Tiller trim

tellum · 17 February 2019, 11:10

Hi, I have just PX my Sib for my first rib. I have gone with a ocean runner 420 to start me off. Now I like the open boat approach for my fishing gives me lots of space. I have reserved a 8 month old 20 HP to go with it. Should give me 20 knots maybe a bit more . which is more then I got from my t40 Sib with a 20 on. But my mind telling me to get a 30 just incase. . so my questions are would a 30 give me that much extra? 9 times out of 10 I will be on my own. Also would power trim be worth having on the tiller. I generally fist off Cornwall coast probably no more then 5 miles out. Thanks

spartacus · 17 February 2019, 12:21

Go with the transom rating. You can have power and not use it. Useful if the boat is loaded up too.

tellum · 17 February 2019, 18:35

ya wouldn't hurt to have a bit more i suppose, although with power trim and electric start on the multi functional tiller its around 2 grand more. its the use of the power trim , normally on my sib just stick it in second hole and it done the job. will a rib be any different ?

chipko · 17 February 2019, 18:43

Tellum,

As the Ocean Runner 420 is rated up to 40hp then the bigger the motor the better would be my advice.

In terms of power trim/tilt and ignoring cost;

Portable outboards, up to and including 20hp, weight is paramount. Motor on and off transom, boat not trailered, so lightest option... no power tilt/trim, no electric start, no battery. Simples.

Medium outboards 25hp and up, not portable, motor lives on transom, boat lives on trailer. No benefit not having electric start, power tilt/trim, battery. Simples.

A more detailed answer available on the other channel.

Limecc · 07 August 2019, 03:30

Quote:

Originally Posted by tellum

I have reserved a 8 month old 20 HP to go with it. Should give me 20 knots maybe a bit more . which is more then I got from my t40 Sib with a 20 on. But my mind telling me to get a 30 just in case..
so my questions are would a 30 give me that much extra?

How did you get on in the end?
I can answer your question precisely, a lightly loaded 420 with Mercury 30 (s/s 11P prop) will give you 29.5 knots @ 6200 rpm correctly trimmed on the open sea. With two people drops to 26 knots @ 5800 rpm.

Looking forward to trying a 40, just need a few weeks to run it in now it's fitted..

Locozodiac · 07 August 2019, 17:40

A 420 with a 30 HP motor is enough for solo and 2-3 up as well, a 40 is an HP excess. Be aware that heavy 4 strokes larger motors with electric start and trim will stress the transom badly if tubes are not working well inflated to the factory recommended working pressure when in use.

Happy Boating

Limecc · 07 August 2019, 19:29

Quote:

Originally Posted by Locozodiac

A 420 with a 30 HP motor is enough for solo and 2-3 up as well, a 40 is an HP excess. Be aware that heavy 4 strokes larger motors with electric start and trim will stress the transom badly if tubes are not working well inflated to the factory recommended working pressure when in use.

Happy Boating

I have to disagree. Heavily loaded with some heavy people it was reluctant to get on the plane and struggling to make over 20 knots. The 460 version is rated to 60 HP though only 0.4m longer and appears to have the same transom which is obviously strong enough..

There's a law of diminishing returns though (i.e. bigger heavier boat needs bigger engine to do same speed) everyone finds what works for them personally in the end.