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Old 11 February 2013, 15:16   #11
hamster's Avatar
Country: UK - England
Length: 4m +
Join Date: Aug 2006
Posts: 196
I've used then on various boats used mainly as safety boats and can only report good things. Usually boats upto 5m which aren't at the higher end if their permitted engine rating. The fins allow the boat to plane a lot easier and at lower speeds even when loaded.
The also allow the boat to plane with out first pointing the bow at the sky if the boat isn't/can't be loaded properly as stated above.

I used a 4.5m rib recently for coaching in Chichester harbour which had them fitted. I could get on the plane easily with little power required and still stay below the 8kt speed limit which meant the boat handled a lot better when chasing dinghies with spinnakers up and used far less fuel than when I used the same boats a couple of years ago with out the fins fitted for a similar purpose.

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Old 11 February 2013, 17:31   #12
JamesF's Avatar
Country: UK - England
Town: Sidmouth
Boat name: Various
Make: Avon, Ribcraft
Length: 4m +
Engine: Mercury 40, Honda 50
Join Date: Nov 2012
Posts: 246
Fins did help a little on one of our boats, but really they were an only-slightly-effective workaround for the real problem, which was that a 25hp Mercury Bigfoot four-stroke is the wrong engine for an SR4.

Without an obvious problem to fix or work around, I'm not sure if I'd be inclined to start drilling holes. If there is such a thing as a clip-on set, they might be worth trying, if only to satisfy curiosity.

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Old 11 February 2013, 21:20   #13
Locozodiac's Avatar
Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
Join Date: Sep 2007
Posts: 1,706
In this particular case a 3.5 mtr rib using a 20 HP engine which matches perfectly that size rib should perform as expected without doel fins, trim tabs. If being underpowered, doel fins can help plane faster, anyway will need to have a well ballanced boat, engine perpendicular to water level and match perfect engine transom height to start with.

My actual 420 rib with a Tohatsu 2 strokes 18 HP rated for a 30 HP jumps on plane at only 3/4 throttle with me driving next to engine. As stated before try your combo as it is before going for doel fins, by the way are garbage, plastic bags, kelp collectors...

Happy Boating
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Old 14 February 2013, 16:47   #14
Country: UK - England
Town: Yeovil
Boat name: Gert Lush
Make: ribcraft
Length: 6m +
Join Date: Jan 2006
Posts: 82
I have been offered a set to test in a scientific trial this spring.
I intend to fit them to a 4.8 -5 m RC with a 60hp engine fitted.
The RIB is superb but we want to see if the fuel saving claims and extended planing speeds are true.
Keep you posted of our findings...
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Old 24 June 2013, 01:16   #15
Country: UK - England
Town: Greatham, Hampshire
Boat name: Sandy Alex
Make: sr4
Length: 4m +
Engine: Suzuki 55dt
Join Date: Jun 2012
Posts: 96
Hi Razzer,

did they help?

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