Top speed sr 4.7/70hp?

tom's · 06 November 2011, 21:46

Hi, I think somebody's here have any experience of sr4.7 with 70 hp, so what what top speed can be achieve with this power?
Are 35/37 knots possibles?
What is the correct height of the outboard on the transom for good performances?

Thanks all.

Downhilldai · 06 November 2011, 21:54

Mine did around 35 kts with a Twatsoo 70.

Cav plate was 35mm above the keel

tom's · 06 November 2011, 22:03

With a Tohat TLDI or carb?
Do you remember what propeller had you?

Thank

Downhilldai · 06 November 2011, 22:09

Quote:

Originally Posted by tom's

With a Tohat TLDI or carb?
Do you remember what propeller had you?

Thank

Old skool carb 3 cyl 2006/7 motor, running a Turning Point Hustler 17" pitch 3 blade aluminium prop and making around 5500 RPM.

TLDi is too heavy for an SR4.7 with 20" transom.

whisper · 07 November 2011, 09:57

I got 35.5 knots out of mine and that was one up with two tanks of fuel and into a very strong head wind, so 35 - 37 sounds about right.

My outboard is fitted so the brackets are touching the top of the transom but it is offset around 2" to starboard.

tom's · 07 November 2011, 13:37

Thank you for your comments. Here in France, there is a compagny "Sillinger" who produce ribs with the same hull as the sr 4.7, look at this:Sillinger 490 RIBUM is a semi-rigid professional boat made by Sillinger, a professional and military boat specialist
These boats an specialy the 4.90 RIB UM is renowned here, essentiely used by sea anglers or for spearfishing.
Somes pictures:Sillinger 490

whisper · 07 November 2011, 14:38

I very much doubt if they are the same. The Avon Searider has now been re-launched by Zodiac with different tubes and console but the hull is still the same:

http://www.zodiacmilpro.com/wp-conte...-RIDER-4.7.pdf

Here is a link to the Avon website if you need any info on the Avon searider:

AboarD Boats & Yachts Market - SR4.7M Searider

whisper · 07 November 2011, 20:16

This thread may help:

http://www.rib.net/forum/f8/what-do-...ink-15149.html

tom's · 07 November 2011, 20:30

I'm absolutely sure that sillinger have produce and produce the same hull as sr 4.7. 2/3 year ago they produced also the 540 rib who had the same hull as the sr 5.4. When they had produce the first hull arround 1990, they adopted also the principe of the ballast. Since 2000, hulls are produced without this famous ballast.
I will try to post some pics of this hull...

Downhilldai · 07 November 2011, 20:35

Quote:

Originally Posted by tom's

Since 2000, hulls are produced without this famous ballast.

As were some Seariders

Quote:

Originally Posted by tom's

I will try to post some pics of this hull...

Look forward to seeing these.

tom's · 07 November 2011, 20:36

How can I post pics on this forum?
Whisper if you give me your E mail, i could send you some pics.
Thanks

whisper · 07 November 2011, 20:43

When you reply to a post go down to the 'Additional Options' at the bottom of the page, then click on 'manage attachments'

tom's · 07 November 2011, 20:52

Another solution, look at this, it's a French forum of Rib owners:
http://www.pneuboat.com/frames.php?u...hp&num_pp=1033
or this one:
http://www.pneuboat.com/frames.php?u...php&num_pp=275

whisper · 07 November 2011, 21:26

I know the answer

But I'm just about to sit down to dinner, so I'll let you know in a bit

Downhilldai · 07 November 2011, 22:28

The one in tom's first link is as near to a SR4.7 as you can get. It's only the tube fittings which appear different. Even the console is the same as a SR4.7.

Does anyone know where these are made? I saw some Sillinger RIBs in the Avon factory in Llanelli back in the early '90s, but they weren't Seariders.

whisper · 07 November 2011, 22:55

Yep, that looks like a 4.7....

Pic 1. My 4.7
Pic 2. sillinger 4.9

I think the reason they call it a 4.9 is because the tube design is longer due to the pointy end cones which are longer than the Later Avon design.

However the tube design on the sillinger looks very similar to my old 1990 SR4.7

whisper · 07 November 2011, 23:15

Here's a couple more...

Rogue Wave · 07 November 2011, 23:21

39 KNOTS GOT TWITCHY AT 36 AND TOOK ME QUITE A WHILE TO GET THE FEEL FOR 39

THAT WAS WITH A NOO 70 YAMMIE NO AFRAME AND i WAS ABOUT 3 STONE LIGHTER THEN

Downhilldai · 07 November 2011, 23:29

Quote:

Originally Posted by Rogue Wave

39 KNOTS........... i WAS ABOUT 3 STONE LIGHTER THEN

That wouldn't have been speed recorded by GPS then.

whisper · 07 November 2011, 23:34

Talking about 4.7s Stu, how are you getting on with yours? Are you up for a blast soon?