Wahoo you will notice a huge difference lifting them the 30 odd mill. Youl pick up about another 500 rpm so youl have to go the a 15p prop or a custom solas. Ian (finding time) got 1/2 inch shaved off 15p props and rated that move. My next move was solas props but never got around to it. From memory Fly tried solas and went back to a 15p factory prop. Lift them 2 holes I say whats the spacing between 2 holes measure?
Just saw pic with tape measure I missed that one. Maybe try 2 holes and she cavitates too much go back down a hole. Youl be amazed at the difference 😆
I thought Finding Time gave up on trying to make a 18 kc go quick and just kept a big bag of pot on board. Slowest boat in the world.
nil carborundum illegitimi
Thanks guys, I lifted it 2 holes last night so its now 70mm above the hull. Took it out this morning and its made a huge difference. Gets out of the hole even easier than before and it doesnt fall off the plane as I slow down anymore. It was rough as today but it didn't cavitate at all so Ill give the 15p props a go now. With the engines lifted Im getting 35kph at 4900/5000rpm and a WOT of 50km at 6200rpm. Im very keen to give the 15p a go and get the revs down a bit. The boat seemed to ride best about 35/40kmh in the rough water, it got a little smoother when I tried pushing it a bit harder but it was starting to get some serious air off the swells!
Thanks for the advice, I'll let you know how I get on with the new props.
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Here are a couple of pics of how they are sitting now. The splash plate on thr leg is about level with the bottom of the pod. I definitely need to make up some bigger splash guards like I saw in one of your other posts Dean1. Now that they are sitting higher they are throwing wash all over the place at slow speed.
Its amazing the amount of difference that extra 30mm made! Thanks guys
Its amazing the amount of difference that extra 30mm made! Thanks guys[/QUOTE]
That's what my missus says...
fruit salad is the new Bacon
Thats good it would be alot lighter in the steering now and it will feel alot more flighty. Youl get better fuel economy as well.
I got 23 kts or 43klms at 4800rpm. 28kts at 5500rpm with the 15k props. Nice looking kc mate. I love the black mercs 👍
Thanks for the figures Dean, gives me something to aim for. With the props that Ian has shaved, do you mean the diameter as in he went from 13.5 x 15p to a 13 x 15?
Yes mate pretty much. Im not sure on the diameter of a 15k yammy prop but im pretty sure he took a 1/2 inch off each blade. He lost some top end speed but the motors worked alot easier and got out of the hole quicker. Flick him a message. A guy at maroochydore used to do it but hes no longer there. Keep us updated. CheersOriginally Posted by wahoofishingcrew
Might take a while to get an answer, he's off Tahr hunting in the NZ southern alps at present.
nil carborundum illegitimi
G'day guys, finally had a chance to give the new props a decent test. Weather has been shocking up here so haven't been able to get out much lately.
I got a set of 13.5 x 15p solas alloy props. The first run I did with them was loaded more than I normally run, 4 blokes and gear on board plus the centre esky full of bait, ice, fish and full of fuel. The poor little KC struggled, it was only pulling 4400rpm WOT and 38kmh. The following day I put the old 13.75 x 13p props back on and the same load again and it ran almost exactly as it would with a normal load, cruise 40km at 5000rpm and WOT pulled 6000rpm. Have to agree with what fromeo said earlier about the 13p props being the go if running alot of weight all the time. They pulled it out of the hole no problem where as the 15ps were really struggling.
Yesterday I put the 15p's on again and ran a normal load, full of fuel, 2 people and gear. The props performed really well cruising at 42kmh at 4400rpm, 50km at 4800. WOT pulled 5700/5800rpm however the speed only increased to 52kmh. How is it that an extra 900ish rpm doesn't achieve any more speed?
Cruising on 50kmh, it feels like the boat is being thrown from the water instead of just the nose coming out at 40kmh. I passed a KC2100 yesteday and the swell was about 1m in quite a sharp chop and noticed the entire boat was coming out of the water with just the legs of the outboards staying in. Is this a typical KC thing, or is it better to back off slightly and keep some boat in the water?
As far as the props go, I think I'll keep the 13's in the shed and put them on when I plan to take a bigger load than normal and the rest of the time I'll run the 15's. Anyone have any ideas why I'm not picking up anymore speed with the extra rpm?
Thanks for the help everyone. Dean cheers for the PM too, I will give you a call about the spinouts one weekend soon.
Cheers
John
Also a quick question about fitting the newer 1900 pods to the older hull. Has anyone actually done this? I have read alot of posts where it said it is possible however didn't see any where anyone had actually done it. Do these new pods suit a standard shaft motor or are they for the extra long shaft too?
I have no experience with Cats at all, but if at 50k's per hr it's starting to feel the way you said it is then you wouldn't want too much more speed would you?
Darren
I owned a 5.2 kc with f60's for a while. They are by nature a flighty boat, being 17f long and light. I found pushing the boat at 48-50km was its best ride on your average 10-15k day with a bit of chop. Anything less and the nose starts to fall down ever so slightly into the face of next wave. If you push it harder the nose is always going upwards and softens the ride.
The issue was running at above 50km/h with twin 60's puts motors in self destruct range for rpm's.
Dontget get me wrong the ride is still fantastic, but the hull isn't performing at its best.
all depends how far offshore you go to how fast you need to run too.
Sounds like the 60's just run out of puff. Probably need to go up in hp to get more speed out of her hey. Would this be correct?
Darren
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