Reply
 
Thread Tools Search this Thread
 
Old 28 April 2017, 07:07   #11
Member
 
Country: UK - England
Town: Towcester
Boat name: Treliska
Make: Ribcraft
Length: 6m +
Engine: Outboard 225 Optimax
MMSI: 232009522
Join Date: Feb 2006
Posts: 187
RIBase
Quote:
Originally Posted by cornishcoote View Post
Another more concerning point was it doing the dreaded chine walk. Spoke back to the guy who fitted and he said raise it up one hole on the transom? Another thoughts?
Generally the boat is starting to chine walk because it's running too much bow-up, shortening the wetted length. Moving the engine up will mean you have slightly less trim authority (i.e less bow up for any ammount of engine movement) but that's not really a direct solution. The answer is don't trim up quite so much at high throttle settings, and/or add more weight to the bow (or the boat overall). In the right conditions anything with a high power-length ratio can be persuaded to chine walk.
__________________

__________________
Andy_Rs600 is offline   Reply With Quote
Old 28 April 2017, 08:25   #12
Member
 
Phil M's Avatar
 
Country: UK - England
Town: Whitehaven
Boat name: Pegasus
Make: Zodiac Pro 530
Length: 5m +
Engine: 115hp Merc 4st
Join Date: Oct 2012
Posts: 336
I have a 530 Pro (1988 vintage) with a new Mercury 115 that's been on for about 18 months. It is an excellent engine. Very quiet even at full chat, fairly frugal and very light for the power (less than a 115 opti). I get about 41mph on full throttle and just over 5200rpm with a 17" prop, so with a change could give a little extra. Hole shot is fantastic and I generally burn about 1.3kn per litre. I've had no chine walk issues but my hull is almost a trimaran (really large reverse chines) which keeps it stable but adds drag. I paid the extra and got the smartcraft gauge upgrade, which i'm very happy with as it gives a lot more monitoring on the gauges and more engine sensors, plus will link to fuel gauge and gps to give you expected fuel range. Fitting was quite easy, for the engine at least although some of the additional sensors needed careful thought as the instructions weren't great.

Hope this helps,

Phil M
__________________

__________________
Phil M is offline   Reply With Quote
Old 28 April 2017, 09:58   #13
Member
 
Country: UK - England
Town: St Austell
Boat name: On Site
Make: Zodiac
Length: 5m +
Engine: 100hp outboard
Join Date: Oct 2015
Posts: 34
RIBase
Thanks for this.
So it's a 20" long shaft outboard.

I've just been and chatted to my local marine mechanic and he has leant me a 19" prop. He will also let me use his hoist to raise it if need be.

I noticed that the trim was a lot more sensitive compared to my last engine which may indicate it's a bit low?

Wellhouse. Your bang on with the weight. I went from 168kg to 180 kg with the new engine.
__________________
cornishcoote is offline   Reply With Quote
Old 07 May 2017, 16:45   #14
Member
 
Country: UK - England
Town: St Austell
Boat name: On Site
Make: Zodiac
Length: 5m +
Engine: 100hp outboard
Join Date: Oct 2015
Posts: 34
RIBase
Advice on Re-powering Zodiac Pro 550 Rib

Bit of an update after another sea trial today.

I decided to raise the engine up one hole this time and ensured the rib tube pressures were good before testing again.

I had the 19" s/steel prop fitted this time and all seemed good. Got up to 42mph (gps) and although, when flat out, it still had a bit of chine walk, this could now be trimmed out. She then settled well.

Might try a 21" prop as was still going just a smudge over the 6k rev limit, but I did have a light load. Hole shot was awesome.

Thanks for all your advice.
__________________

__________________
cornishcoote is offline   Reply With Quote
Reply

Tags
rib, zodiac

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 16:42.


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