Hello to Martin,Tobias,Dave,Geoff,Kees and everybody
Finally I got my new prop last week and fitted it friday afternoon. I was told I would get a higher cruising speed at a lower rpm and less stress on the engine, with a bit more top speed, although that wasn't too important to me. I was fairly sceptical as you can imagine.
The boat went back into the water on saturday morning, and the first thing I noticed was a much better bite when reversing . After 10 minutes, I reached the ocean and put the revs up to 2000 and got 13.7 knots. Previously only got 11 knots. Up to 2200revs I got 15.7 knots and top speed she made 24.5knots against 23.6 previously. The engine still over revs by 150 so she is doing 2850 instead of 2700, But I think I will leave it as it is. According to Yanmar no engine damage will occur. I am more than happy with that.
take care Harold
-- Edited by Harold Timmer on Monday 30th of July 2012 09:38:08 AM
Those figures are great. I would love to get even close to them. I notice you have a full skeg too which is supposed to slow these boats down a bit according to eveyone. Looking at the prop in pic 4 it doesn't seem to have a big area compared to some othe props I have seen, is it a new design and what are the specs, as long as it isn't a secret.
Hope you get to enjoy many hours afloat now you are back on the water.
The prop people are in Brisbane and this design is the result of 35 years of experience. Those prop's are cast in China and are fine tuned in Brisbane.22.5x30 is this prop.I agree with you that it doesn't have lot of blade area however the blades are so curved that it is hard to tell. All I have to do is use the the boat as you say but my poor wife gets seasick. Whats you're remedy?
nice pop and figures.....there is much to win with the right propeller ....I have a 27x 27 i will try to swing this month, i allready know its to big but i shall test the limits and se what happend...
Hi Martin,geoff and Tobias Thank you for you're advice Geoff see where I can buy it here. We are allright here but business is very slow. Tobias, I was always told that you need 10% of the diameter of the prop in between the tip of the prop and the bottom. What do you think. You're boat is looking good. Do you think you can finish it before the end of the summer?
Thats a nice top speed you are getting there now Harold and as Geoff says, to improve on that would be costly for very little extra if anything. Besides, I expect you can cruise around 18 knots and that covers ground well!
I don't know what sea conditions you encounter over there but there are'nt many occasions here when we can really cruise comfortably at much more than 20 knots. Sure 'Sorcerer' is capable....she is a Lochin after all and as you know has done 30.5 knots tops and probably would through anything, but my body would'nt!!
Tobias thats a decent prop you are trying.......very interested to see how things go, keep us posted please.
I knew i have being told all the recommend limits to hull ... i just have some test that i will do, maybe it will do some happiness or another propeller adjust... a teacher told me about a thing he developed when he was a ship constructor to raise the speed of water up of the propeller you will get lower cavitation , he create a few small triangles on the keel that raise the flow of water upper propeller top and than reduce the cavitation.. any one heard about it ? i will practise it..
maybe it will be another year of dock crab fishing daughters .....
Nice prop, nice speed, think you are close to max. good calculation from your supplier.
Is it a Hung Shen high skew prop with close to 100 % blade area ?
lucky me or Chantal never got seasick on board, but Chantal can sometimes become seasick after a ruff fishing day at sea, when stepping a shore ? land sick ??? also at home laying in bed, she sometimes feels as if she is still at sea ??
Pumped a lot of seawater in Tommie last week.
two years ago i replaced the zinc anodes in the raw water cooling system with imitation anodes, as the original bronze / zinc Iveco anodes had a very long delivery time. it appears now that the bold part of this imitation anodes is not made from bronze but from copper plated ordinary iron. One rusted away and was pressed out. The raw water pump pressed a lot of seawater through a nice 19 mm hole into the bilge. when the bilge alarm went off, there was 500 ltr. seawater under the engine.
Yes Kees it is a Hung Shen prop. You know your prop's don't you. Went out on sunday and the boat went so well wish I could say that about the fishing.
Lucky you got a bilge alarm. It is amazing how quickly it fills up. It has happened to me too after I removed some pipes from the engine for maintenance.I was convinced that I had done up all the hose clamps except for one. It took me an afternoon to get rid of the salt, and a dent in my ego.
Above 14 kn. we always had a small vibration and i blamed the prop, so lifted Tommie out of the water. The prop carefully balanced and the prop shaft alignment checked and rechecked when in the water. At the testrun still vibrations and a sound like the rotors of a helicopter after the stern. As i become nervous from vibrations, ( sooner or later cracks appear or something breaks ) so i decided to lift her out of the water again and removed the propshaft complete with prop and let it balance as a unit at a company where they balance fan and turbine impellors. They balanced prop and shaft to less then 0,8 gram. Back in the water, still the same vibrations. If it was not the prop, shaft or alignment there must be something else causing this vibrations, so we lifted her out of the water again. When we bought her, there was a 9 cm. thick wooden block between the P strut and the hull. In fact the strut was to short and somebody solved the problem with a wooden block in place of buying a longer strut. The idea came that the propellor tips where in the shadow of this wooden block, or the block caused turbulence in front of the prop, or the strut was simply to weak. Out of other options, i removed the strut and block and made a V strut from 316 l stainless steel. Back in the water finally all vibrations gone, so we can boating with peace of mind.
Good job you have access to all the engineering stuff and are able to get Tommie in and out of the water. Where I operate from it would be a real pain in the a*** and I would have to do it alongside a pier between tides.
Glad you have eventually sorted your vibration, I bet it gives you a lot of satisfaction and peace of mind now.
I have been away repairing boats in Sydney hence no posts lately.
Kees, I admire your determination to get things right. Good that you found the problem, however, did you earth the stainless steel bracket to your rudder and engine? Don't mean to be a smart alec, but, I didn't and it cost me a lot of grief.
Are you going to take the boat out of the water for winter?
In the workshop we can make almost everything but lifting her out of the water and back in they do in the marina and costs out and in euro 300,- so I spent more on cranehire then on fuel this year.
Halfway outside Tommie's hull is a big copperplate, from there a wire is connected with a carbon brush to the propshaft, from there it goes to the ruddershaft, al further zinc anodes and then to negative of the batteries. The V strut is not connected in this circuit as people in the marina told me not to do as it's electrical isolated. I think they can be right, I once put a new zinc anode on the hull, but forgot to connect the wire. After one year the anode was as new, when the wire was connected the anode was almost gone one year later.Tommie stay's always in the water in wintertime, as then cod comes close to shore following the scrimps and it's the only bigger fish we can catch overhere in reasonable numbers. When tommie comes out the water this spring, first thing to check is the V strut for pitting off course.
last week a friend of me heard the bleeper alarm of his dept sounder and thought the '' thing'' had an error or was broken. A few secounds later the '''thing'' proved to work fine. result : two bended props, two bended ruddershafts and one bended propshaft.
