Double screws

alant · 30 Dec 2003

How much benefit do these give you guys on powerboats?

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seafarer · 30 Dec 2003

Manoeuvrability at close quarters. IMHO

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hlb · 30 Dec 2003

Do you mean Twin screws or duo props??

<hr width=100% size=1> No one can force me to come here. I'm a volunteer!!.

Haydn

Talon · 30 Dec 2003

You can turn on the spot.

I only use the engines to steer the boat when I moor up, no steering required.

Centre up the steering, use the throttles in 2 - 4 second clicks and wait for the boat to move where you want it to go. Really easy.

But if the weather blows up, then you need to use steering and throttles, that can become a bit of a head f***, where is the rudder position, do I want forward on the stbd or reverse on the port engine. It can be a handfull. /forums/images/icons/frown.gif

<hr width=100% size=1>Alex

Renegade_Master · 30 Dec 2003

Alex for goodness sake get rid of that awfull creepy thingy and put a pick of yer boat on................. Back to the subject, agree with Alex comments much easier to handle boat for berthing etc, no helm just the engines (on shafts anyway).

Plus if you have to hold it against a tide for instance to come alongside and between two other boats on the river then two engines invalueable to "walk sideways" as it were.
Clive

<hr width=100% size=1><A target="_blank" HREF=http://www.suncoastmarine.co.uk>Sun Coast Sea School & Charter</A>

hlb · 30 Dec 2003

"YM 'Ocean', Commercial Endorsement etc. Sail mainly + power.
30yrs+ experience, but still learning."

Yep get shut of the blinking eye!!

Well I dont know what he means by double props. But if he's been teaching folk about boats for thirty years. There going to be lacking a bit of knowledge.../forums/images/icons/smile.gif

<hr width=100% size=1> No one can force me to come here. I'm a volunteer!!.

Haydn

alant · 30 Dec 2003

Duoprops - not twin screws. Just want some figures.

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hlb · 30 Dec 2003

Well should have said that in the first place. Got every one else in a tither!! Dependes wot engines I suppose some will benffit some will not. Dont think adding two props to a rag thingy is going to help much though. IMHO.

<hr width=100% size=1> No one can force me to come here. I'm a volunteer!!.

Haydn

Dave_Snelson · 31 Dec 2003

Duo props give a massive thrust benefit on power boats. Are you intending single or twin engines? PM me if you want more details.

<hr width=100% size=1>Madoc Yacht Club
<A target="_blank" HREF=http://www.madocyachtclub.co.uk>http://www.madocyachtclub.co.uk</A>

Talon2 · 31 Dec 2003

Duoprops give about 15% more thrust than single props for same power. They do not suffer from 'prop walk' althought some people say this can be a disadvantage when trying to move the boat sideways. Of course 4 props are much more expensive to replace than 2. A good site to have a look at is:- http://www.shorelinemarina.com/service_center_.htm

<hr width=100% size=1>Keith

<A target="_blank" HREF=http://www.mobiledit.co.uk>http://www.mobiledit.co.uk</A>Edited by Talon2 on 31/12/2003 10:30 (server time).

Talon · 31 Dec 2003

<blockquote>In reply to:<hr>

Alex for goodness sake get rid of that awfull creepy thingy

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<blockquote>In reply to:<hr>

Yep get shut of the blinking eye!!

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Eye eye captain..../forums/images/icons/wink.gif

<hr width=100% size=1>Alex

Gtdog · 1 Jan 2004

Umm Duo props do prop walk, sorry to disagree with you.
The larger of each pair of props overcome the smaller and pull to starboard when reversing, nb this is more noticable on twin engine instalations.
This is also noticable in forward gear at speed on flat calm days as the boat will pull very gently to port, next time out pop it on auto and watch the response indicator.

That said, for most modern motor cruisers on outdrives the Duo Prop is a godsend, reducing fuel consumption by approx 10 - 15 % and giving far better acceleration than a single prop instalation.

The downside is that there are more components in the leg to go wrong, and removing a rope from a single prop outdrive is a walk in the park by comparison.

All the best,

George

<hr width=100% size=1>Work? You call this Work?

Talon2 · 1 Jan 2004

Yea agree with all you say, what I should have said is that prop walk is quite noticably reduced with douprops. Having had boats with both systems I much prefer the duoprops - just have to be prepared to pay more!!

<hr width=100% size=1>Keith

<A target="_blank" HREF=http://www.mobiledit.co.uk>http://www.mobiledit.co.uk</A>

alant · 1 Jan 2004

Thanks guys, most have reported useful stuff.

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PhilF · 2 Jan 2004

hoy, that's mine!!

PhilF

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Talon · 2 Jan 2004

Yes, sorry, I have removed it now. You have had it longer than me. /forums/images/icons/smile.gif

I just grabbed it as my eye was making people feel a little queasy!

You may keep the bobbing penis... /forums/images/icons/wink.gif

<hr width=100% size=1>Alex

<A target="_blank" HREF=http://www.mad-als.com>http://www.mad-als.com</A>Edited by Talon on 02/01/2004 19:12 (server time).

PhilF · 2 Jan 2004

I liked the eye!
Ta
PhilF

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Talon · 2 Jan 2004

Thnx, but I do not want to upset people, so I thought I would be all stiff upper lipped and have the British Flag. I was look for a blue ensign, but could not find one.

<hr width=100% size=1>Alex

hlb · 2 Jan 2004

It's OK. Borrow mine!!

<hr width=100% size=1> No one can force me to come here. I'm a volunteer!!.

Haydn

Talon · 2 Jan 2004

LOL

What the hell is that?

Now that is a flag to fly...... /forums/images/icons/smile.gif

<hr width=100% size=1>Alex

<A target="_blank" HREF=http://www.mad-als.com>http://www.mad-als.com</A>Edited by Talon on 02/01/2004 22:48 (server time).

Double screws

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