Avon Searider 4mtr, Mercury 50hp 2 stroke prop

[SR4]

Hi, I would like to hear anyone's experience of propping a 50hp on a Searider 4mtr. I have just bought one with an unidentifiable prop, it has great hole shot but max is 34knt, it has seen better days so have just bought a new prop on advice of experienced shop owner, but on arrival it looks a lot smaller and pitched shallower than the existing prop, so before I launch what should I expect to happen?

I have just bought a rev counter do not fitted yet, but just wanted a rough idea as to what to expect with a 1" smaller diameter prop and shallower (flatter) 15" pitch, new prop is a Mercury Black Max 10 1/8 x 15 pitch in AL.

Thanks,

[Nos4r2]

Which Merc 50 2 stroke is it?

[SR4]

1999 3 cylinder

[Nos4r2]

Originally Posted by SR4

1999 3 cylinder

Bigfoot or normal?

[SR4]

Normal

[Nick Hearne]

If you are getting 34knots in my experience that will be about it, I have a Yam 50hp 2st & 33knots is about it, although some one from the USA recons he is getting 50knots ????

[PeterR]

Originally Posted by Nick Hearne

If you are getting 34knots in my experience that will be about it, I have a Yam 50hp 2st & 33knots is about it, although some one from the USA recons he is getting 50knots ????

I think he may have left his sat nav on when he towed it home.

[ollyit]

it'll chine walk like a bitch much faster than that - sounds about right - had a 15" merc one on and 17" standard yamaha alloy on mine - 50knots is just bollocks

[SR4]

Thanks for the replies, I have searched the site and looked in awe at the 50knt report, I doubt I could reach that speed even with wind and tide.

Anyhow, went out in the Solent today, a bit lumpy and was 2 up for safety, we also had twin 25ltr tanks on board so a good bit of weight. The new prop seemed good, I don't think I quite got the same hole shot speed but as I said I had a passenger and an additional 25 ltr of fuel, it was force 6 gusting 8 so just ploughed through although occasional blasts produced stunning performance. Tomorrow looks better with force 3 gusting 5 so will head out again and report back.

[Nos4r2]

IF it's the same gear ratio as my old '93 50hp non-bigfoot Merc on my old SR4, I got 44mph (or about 39 knots) with a 10 3/8x14" prop on it, solo but it dropped to about 34 knots 2 up.

50 knots is utter bull. At 39 knots I was just the other side of the chinewalking on oil calm water.

[Max...]

Originally Posted by SR4

Thanks for the replies, I have searched the site and looked in awe at the 50knt report, I doubt I could reach that speed even with wind and tide.

Anyhow, went out in the Solent today, a bit lumpy and was 2 up for safety, we also had twin 25ltr tanks on board so a good bit of weight. The new prop seemed good, I don't think I quite got the same hole shot speed but as I said I had a passenger and an additional 25 ltr of fuel, it was force 6 gusting 8 so just ploughed through although occasional blasts produced stunning performance. Tomorrow looks better with force 3 gusting 5 so will head out again and report back.

You're a brave man going out today - spoke to the RNLI boys towing the boat out at Rye this morning and they turned back...

[SR4]

It was rough but been out in worse, I popped into Langstone harbour, there were sailing dinghies out plus their safety boats so not impossible conditions although the route to Bembridge required some concentration. Off out again tomorrow for some fun.

[SR4]

Originally Posted by Nos4r2

IF it's the same gear ratio as my old '93 50hp non-bigfoot Merc on my old SR4, I got 44mph (or about 39 knots) with a 10 3/8x14" prop on it, solo but it dropped to about 34 knots 2 up.

50 knots is utter bull. At 39 knots I was just the other side of the chinewalking on oil calm water.

Well I am 135kg and my mate must be 90kg plus 50ltrs fuel, so we didn't have a hope in hell getting 39knts with the wave height. Will go solo tomorrow and open it up, I fitted a rev counter this afternoon, original back illuminated one and harness, from first test it ticked over at 1k and topped at 3.5k. Only problem is I had to fit it under the steering wheel due to lack of space so not the best place to get a good view, although perfect to see your nuts :-).

[SR4]

Originally Posted by SR4

Well I am 135kg and my mate must be 90kg plus 50ltrs fuel, so we didn't have a hope in hell getting 39knts with the wave height. Will go solo tomorrow and open it up, I fitted a rev counter this afternoon, original back illuminated one and harness, from first test it ticked over at 1k and topped at 3.5k. Only problem is I had to fit it under the steering wheel due to lack of space so not the best place to get a good view, although perfect to see your nuts :-).

Sorry, should read topped out at 5.5k