AQ151B high revs low speed? help requested

AllanW

AllanW

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14 Jan 2010
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Gloucestershire\Boat\Colvic Watson 25.6\Cardiff
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Hi There,
This is my first post and I am also a first time boat owner. My retirement present :)
When I first got the boat (Sealine 195) last November she would run 20 knots at 4000 rpm. Last time out she was reving at just on 3000 rpm at 6.9 knots. It feels just like a slipping clutch on a car. I've changed the propeller, I read on this Forum that the centres can move, but there is no change. The boat is out of action until I can cure the problem. I don't want to cause any damage.
I would be grateful if someone could point me in the right direction for what else might cause this.
My apoligies if this has been covered elsewhere on the Forum, I tried a search but couldn't find anything.
Thank you
AllanW
 
Its stuck at hump speed, so its either lost power or too much drag, have you put a lot sof junk on board, do you trim the leg in and tabs down, do you send crew forward to get the bow down. An AQ151 is marginal for power on that boat so weight and trim are very important, you will also be surprised how dirty the bottom can get in just 6 months, was it antifouled with a type suitable for your cruising area.
 
Thank you for the replies. I'm on the River Severn. I didn't realise that the hull could get fouled so quick. I fitted the identical volvo prop as the new one that was fitted in Nov 09.
Chris_d : I run on my own (Billy no Mates:)) and have no excess of stuff on board. I do keep the trim tabs down and the leg trimmed in, after advice, as it helped the steering at slow speeds on the river.
If I push the throttle open at 5 knots she shoots up at the front and accelerates but the revs soar like blazes. That's why initially I thought it might be a slipping prop or clutch.
Looks like I'll have to have her lifted and get the hull done again ..... expensive this boating, isn't it :eek:
AllanW
 
AllanW said:
Thank you for the replies. I'm on the River Severn. I didn't realise that the hull could get fouled so quick. I fitted the identical volvo prop as the new one that was fitted in Nov 09.
Chris_d : I run on my own (Billy no Mates:)) and have no excess of stuff on board. I do keep the trim tabs down and the leg trimmed in, after advice, as it helped the steering at slow speeds on the river.
If I push the throttle open at 5 knots she shoots up at the front and accelerates but the revs soar like blazes. That's why initially I thought it might be a slipping prop or clutch.
Looks like I'll have to have her lifted and get the hull done again ..... expensive this boating, isn't it :eek:
AllanW
Click to expand...

If the bottom is quite dirty, check that the antifoul used is suitable for the area you cruise. Ours wasnt too bad when we had it lifted in march, we used an eroding antifoul and used the boat a lot so the bottom was almost always clean.

It neednt be expensive to pressure wash the bottom. It will only take an hour tops.

Im no expert on this but we always keep the trim tabs up (25ft boat) and only use them to compensate for cross winds.
 
CX54WEK said:
If the bottom is quite dirty, check that the antifoul used is suitable for the area you cruise. Ours wasnt too bad when we had it lifted in march, we used an eroding antifoul and used the boat a lot so the bottom was almost always clean.

It neednt be expensive to pressure wash the bottom. It will only take an hour tops.

Im no expert on this but we always keep the trim tabs up (25ft boat) and only use them to compensate for cross winds.
Click to expand...

Luckily the gentleman next to me has a pressure washer I can borrow. It's the lift out that's expensive up here. Still, needs must.
Below 7 knots she steers very badly without the tabs but she is only 19.5ft.
AllanW
 
AllanW said:
Luckily the gentleman next to me has a pressure washer I can borrow. It's the lift out that's expensive up here. Still, needs must.
Below 7 knots she steers very badly without the tabs but she is only 19.5ft.
AllanW
Click to expand...

Do you know anyone with a boat trailer?
 
CX54WEK said:
Im no expert on this but we always keep the trim tabs up (25ft boat) and only use them to compensate for cross winds.
Click to expand...

If you lower the tabs it can help a heavy or low powered boat get enough lift to start planing, once planing level them back out and use for cross wind triming as you say.
 
Anti foul only continues to work when water is removing a layer of the surface coat to expose fressh material underneath.On a fast boat you need a hard A/F other wise it will all get washed off PDQ,on a slow boat the A/F needs to wash off more easily.
If your fast boat with hard antifoul has not moved for six months the chemicals in the top layer will have gone without exposing new stuff underneath,the weed/slime creatures and barnycules take one look and think .....Yippee a new home.
 
problem found

AllanW said:
For a newbie that's why this Forum is so brilliant :) Thank you all for all your help and advice. I will try to come back in the not too distant future and let you know how things work out.
Kind Regards
AllanW
Click to expand...

Just wanted to update on my problem. It's the cone clutch :( boat is being lifted to carry out repairs next week, hopefully.
Thank you for all your help and advice.
Kind Regards
AllanW
 
AllanW said:
Just wanted to update on my problem. It's the cone clutch :( boat is being lifted to carry out repairs next week, hopefully.
Thank you for all your help and advice.
Kind Regards
AllanW
Click to expand...

Look on the brightside, at least you now know what it is...... Now you can get it sorted and enjoy your season.

Good luck,


Paul.
 
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