props & rudders

snowstorm

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i have a couple questions. after many years with outboards last year i bought my first imboard. a 28' ellis flybridge. it was a bit of a learning curve. it has a fiberglass rudder if iswap it with a stainless one will it help? backing into the slip? it has a right hand wheel will swapping to a left help? helm is on the right. power is a volvo tamd41p hs1 200hp. shaft size 1.5" prop 18x16 rh. top speed 15kt @3950. i have been told the volvo trans can be run either direction that true? it would seem to me it would be better to have the prop turn the same direction as the engine or dose it matter? also was told motor should turn 3800rpm if so would one inch of pitich do it? last question anybody have a lh wheel laying around?
 

F/V First Team

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What kind of transmission do you have on the back of your Volvo? TwinDisc or ZF really don't care if they're spinning left or right on the output shaft. Other transmissions aren't always 100% duty cycle. Sometimes they are only around 80% in a particular direction.

Switching to a stainless rudder might help you some speed wise, but backing down it's a toss up. Depends really on how big your rudder is, because when backing down your keel is acting more as a rudder than your actual rudder is, you need it big enough so it can cleave and grip the water. Try goosing the throttle some to get steerage. Trial and error and all that jazz. You could always toss out some buoys or the like and practice navigating like that so you aren't near other boats or obstacles that might damage your vessel. I would try that before swapping propellers.

Rule of thumb is one inch of pitch for 100 rpms. Since you're over revving adding an inch of pitch should take you down to 3850 give or take. Adding cup might do this too, it's entirely up to you as to what you decide to try.
 

snowstorm

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What kind of transmission do you have on the back of your Volvo? TwinDisc or ZF really don't care if they're spinning left or right on the output shaft. Other transmissions aren't always 100% duty cycle. Sometimes they are only around 80% in a particular direction.

Switching to a stainless rudder might help you some speed wise, but backing down it's a toss up. Depends really on how big your rudder is, because when backing down your keel is acting more as a rudder than your actual rudder is, you need it big enough so it can cleave and grip the water. Try goosing the throttle some to get steerage. Trial and error and all that jazz. You could always toss out some buoys or the like and practice navigating like that so you aren't near other boats or obstacles that might damage your vessel. I would try that before swapping propellers.

Rule of thumb is one inch of pitch for 100 rpms. Since you're over revving adding an inch of pitch should take you down to 3850 give or take. Adding cup might do this too, it's entirely up to you as to what you decide to try.
its a volvo trans. i belive the hs1 is the model. so you think the rpm should come down a bit then? betwen trucks and equipment i have 13 diesel motors so i am not new to diesel but it the first volvo. around the dock this thing can be a pain. by the end of the season it wasnt so bad. didnt help any being down by the old bridge in belfast
 

Frigate

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The boat I had before this one was a 28' with a Volvo TAMD 41 and a Volvo transmission. 3950 RPMs is where you want to be not 3800 RPMs.

Backing in takes a little practice and do everything at slow speed. A little throttle once in a while when you need it but most of the time it is back then kick it ahead a little and then back some more. I have gone over the years from a 22' Downeast to a 28' Downeast to a 38' Downeast. The 22' I never had to use throttle to dock. the 28' I used the throttle a little to dock. The 38' I am on the throttle alot. However at times I am backing in with a 5 knot current.
 

snowstorm

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seahorse blue hull white above. i went down to ellis and they showed me the build sheet on it. was built in 84 with a bmw motor. repowered with the volvo in 96
 

snowstorm

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it wont be back in the water for a couple months. its resting behind the garage rite now
 

captainlarry84

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With single screw boats it is better that the wheel spins the opposite rotation of the motor. I doing so run speed the boat will not tork to into to one side.

Changing the rudder will do nothing that you will feel or notice.

One inch of pitch on a 1:5 transmission will increase RPMs by 200 turns
 

snowstorm

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i see you have daves race boat listed on your website. so i take it he hasnt had any luck selling it. ya i know him
 

steveinak

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its a volvo trans. i belive the hs1 is the model. so you think the rpm should come down a bit then? betwen trucks and equipment i have 13 diesel motors so i am not new to diesel but it the first volvo. around the dock this thing can be a pain. by the end of the season it wasnt so bad. didnt help any being down by the old bridge in belfast
Be aware that that trans has a shifting cone in it just like the volvo outdrives have in them and after awhile the cone tends to glaze, you'll know when its glazed because when you shift into gear nothing will happen unless you give it some additional rpms and it will shift into gear with a bang, the fix is to have the cone deglazed. 3950 is good for that engine at WOT its right where the book says it should be. Those engines are real touchy about being overpropped usually they don't last too long if overpropped or overheated to many times.
My last boat had a 41P in it with a duoprop outdrive, sold it with 5200 hours on the engine and it was still running strong. It turned up 3950 at WOT and i ran it at 33-3400 rpm at cruise speed(aprox 17knots) 2 things i did to it was to install a pyrometer and it also had a Racor crankvent instead of the tiny little breather tube that volvo puts on them.

Racor crankvent
DEC racor crankvent.jpg

probe for pyro
DEC pyro.jpg

engine just before sale. I replaced the volvo air filer with a K&N filter. You can also see the hoses on the crankvent coming from the valve cover and the other hose going to the K&N air filter, the blue hose on the crankvent went back into the oil pan.
DEC engine.jpg

DEC racor crankvent.jpg

DEC pyro.jpg

DEC engine.jpg
 
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snowstorm

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looking in the parts book i dont see a cone clutch. i do see 16 steel and 14 fiber discs. i have never been inside a boat trans but i have in equipment it looks like the same idear as the reverser on a case hoe. except the case went faster in reverse. ...........i can see the point of having the prop not turn the same as the motor but a lot do it . would like to hear what everyone thinks about it...........the rudder i may change to stainless. the glaas one has been there since 1984. the new style stainless is a bit different in shape.........thanks guys for all your help
 

BillD

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its a volvo trans. i belive the hs1 is the model. so you think the rpm should come down a bit then? betwen trucks and equipment i have 13 diesel motors so i am not new to diesel but it the first volvo. around the dock this thing can be a pain. by the end of the season it wasnt so bad. didnt help any being down by the old bridge in belfast
You "could" consider a bow or stern thruster if docking is a major issue.

Or go through another season of practice and get better @ it!
 
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