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Porpeller

Printed From: The Solent Fishing Forums
Category: Fishing Forums
Forum Name: Boat Talk
Forum Description: This forum is for anything related to local boat fishing
URL: http://www.solent-fishing-forums.co.uk/forum_posts.asp?TID=5676
Printed Date: 17 August 2018 at 8:30am


Topic: Porpeller
Posted By: TideFlow
Subject: Porpeller
Date Posted: 21 February 2018 at 7:03am
Hi all

Can anyone recommend a company I can speak to ref re-propping my boat?

I have done the usual "googling" but there are a few out there but I'm not sure who is the best to speak to.

I did a good run to the Needles last weekend and I'm fairly convinced the boat is over-propped. She currently has a 19 pitch on it and I should be pulling between 5000-6000 rpm WOT.

We were 3 fairly weighty guys with our gear and WOT was 4600 rpm. I think she has been propped as an empty, clean boat but as this is not the configuration I would normally be running in I think I would benefit from fitting a lower pitch. She does take a time to get out of her hole but when finally up on the plane she does fly (25kts) which is the maximum rated for the hull with a 115hp on the back.

Could do with an experienced person to run through all this and see what their thoughts were on the correct prop for me.

Apologies for the waffling....



Replies:
Posted By: Ahab
Date Posted: 21 February 2018 at 7:32am
is it outboard or shaft


Posted By: TideFlow
Date Posted: 21 February 2018 at 11:57am
It is an outboard


Posted By: Ahab
Date Posted: 21 February 2018 at 12:04pm
sorry cant   help


Posted By: Doombar Dave
Date Posted: 21 February 2018 at 12:31pm
If it helps my Parker 660 has a Suzuki 115 on the back of it and has a 19inch pitch prop which it runs fine with normally I run at about 4000 to 4500 rpm with it seems comfortable at and is doing about 20/22 knots and will run up to 6000 rpm if needed

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Parker 660 AmyJames


Posted By: Whitewash
Date Posted: 21 February 2018 at 1:08pm
Is that your Parker 660 in Southsea marina just below the café ?

Very nice if it is!



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David Cox
"Whitewash"
Itchenor


Posted By: Doombar Dave
Date Posted: 21 February 2018 at 3:54pm
No think that one is Rays, keep mine at Gosport it is one of the older white and blue ones.
Originally posted by Whitewash Whitewash wrote:

Is that your Parker 660 in Southsea marina just below the café ?

Very nice if it is!



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Parker 660 AmyJames


Posted By: Ahab
Date Posted: 22 February 2018 at 8:38am
yes that's me as close to the bar as I could get nice to have a quick pint while flushing the out   board


Posted By: Alanr
Date Posted: 22 February 2018 at 8:59am
Is it on a quicksilver 640 as my mate has the same 19 pitch and has the same problem with his , mariner 115 powered


Posted By: Electric Blue
Date Posted: 23 February 2018 at 9:53am
Have you tried Hamble propellers, down Swanwick, or if as it's a suzuki, Lee Fairweather in Fareham??

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Electric blue - colvic seaworker


Posted By: TideFlow
Date Posted: 23 February 2018 at 10:16am
Thanks for that, I will give Hamble propellers a call, I did think of Fairweather as I live 5 mins from them but when I googled them they don't deal with Mercury's.


Posted By: Ahab
Date Posted: 23 February 2018 at 10:22am
sussex boat yard service my merc 150


Posted By: TideFlow
Date Posted: 23 February 2018 at 10:24am
Originally posted by Alanr Alanr wrote:

Is it on a quicksilver 640 as my mate has the same 19 pitch and has the same problem with his , mariner 115 powered


It's on a Merry fisher Marlin 6 and I'm running a 100hp Mercury. She will plane empty and achieve 25kts, I would have thought with the 100hp I should get a little bit less than the rated 25kts with a 100hp. It's as soon as I load it with gear that I am at nearly full throttle to get it planning. I am contemplating a 4 bladed prop as well.


Posted By: billy the fish
Date Posted: 24 February 2018 at 11:00am
is it a 2 stroke motor or a 4 stroke 13.25x17 will be the next size down and will prob get you into the lower recommended rpm range or 15 pitch for more, also alloy or stainless prop 

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if you have to measure it, its too small!!


Posted By: TideFlow
Date Posted: 26 February 2018 at 6:17am
Hi Billy

It is a four stroke and I am going to stick with an alloy prop.


