New sib problem

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Fishfinder Great Britain
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New sib problem

Post by Fishfinder » 17 May 2020, 15:55

Hi guys, I’m new to sibs and any kind of boating except kayaking, here goes, first time out yesterday in my new sib, due to obvious reasons, 3m telamex sunsport and 6 HPI tohatsu, I’m sure that I’ve overlooked something on the outboard as when I’m only at half throttle the front of the sib is looking at the sky!!!? Hence I can’t see a bl##dy thing in front of me :o ive attached a picture of the settings on the outboard and hopefully someone out there can let me know where I’ve gone wrong.
Thanks
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harrison Great Britain
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Re: New sib problem

Post by harrison » 17 May 2020, 16:50

Hopefully nowt wrong.

Sounds like your not quite getting on the plane and stuck ‘climbing out the hole’

This is where you’re going too fast to be at displacement speed (hull fully in the water) and too slow to be fully on the plane (hull riding on top of water). Being stuck on no mans land in between just means the bow points skywards.

With 6 horses on a 3m boat it may be marginal in some conditions to get on the plane if heavily loaded, but doable most of the time. Get some weight in the bow such as anchor, kit and fuel etc. to help trim.

So, try giving it max throttle, the bow will initially rise, move your weight forward to help boat climb out of the hole, hopefully bow will drop and level out. You are now on the plane and can probably reduce revs a little and move your weight back whilst still remaining planing.

Altering the trim of the motor will have an effect on ride angle, but for now wouldn’t get too hung up on that. Running it on second or third hole out should be in the right ball park initially.
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Martin England
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Re: New sib problem

Post by Martin » 17 May 2020, 18:34

As above, a great explanation..
perhaps it’s just my weight and the Suzuki outboards I’ve always had,maybe even the load I have, but I never seem to get a better trim setting than the 1st hole..

Q1 ..
Is it an air floor or aluminium floor ?
6hp on an ally floor bloat is a big ask.

Q2, what sort of weight was in the boat, you-gear-fuel ?

Martin :cheers l
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Re: New sib problem

Post by Fishfinder » 17 May 2020, 19:31

Thanks for advice guys, it’s an air floor, full tank of gas placed at the front and a couple of rods, as in photo the motor is on the second hole so next time I go out I’ll try it on the first, I don’t want to give it full throttle at moment as it’s not yet run in, :thumbsup

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ChrisParish Great Britain
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Re: New sib problem

Post by ChrisParish » 17 May 2020, 21:22

To understand what is happening it helps to understand how the boat moves through the water.

If you are not on the plane, then your maximum efficient speed is dependent on the length of the boat. The maths is complex but it boils down to max speed = 1.34 x square root of length of the boat at the waterline in feet.

Given that your boat is 3m long, let’s assume that 2.8m of it is in the water, with just a bit of the bow out of the water. That puts your max speed at 4 knots.

The boat goes through three stages as you speed up: efficient displacement, where your speed is below 4 knots. This is your most efficient displacement speed where you will get the best low speed economy and the quietest ride as engine speed and water noise will be low.
The next stage is plowing (there may be other names). At this speed a large wave builds up under the bow, pushing the bow up. This is the least efficient speed as you are using the power of the engine to push a large volume of water out of the way. Generally I would try and avoid this speed range as it eats fuel and is loud.

Finally there is planing. this is the speed at which your boat has climbed the wave that was created during the plowing phase and it is now riding on top of the water. Your best overall fuel economy will be in this speed range, typically about a third of the way between the lowest planing speed and wide open throttle.

Why is all this relevant, you may ask?
Basically, in reference to your original post - if the bow is right up in the air then you are in the plowing phase and should either speed up or slow down. I see many people trying to shove their boats along at inefficient speeds but all this will do is to use fuel, make noise and lots of wake.
Given that you are still running in then I would just slow down a bit to bring the bow down.

There are times where you might want to bring the bow up, for example if it is choppy.

So when you are going at displacement speed and you feel that adding power isn’t actually making you go any faster, drop the power until you notice the boat start to slow and stay at the speed.

I suspect I may have started to ramble.
I hope this helps and makes sense.
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Fishfinder (17 May 2020, 21:41) • RONHAS (18 May 2020, 11:00) • Sibfisher (18 May 2020, 16:13) • IanH 72 (02 Jun 2020, 14:36) • Tyger (17 Feb 2022, 07:54) • Tequila (21 Aug 2023, 14:12)
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RONHAS Portugal
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Re: New sib problem

Post by RONHAS » 18 May 2020, 11:02

Great explanation for begginers like myself :clappy many thanks :thumbsup

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Re: New sib problem

Post by Fishfinder » 18 May 2020, 14:24

Yes Chris, great information, once I’ve run the motor in I’ll be ready for take off :yay

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Re: New sib problem

Post by sonny1 » 18 May 2020, 14:43

@ChrisParish you should be a teacher Chris. that was an excellent answer clearly explained. Well done. this is what makes this forum great. clever people willing to give their time and knowledge to help others :thumbsup
Last edited by sonny1 on 18 May 2020, 14:44, edited 1 time in total.
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Re: New sib problem

Post by Sibfisher » 18 May 2020, 14:43

MadnessOfTheSeas wrote:
18 May 2020, 11:02
Great explanation for begginers like myself :clappy many thanks :thumbsup
I second that a bit confusing but I am sure it will all come together when I'm out in the boat :thumbsup

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Re: New sib problem

Post by RONHAS » 18 May 2020, 14:53

Not confused to me. In resume, if you cannot get on plane its better to slowdown avoiding the intermediate stage where the motor roars, eats a lot of fuel and the boat is only struggling with the waves 8-)

Mine has 3.60m and I will also use a 6HP outboard. With 2 persons on board plus gear will be almost impossible to get on plane, maybe with on person I'll get there, but with 2 (or even more) get on plane would be a miracle.
Being so.................let's enjoy and save fuel ohyeh

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