Reply
 
Thread Tools Search this Thread
 
Old 22 August 2006, 13:55   #1
Member
 
Country: UK - England
Town: West Sussex
Make: zodiac
Length: 6m +
Engine: suzuki 115
Join Date: Jul 2006
Posts: 101
Wrong Prop

Couldn,t wait any longer to try out the new prop ,and after seeing the dismal forecast for the week decided that i would take the day off Tues ,as it seemed the best day .
I was told by steel developments when i enquired about this particular prop to expect a drop of 400 rpm this i thought would be ok as engine revs a shade to high anyway.So carrying normal load of fuel and bodies and the great conditions off we went.Our passage through Chichester harbour seemed to take forever but eventually was able to put the hammer down so I did ,and I waited and waited and eventually she dragged herself up to the dizzy speed of 31.5 knts at 5000rpm wot . Ive lost 1000rpm and 8 bloody knts the only plus side to this miserable affair that it does hold it in the turn a lot better .So will call steel devs in the morning and see what we can do .
__________________

__________________
toby4594 is offline   Reply With Quote
Old 22 August 2006, 14:16   #2
Member
 
Cypman's Avatar
 
Country: UK - Isle of Man
Town: Douglas
Length: no boat
Join Date: Aug 2006
Posts: 337
Sorry to hear it did not work. I have a DF140 with a standard aly prop of 21 ins pitch. Its WOT is 6000rpm which is mid way between the recommended 5600-6300 max rpm. As my boat is used primarily for cruising and I didn't need maximum acceleration I ordered a 22 in pitch S/S prop from Suzuki, unfortunately it also "failed" so I am looking to try the 20 in one.
I believe you need to swap the 23 in prop for a 21 in one and see what happens. Realistically, a 2 in change should give you about 500rpm difference. However, props have a mind of their own!!! Trial and error seems to be the best alternative, good luck
__________________

__________________
Cypman is offline   Reply With Quote
Old 23 August 2006, 03:37   #3
Member
 
Ribshop's Avatar
 
Country: UK - England
Town: River Hamble
Length: 6m +
Join Date: Oct 2005
Posts: 726
Funny you lot seem to be having similar problems to what we have experienced with the Suzuki’s.
We rigged some 140s on 6.5m’s, the props supplied by Suzuki were absolutely useless! Cavitation was the worst I have ever experienced! After speaking to Suzuki who I have to say were about as useful as a chocolate fire guard we were no closer to solving the problem.
In the end after putting nearly £15k in Suzuki’s pocket we took the problem on our selves to sort out.
We ended up going from a Suzuki 23’’ stainless steel prop that cost an arm and a leg, to a Turning Point 23’’ (aluminium) that cost les than £65. We took 1’’ of the pitch and its perfect, no slip, better pick up and a far better top speed.
__________________
RIB REPAIRS | RE-TUBES | RE-FIT - OUTBOARD SERVICING - ONLINE SHOP FOR RIB & TOHATSU PARTS .
Phone: 01489 556800 www.rib-shop.com
Ribshop is offline   Reply With Quote
Old 23 August 2006, 04:29   #4
Member
 
Country: UK - England
Town: Southampton
Boat name: Blue Temptress
Make: Shakespear
Length: 5m +
Engine: 200 Promax
MMSI: 235037862
Join Date: Jun 2005
Posts: 21
I also have a DF140 and have a S/S 21" prop, WOT gives me about 5500rpm and a speed of around 43knts.

I was actually wanting to try a 19" prop to see if I could get a little more top end out of it.

Sorry guys, I'm not a ribnobber, but a hard boater, but I do like ribs, honest

The engine is rigged to a Shakesphere 610/Ring 20 hull.
__________________
Lasermatrix is offline   Reply With Quote
Old 23 August 2006, 05:27   #5
Member
 
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,962
Quote:
Originally Posted by Lasermatrix
I also have a DF140 and have a S/S 21" prop, WOT gives me about 5500rpm and a speed of around 43knts.
That's a slip of -7.66.......