Posted By: TideFlow
Date Posted: 26 February 2018 at 6:52am
Did some test runs on Saturday,

Engine rated at 5000-6000 rpm WOT

With 2 adults and some but not all of my gear on board we achieved 4700rpm, My normal running configuration would be with another large adult and the associated gear on board.

Personally I think she has been propped for top end speed as the guy who I purchased form had hardly any gear and fished solo most of the time.

For me I will 2-3 anglers at all times and we have a fair amount of gear.

I want to achieve a quicker plane time and good cruise performance as this is what she will spend 99% of her time doing.

99% sure I am going to go down the 4 blade prop route.



Posted By: billy the fish
Date Posted: 26 February 2018 at 6:35pm
have never tried a 4 blade, what pitch are you fancying?

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if you have to measure it, its too small!!


Posted By: billy the fish
Date Posted: 26 February 2018 at 6:39pm
been playing with props on mine and have made the decision to have a alloy re pitched to a 13 1/2 x 18 with a bit of rake as well, am hoping it will be the perfect set up then Big smile 

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if you have to measure it, its too small!!


Posted By: TideFlow
Date Posted: 27 February 2018 at 6:18am
She is currently running a 19" but after speaking to Hamble propellers and the local Mercury dealer, to get the RPM right I need a 15"-16" pitch.

Unfortunately the 4 bladed props available off the shelf are either 17" or 14" either too little or too much, so after much deliberation I am going to go with a larger diameter 3 bladed prop of 15" pitch.

Actual size being 15.5x15


Posted By: rag & stick
Date Posted: 27 February 2018 at 11:41am
Just a thought do you have trim tabs fitted, going back to my day of fast motor boating I was advised to to fit them and it made all the difference with getting on the plane quickly and keeping the boat level.


Posted By: billy the fish
Date Posted: 27 February 2018 at 6:19pm
thats a fair diam size,you must have a big gearcase on your motor  

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if you have to measure it, its too small!!


Posted By: TideFlow
Date Posted: 28 February 2018 at 3:09pm
rag&stick I don't have trim tabs fitted, it is something I have thought about but am going down the prop route first, I am definitely over-propped and that needs sorting. If I continue to have issues I will look at tabs

Billy Looking in the official Mercury book with the dealer there are a loads of props that will fit on my engine the 16" diameter being the largest that will go on


Posted By: Ahab
Date Posted: 28 February 2018 at 4:36pm
I must say I had trim tabs fitted on my parker


Posted By: Salar
Date Posted: 28 February 2018 at 10:50pm
Good bit of advice from Bennetts Trim tabs:

Using Your Power Trim and Trim Tabs Together
Prop-a

It is a common misconception that if a boat has power trim on the outboard or outdrive it does not need trim tabs. Yes, power trim can be used to adjust the boat’s attitude, but it is highly inefficient.

This is because a propeller is designed to force the boat forward. When trimming the boat with the prop, the prop must not only push the boat forward but raise the stern as well. In this situation, prop slippage is greatly increased thereby wasting RPMs. Power trim also cannot correct listing, and is ineffective at slower speeds.

For increased speed and power, use your trim tabs WITH your power trim. Bennett Trim Tabs, in combination with power trim, enable both the hull and prop to be trimmed independently. The trim tabs trim the hull, while the power trim adjusts the prop. The result is optimum performance and efficiency not attainable by the use of power trim alone.

To achieve maximum performance:
1. Adjust the trim tabs to achieve a planing attitude.
2. Use the power trim to position the prop path parallel to the water flow.
3. If necessary, re-adjust the trim tabs to “fine tune” your tabs. In other words, use your trim tabs to trim the boat and your power trim to trim your prop.



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Harley 25 "Rebel Runner"
web site www.boat-angling.co.uk


Posted By: Osprey Oldman
Date Posted: 01 March 2018 at 12:38pm
That's a very well explained bit of advice Neville.
Thanks for posting it.


Posted By: TideFlow
Date Posted: 31 March 2018 at 7:55am
Just a bit of an update on the prop, We decided to go for a 15" pitch in the end.

The result being another 1300rpm (topping her out at 6000rpm) which is bang on the limit for a light clean boat (our calculations have worked out she should drop to roughly 5500rpm when I'm loaded for fishing)

Gained another 3kts so now get 27.5kts WOT. More importantly my cruise rpm is 4100rpm but this comes at a lower throttle setting so should see a small reduction in fuel consumption, roughly working out at 20 l/ph down from 24 l/ph




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