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Old 09 June 2015, 14:47   #51
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Originally Posted by Newto View Post
Tested this weekend with a new 15" prop, with three onboard and full tank got to 5100rpm running at 38mph so quite pleased with that! Thanks for your advice Dave, just need some warmer weather now!
😃😃

You're still a bit low on max rpm, you should be seeing 5600


.....sh1t happens.......
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Old 09 June 2015, 15:04   #52
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Like you say it looks a little unusual, but sounds like you have a good match. Do you mind me asking how much? Curious to see how well it might match my boat (Ribquest 6.3 with 2010 140 Suzuki) Tony T and I have been swapping notes about props recently as he has the same set up as me.
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Old 09 June 2015, 16:06   #53
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Compromise is the best solution, mine will never be a 40knot plus boat but now it feels happier and will maintain the great Redbay sea keeping capabilities. Win Win
Couldn't agree more. I'd happily sacrifice top end for handling any day. Give me a boat that will do 20-25kn in lumpy weather & a head sea, over a 45kn slammer anyday
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Old 09 June 2015, 17:42   #54
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Quote:
Originally Posted by RMS View Post
Like you say it looks a little unusual, but sounds like you have a good match. Do you mind me asking how much? Curious to see how well it might match my boat (Ribquest 6.3 with 2010 140 Suzuki) Tony T and I have been swapping notes about props recently as he has the same set up as me.

We will get to find out on the 27th Richard ... If he overtakes us he could have a battle on his hands


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Old 09 June 2015, 17:56   #55
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Interesting stuff. Think I'm going to let the engine bed in a bit (still only just over 20 hours on) before messing with the prop. We had 37knots on the GPS with 150 litres on board in Ireland but I don't think RBs are set up for speed: mine has a noticeable offset and is set quite low resulting in a bit of splashing round the transom.

As has been said before if I'd been concerned about top speed I probably wouldn't have bought a Redbay. Not ruling out playing with props later on though.
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Old 10 June 2015, 03:26   #56
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140 Horses

I think the problem is the Suz 140hp is not a true 140hp. When we had our 6.1mtr with a 150hp Jonnyrude and a 19" ballistic prop we would get 45kn+

My brothers RB 6.5mtr with a Suz 150 is good for 40kn with all the MCA code gear on board & the hull is a very heavy layup.
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Old 10 June 2015, 03:46   #57
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Interesting stuff. Think I'm going to let the engine bed in a bit (still only just over 20 hours on) before messing with the prop. We had 37knots on the GPS with 150 litres on board in Ireland but I don't think RBs are set up for speed: mine has a noticeable offset and is set quite low resulting in a bit of splashing round the transom.

As has been said before if I'd been concerned about top speed I probably wouldn't have bought a Redbay. Not ruling out playing with props later on though.
Dan, I'm in a similar situation to yourself, i.e. shaking down a new boat with a DF140. I have lifted my engine 2 holes from where it was set by Ribcraft. I had a lot of splashing around the transom, landing heavily on the port side after being airborne porpoising at high trim etc. Also the prop would cavitate badly to the point that the rev limiter kicked in, this was when landing after "catching air".
We took the boat to Whitby on Sunday after raising the engine & putting 25kg of sand in the bow. The weather was interesting, we headed north into a 2m head sea & the difference in handling was marked. The port list has gone, she lands straight & with no cavitation on landing, the prop bites straight away (I can't explain why lifting the engine would reduce cavitation, but that's props for you). It was too rough to try WOT, but I got her upto 5500.
I have the 21" ally prop on at the mo, which I think is about right. I got a SS as part of the deal, but we are waiting to decide which one to go for until we determine the ideal pitch.
Personally I prefer to run slightly underpropped as it gives better response in the rough for the sake of a few Kn at the top end. I'm a big fan of 4 blade props for the increased grip that you get, but I've not looked into them yet to fit the Suzuki. Unfortunately the Mercury Rev4 doesn't fit
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Old 10 June 2015, 04:24   #58
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My drive and goal was improved grip

I was I guess just underwhelmed with the engine performance, I could not trim out more than half before the prop cavitated and this was with the mix of props I tried.

My engine was also low set when I bought it, I have moved the engine up one hole (mainly because of the jet ski style spray coming up from the transom! the engine is still a touch lower than the keel so grip is not compromised but spray is dramatically reduced.

If you do turn fast now with some trim and you get some cavitation then you just trim in and the prop recovers very quickly, previous prop would need speed to be reduced and trim in before you get the grip back.

The handling has always been great with a soft neutral
ride but I put that down to the hull design, layout with the console well up front and the large 150 litre tank under deck. (And the heavy skipper) this is hence why the boat will never be the fastest, again we did not buy the RB for this.

Now the engine will trim out way past half way without losing grip, gaining some extra speed, but more importantly it feels to me as if it is normal now as it should have been before if this makes sense. Would have been interesting to try the prop with engine in it's lower position, but it's all siko flexed in now.

I also understand that the newer RB 6.1's are lighter now so not so much oomph is needed.
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Old 10 June 2015, 04:39   #59
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Separate question

Quote:
Originally Posted by Dan Gurney View Post
Interesting stuff. Think I'm going to let the engine bed in a bit (still only just over 20 hours on) before messing with the prop. We had 37knots on the GPS with 150 litres on board in Ireland but I don't think RBs are set up for speed: mine has a noticeable offset and is set quite low resulting in a bit of splashing round the transom.

As has been said before if I'd been concerned about top speed I probably wouldn't have bought a Redbay. Not ruling out playing with props later on though.
Very jealous of your new boat, do you have any pictures, layout, colours etc, I also understand that the newer df140 engines have a very different final drive and being lighter should perform better.

Sounds like yours is pretty close to perfect, with that much fuel 37knots is great.
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Old 10 June 2015, 04:53   #60
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Quote:
Originally Posted by RMS View Post
Like you say it looks a little unusual, but sounds like you have a good match. Do you mind me asking how much? Curious to see how well it might match my boat (Ribquest 6.3 with 2010 140 Suzuki) Tony T and I have been swapping notes about props recently as he has the same set up as me.
Will send you both a pm, will bring the prop with me,
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