Performance Problems Crownline 242 - Any Suggestions

[hlb]

it wont be going through the same filter's if he change's them first!
and yes you would have to bleed the system.if it run's ok on clean fuel you will no were the problem lie's
their is alot of advise on here you chose were you want to start from!

If he changes the filters, it will run ok as which fuel is used, at least for a hundred miles or so. The point I made was to examine them, maybe put them back on if everything is OK.

Bugs not that hard to deal with, especially if it can be caught soon.

The clue is, that the engine revs keep changing.

Add this to eight months of growth on the bottom and it's not surprising that it's slowed down.

 

[dominic221]

Performance Problems Crownline 242 - Any Suggestions Reply to Thread:/Update

Hi All, thanks for all the advise.

I had someone dive down and check under the boat at the weekend. Could not find any part numbers on the prop. Only marking was VOLVO PENTA stamped behind one of the blades. So Im not sure no how to determine what pitch they would be. They do look to be the original props, each has four blades. There was a slight nick on one of the blades, but other than that in reasonable shape.

Build up and growth, there was none between bow and midship, but a little from midship to stern. Had this cleaned off and he also cleaned the prob of build up too, again not much there in comparison to other on the marina.

Had an expert take it out today and he cant see any problems, engine is running fine, turbo working, it got to the plane fine for him. The only thing he suggested was some indicators for the trim tabs as they may not be working, and to be honest I only use them when I have been on the plane to level the list on the boat.

Hope to get out on it in the next couple of days to see if the cleaning of the prop and the use of the trim tabs has made a difference that I would notice.

I'll keep you all posted, thanks again for all your help.

 

[CX54WEK]

Dont know if this is any help but we have a Sealine S23 (25ft) with a KAD32 and duoprops. She normally jumps onto the plane if you give her some stick/lever but when planing down the humber last week she took some getting up and over. We think it must have been the heavy loads on the way down to Hull, beer in the bow locker, full tanks etc as on the way back she was again jumping onto the plane pretty quickly. She was only relaunched a few weeks ago so has a clean bottom, clean undinged props and clean fuel.

It just shows how a little extra weight can make all of the difference.

She revs all the way to 4000rpm easily but we always cruise at about 3500rpm.

 

[MapisM]

The only thing he suggested was some indicators for the trim tabs as they may not be working, and to be honest I only use them when I have been on the plane to level the list on the boat.

What did he mean by "may not be working"? If he tried the boat, he should have seen if they actually worked or not.
Anyway, try keeping them (and also the outdrive) all the way down while accelerating, and then raise them fully as soon as the boat gets up. Then raise also the outdrive, but not fully, just about at neutral position.
You should not need tabs while cruising in normal conditions (normal and well distributed load, no crosswind, no head sea): they add drag and reduce speed. If after raising them completely you need to correct some listing that isn't due to improper boat load, just lower as little as possible only the one on the listing side.

 

[dominic221]

MapisM
I dont have any trib tab indicators so he couldn't check if they were fully down, (or up I suppose). I'm going to get my diver buddy back again see if he can check this out and also going to investogate if I can get a indicator panel for the tabs.

CX54WEK
Do you know how much you boat weighs? I check out what Chris_d mentioned on weight and mine weighs 2400kgs dry, so with fuel, water and gear the 170hp engine is probably the absolute minimum that this size boat should have.

All
Does anyone know where I could find manufacturers sea test results? eg: when new with this set up what should the boat achieve?

 

[MapisM]

I dont have any trib tab indicators

Whoops, sorry, I understood that "they" were the indicators, and he was suggesting to replace them.
Anyway, it shouldn't be difficult to check if they (the tabs ) are working - just do that while the boat is moored.

 

[landlockedpirate]

Your boat will weigh close to 3500kg in cruising trim, with full tanks, 4 people on board, tender and the usual cruising 'junk' we all acumulate, it could be nearer 4000kg. Although the KAD is a great engine with loads of torque it has only got 170hp.

I think that the engine is simply struggling to do what its being asked, it probably never gets fully on the plane, the engine will never pull full revs.

Its a known problem with sub 30ft sportscruisers from around the year 2000 onwards. The market demanded diesel power and the only option available to builders was the KAD32. They put this engine into boats that were designed for a minimum 220hp V8 Petrols and some of them struggled. It worked OK in a few boats (Sealines S23 was a bit lighter and narrower and performed really well with the oil burner) but others were well underpowered (I sea trialled a new Four Winns 268 that barely got on the plane).

If you have checked everything is working as per spec than you may need to adjust your cruising to suit the boat. Put all the weight you can up front, only fill the tanks half full, keep the tabs fully down and the hull clean. A different set of props may help as others have said, but if it gets on the plane easier, you will lose top end speed.

 

[CX54WEK]

MapisM
I dont have any trib tab indicators so he couldn't check if they were fully down, (or up I suppose). I'm going to get my diver buddy back again see if he can check this out and also going to investogate if I can get a indicator panel for the tabs.

CX54WEK
Do you know how much you boat weighs? I check out what Chris_d mentioned on weight and mine weighs 2400kgs dry, so with fuel, water and gear the 170hp engine is probably the absolute minimum that this size boat should have.

All
Does anyone know where I could find manufacturers sea test results? eg: when new with this set up what should the boat achieve?

Ours weighs 2400kg dry. So add to that full fuel tank at 50 gallons, full water tank at 25 gallons, beer (well we where away for the week!!!) plus all of the **** aboard (on that nore the holding tank was also half full) i would say we where easily pushing 3500kg or even more. It is no great suprise she was struggling to get onto the plane properly.

We have always felt that the KAD32 at 170hp may be a little underpowered for the boat, but it does give the right balance of economy and performance for us using her mostly on the rivers. On the odd occasion we get to use her properly, like last week, she performs enough to keep us happy. If we kept the boat at sea it would be a different matter and we would look to a bigger boat with more power.

 

[dominic221]

Guys
I thought I would just let you all know; that the boat is now performing as i would have always expected. Jumps straight on plane; speed even with a bit of chop; 28knots no issue and will still give a little more.
Cruises on plane nicely at speeds between 14-20knots. Its like a anchor has been lifted from my shoulders.

The fix - Well gave a little clean, and fresh anti-foul; so may have gained a little there. Biggest and most expensive was a new set of props. Those originally on there we A6's as someone did say. I couldnt find any data realting to what to new size to go with, but based on feed back on here and the boatyard, I went for a pair of A4's; I think I might have gotton away with A5's but I'm not complaining at all!

Sorry its taken me so long to post back; I have been too busy enjoying it!

Thanks to everyone for your help and advice.