Quote:
I was actually wanting to try a 19" prop to see if I could get a little more top end out of it.
You wont but you might get a better lower end.
__________________
JW.
jwalker is offline   Reply With Quote
Old 23 August 2006, 06:13   #6
Member
 
Country: UK - England
Town: Southampton
Boat name: Blue Temptress
Make: Shakespear
Length: 5m +
Engine: 200 Promax
MMSI: 235037862
Join Date: Jun 2005
Posts: 21
Quote:
Originally Posted by jwalker
That's a slip of -7.66.......
*wanders off grumbling about inaccurate readings*

Hmmm, methinks I had better check my RPM guage out

Negative slip....that's not supposed to happen
__________________
Lasermatrix is offline   Reply With Quote
Old 23 August 2006, 14:44   #7
Member
 
Country: UK - England
Town: West Sussex
Make: zodiac
Length: 6m +
Engine: suzuki 115
Join Date: Jul 2006
Posts: 101
Called steel devs today, was hoping that they would have been a bit more helpful the best they can do is a 1" repitch at half price so down to a 22". Original cost with postage and the dreaded £304-00, repitch plus postage both ways approx £48-00 Costly prop this. Theres a lesson here, beg ,borrow or steal prop to try before you buy.
__________________
toby4594 is offline   Reply With Quote
Old 23 August 2006, 15:03   #8
Member
 
Hightower's Avatar
 
Country: UK - England
Town: Fareham
Length: 6m +
Join Date: Sep 2003
Posts: 7,855
Sorry to hear of your problems, it's always is better to borrow or even buy second hand. If you want to try a different prop then a Thread here asking if anyone is local and can help is always worth a try first.

I was lucky and bought a couple of differently pitched brand new alloy props back from a trip to the States and after a very kind Gent from Port Solent let me brorrow a couple of SS ones I had made my choice. After I selected the ones I wanted I sold off the props I didn't want and acually made some money.

Toby I have a 90 on a 5.3m RIB and can't run anything over a 17" alloy prop. Would a 19" SS prop be better for you?
__________________
Andy

Looks Slow but is Fast
Member of the ebay Blue RIB cover club.
Hightower is offline   Reply With Quote
Old 23 August 2006, 17:11   #9
Member
 
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,962
Quote:
Originally Posted by toby4594
Theres a lesson here, beg ,borrow or steal prop to try before you buy.
And don't trust what someone who is about to make money out of you, tells you.
__________________
JW.
jwalker is offline   Reply With Quote
Old 23 August 2006, 17:50   #10
Member
 
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,962
If I may make an observation here; I'm not familiar with the Suzi 140 but I feel you guys are maybe thinking in the wrong direction. The motor is about 2lt, normally aspirated and 140hp. That's a good power from a smallish engine and I'd bet the low end torque is not particularly high so the power delivery is going to be a bit peaky. Since most of the time you're not likely to be driving flat out, why not prop the motor for good low to midrange performance, ie. good holding, good acceleration, good grip while climbing the back of a wave etc., all the things ribs should excel at? If it were me, I'd be aiming to choose a prop which runs close to maximum revs when flat out, which I believe is 6200rpm.

Cruising revs will be a bit higher but the throttle will likely be less open because the engine will be lighter loaded and I'd bet you'll see very little difference in fuel consumption. It could even be better. Over pitching for relaxing cruise is a bit like leaving your car in too high a gear for most of your driving and when you come to the hills, you're fekked. It's also not best for the engine.

I used to have the Suzi 200 which was 2.7lt and a long stroke hence high low/mid torque and it's outstanding, and very satisfying, characteristic was mid range grunt. It gave me far more driving pleasure than an extra knot flat out.

It was the same motor that Codprawn has and although I've never spoken to him I'll bet he will confirm my experience.

So, forget the top end, get the midrange right it's just better boating.

Now, the new 150hp Suzi looks interesting cos it's 3ltr. Just 10hp more but I bet it pulls like a train.

Just my thoughts.
__________________

__________________
JW.
jwalker is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 08:41.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.