance means you could use two of those to replace the big Perry unit and save about 700 pounds of payload with roughly the same thrust output.
> Vance
> Sent from my iPhone
> 
>> On Sep 18, 2014, at 7:57 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> I'm sending this again.
>> Apologies if it came through previously, but yahoo is telling me 
>> it has "no content" & no one replied.
>> Mainly for Vance,
>> Vance I think off the top of your head you came up with a figure of  about 1 hp of
>> combined horizontal thrust for every ton of submarine, as a ballpark figure for
>> a lot of the subs you are familiar with. Is that correct or can anyone else remember that?
>> Also what was the Deep Workers new thruster rating thanks.
>> Alan
>> 
>> 
>> Sent from my iPad
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