Reply
 
Thread Tools Search this Thread
 
Old 09 August 2009, 05:52   #11
CJL
Member
 
CJL's Avatar
 
Country: UK - England
Town: London
Make: Ribcrafts
Length: 5m +
Engine: 150hp/2x115hp
MMSI: 235090215
Join Date: Oct 2002
Posts: 2,115
RIBase
Send a message via Skype™ to CJL
__________________

__________________
www.northernexposurerescue.org.uk
A registered charity supporting events across England and Wales
Follow us on Vimeo and Facebook
CJL is offline   Reply With Quote
Old 18 August 2009, 14:03   #12
Member
 
Country: UK - Scotland
Town: Glasgow
Boat name: Thunder
Make: Halmatic Arctic 22
Length: 6m +
Engine: 2 x 150 Etec
Join Date: Oct 2008
Posts: 500
Ok so running with 14 x 22 props I'm getting 49 knots, revs at WOT are 5000 so i reckon with the props changed to 14 x 19's I should get up to full operating revs of 5800 and maybe get her through the 50 knot barrier. I have to say that that the power from the E-Tecs is amazing ).
__________________

__________________
GordyP is offline   Reply With Quote
Old 18 August 2009, 14:48   #13
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,013
Gordy,

The ideal top end operating range for the 150 is 5500 - 5600 RPM. I have my 150 propped to hit 5500 at WOT when fully timmed out. I did try an 18" prop and got 5650 and lost 3 knots.

I think you will be better off with 20" props. You may find you loose some top end speed with the 19's.

To gain RPM you may find that you can raise the engines on the transom as the E-tecs like to run quite high up. Did you check to see if your anti ventilation plates were riding above the surface?

Heres a picture of an E-tec mounted too low and then at the incorrect height...
Attached Thumbnails
Click image for larger version

Name:	toolow.jpg
Views:	194
Size:	33.9 KB
ID:	44993   Click image for larger version

Name:	correctheight.jpg
Views:	173
Size:	66.9 KB
ID:	44994  
__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 19 August 2009, 04:36   #14
Member
 
Country: UK - Scotland
Town: Glasgow
Boat name: Thunder
Make: Halmatic Arctic 22
Length: 6m +
Engine: 2 x 150 Etec
Join Date: Oct 2008
Posts: 500
Cheers Chris,

Going out tomorrow night with the usual load of divers and kit to see how she goes, good point on the vent plate, I'll have a check and see how she runs with weight on board. The engines have been set up so that the vent plate is in line with the bottom of the transom. Props that are currently on are ali, I want to make sure that I order the right stainless props!!
__________________
GordyP is offline   Reply With Quote
Old 19 August 2009, 16:27   #15
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,013
Quote:
Originally Posted by GordyP View Post
Cheers Chris,

Going out tomorrow night with the usual load of divers and kit to see how she goes, good point on the vent plate, I'll have a check and see how she runs with weight on board. The engines have been set up so that the vent plate is in line with the bottom of the transom. Props that are currently on are ali, I want to make sure that I order the right stainless props!!
Gordy,

To be honest I dont think you will see much more speed by dropping down in prop size however you are currently lugging the engine at 5000RPM so you do need to drop the prop size.

If your plates are currently level with the hull you may well be able to raise the engines at least 2 holes which could gain you 100-200RPM. A lot depends upon your hull and what props you end up getting. I would be tempted to go for 20" Vipers and see if you can also gain some RPMs by raising a couple of holes. Its a big decision to get right as the props are not cheap. If you wanted to borrow a 19" RH prop to try you are welcome to borrow mine then you just need to get hold of a LH one from someone else (assuming you are running contra rotating engines of course)

I have posted a question on the US based E-tec owners forum to see if any of the US or Australian guys who rig hundreds of twin installs of these engines can add any ideas.

Chris
__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 19 August 2009, 17:38   #16
RIBnet admin team
 
willk's Avatar
 
Country: Ireland
Make: Redbay Boats
Length: 9m +
Engine: 370hp
Join Date: Feb 2008
Posts: 12,925
RIBase
Quote:
Originally Posted by GordyP View Post
Ok so running with 14 x 22 props I'm getting 49 knots, revs at WOT are 5000 so i reckon with the props changed to 14 x 19's I should get up to full operating revs of 5800 and maybe get her through the 50 knot barrier. I have to say that that the power from the E-Tecs is amazing ).
I'm running 14 x 19 on 90s and getting about 4750 (ono ). Keep in mind that twins should be one notch overpropped compared to a single rig.
__________________
willk is offline   Reply With Quote
Old 19 August 2009, 17:50   #17
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,013
Quote:
Originally Posted by willk View Post
I'm running 14 x 19 on 90s and getting about 4750 (ono ). Keep in mind that twins should be one notch overpropped compared to a single rig.
Do you mean underpropped so if one engine quits the other should still have the grunt to get it on the plane?

If you do then you need to drop down a couple of inches becuase you are 250RPM below the optimum RPM for the 90's

E-tec RPM Chart
__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 19 August 2009, 17:56   #18
RIBnet admin team
 
willk's Avatar
 
Country: Ireland
Make: Redbay Boats
Length: 9m +
Engine: 370hp
Join Date: Feb 2008
Posts: 12,925
RIBase
Quote:
Originally Posted by Chris View Post
Do you mean underpropped so if one engine quits the other should still have the grunt to get it on the plane?
I don't think so, they just are . I think 'cos they're sharing the load so more Prop surface per HP to Load than a single, make sense?
__________________
willk is offline   Reply With Quote
Old 19 August 2009, 18:00   #19
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,013
Quote:
Originally Posted by willk View Post
I don't think so, they just are . I think 'cos they're sharing the load so more Prop surface per HP to Load than a single, make sense?
Not really
__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 19 August 2009, 18:00   #20
Member
 
Country: UK - England
Town: Manchester
Boat name: n/a
Make: n/a
Length: under 3m
Engine: n/a
Join Date: Apr 2009
Posts: 76
Quote:
Originally Posted by Chris View Post
Gordy,

The ideal top end operating range for the 150 is 5500 - 5600 RPM. I have my 150 propped to hit 5500 at WOT when fully timmed out. I did try an 18" prop and got 5650 and lost 3 knots.

I think you will be better off with 20" props......Did you check to see if your anti ventilation plates were
Erm.....what are.....ahem.....ventilation plates? Also, er.....does 18", 19" or 20" when that measurement applies to a prop. mean the distance it will travel forward during one full revolution? Or am I talking a load of bulls**t?

Walks away whistling nervously while everyone else on the Forum shakes their collective head.
__________________

__________________
The Beard 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 20:00.


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