Current prop is a 3-blade 12X9 on a Universal 5411. Just doesn't have enough "oomph". Prop is clean, bottom is clean. Can't get more than 5 kts on calm water. 9 inch pitch seems a little flat. Does anybody out there have any success stories with something that has a little larger pitch? I don't need a folding or feathering prop (read: I don't want to spend the $$$). I'm looking for a specific size, not theory. Thanks for your help!!
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RonD
Prop Sizing
Steve Getting the correct prop is a matter of working the physical dimensions of your boat with the characteristics of your engine/transmission combination. Prop DIAMETER is established by the clearance between the shaft & hull. Too large, and you create excessive turbulence along the hull; too small, and you won't get the power. Prop PITCH is established by getting the proper match between your engine/transmission and the prop diameter/blade count/blade shape. This matches torque & RPM to the efficient movement of water to create the thrust. If the prop moves too fast there can be cavitation problems. Prop BLADE COUNT and WIDTH is a part of the trade-off between efficient power transfer vs drag. It affects the PITCH dimension. The idea is to match the optimum prop speed to the optimum engine torque range. You should get hull speed at the maximum recommended cruise RPM. Generally, it's best left to the experts to determine the correct match - 1st DIAMETER, 2nd the mix of PITCH & BLADE COUNT/WIDTH. Start with Catalina or the engine manufacturer; they can recommend the proper prop diameter. Tell them the engine type & transmission gear ratio to get a recommendation for the pitch (it's different for 2- vs 3-blade, and the blade width enters into this recommendation). Also, there may be a problem with your engine not being able to generate the proper torque at cruise RPM. Fuel starvation (e.g., clogged filters, pump problems, bad injectors) could be one of many possible causes. Before swapping props, make sure that your engine & transmission are working properly. Good Luck --Ron
Steve Getting the correct prop is a matter of working the physical dimensions of your boat with the characteristics of your engine/transmission combination. Prop DIAMETER is established by the clearance between the shaft & hull. Too large, and you create excessive turbulence along the hull; too small, and you won't get the power. Prop PITCH is established by getting the proper match between your engine/transmission and the prop diameter/blade count/blade shape. This matches torque & RPM to the efficient movement of water to create the thrust. If the prop moves too fast there can be cavitation problems. Prop BLADE COUNT and WIDTH is a part of the trade-off between efficient power transfer vs drag. It affects the PITCH dimension. The idea is to match the optimum prop speed to the optimum engine torque range. You should get hull speed at the maximum recommended cruise RPM. Generally, it's best left to the experts to determine the correct match - 1st DIAMETER, 2nd the mix of PITCH & BLADE COUNT/WIDTH. Start with Catalina or the engine manufacturer; they can recommend the proper prop diameter. Tell them the engine type & transmission gear ratio to get a recommendation for the pitch (it's different for 2- vs 3-blade, and the blade width enters into this recommendation). Also, there may be a problem with your engine not being able to generate the proper torque at cruise RPM. Fuel starvation (e.g., clogged filters, pump problems, bad injectors) could be one of many possible causes. Before swapping props, make sure that your engine & transmission are working properly. Good Luck --Ron
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Steve Franklin
I say again...
I don't want to appear unappreciative, but I've read the books and studied a bit of prop theory, so now I'm looking for very specific information based on experience. My brain is full, so PLEASE...no more theory!!! What SIZE prop??? I know lots of people are very intelligent re: what considerations must be given to chosing a prop, and have done a lot of experimenting (spent a lot of money) with different sizes. All I wanna do is "mooch" off some of that experience. I'll even trade info on my experience replacing the keel stub and engine logs for SPECIFIC SIZE information about props. Any more theory about props and I'll pull out what VERY little hair I have left. (Being genetically cursed with loosing the padding on top of my head can be a real pain, but that's what hats are for, I suppose.) Whew!!! So...does somebody...anybody...out there have a Catalina 30 with a Universal 5411, pushing a 3-bladed prop that they are happy (or at least happy enough) with. Thanks for your help and listening to the rantings of someone who is covered with epoxy and knee-deep in wood and fiberglass dust. Thank God I love to sail!!
I don't want to appear unappreciative, but I've read the books and studied a bit of prop theory, so now I'm looking for very specific information based on experience. My brain is full, so PLEASE...no more theory!!! What SIZE prop??? I know lots of people are very intelligent re: what considerations must be given to chosing a prop, and have done a lot of experimenting (spent a lot of money) with different sizes. All I wanna do is "mooch" off some of that experience. I'll even trade info on my experience replacing the keel stub and engine logs for SPECIFIC SIZE information about props. Any more theory about props and I'll pull out what VERY little hair I have left. (Being genetically cursed with loosing the padding on top of my head can be a real pain, but that's what hats are for, I suppose.) Whew!!! So...does somebody...anybody...out there have a Catalina 30 with a Universal 5411, pushing a 3-bladed prop that they are happy (or at least happy enough) with. Thanks for your help and listening to the rantings of someone who is covered with epoxy and knee-deep in wood and fiberglass dust. Thank God I love to sail!!
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RonD
OK ...
but you didn't provide anyone with sufficient information to give you an appropriate answer. Specifically, the transmission ratio. Different ratios mean different pitch, diameter being equal.
but you didn't provide anyone with sufficient information to give you an appropriate answer. Specifically, the transmission ratio. Different ratios mean different pitch, diameter being equal.
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Allen Schweitzer
Ron, Leave Steve Alone!
Ron, Let's not pick fights here, ok? Steve is asking a simple question & wants a simple answer. Really, Ron...How many different transmission ratio options do you think Catalina shipped with the C-30 powered by a 5411?? I'm guessing only one. Ron clearly requested "no theory" and you gave him a mouthful. I've been extremely frustrated in the past when I ask a question of an open forum (not this one, by the way) & people don't answer my question, they just use it as an opportunity to show others how knowledgeable they are. It sounds like you are VERY knowledgeable, but if you can't answer Steve's question, then let it go. Steve: I wish I could answer your question, but I've got a Yanmar. Someone should be able to get back to you, I'm sure. Allen Schweitzer s/v Drambuie C-30 Hull# 632
Ron, Let's not pick fights here, ok? Steve is asking a simple question & wants a simple answer. Really, Ron...How many different transmission ratio options do you think Catalina shipped with the C-30 powered by a 5411?? I'm guessing only one. Ron clearly requested "no theory" and you gave him a mouthful. I've been extremely frustrated in the past when I ask a question of an open forum (not this one, by the way) & people don't answer my question, they just use it as an opportunity to show others how knowledgeable they are. It sounds like you are VERY knowledgeable, but if you can't answer Steve's question, then let it go. Steve: I wish I could answer your question, but I've got a Yanmar. Someone should be able to get back to you, I'm sure. Allen Schweitzer s/v Drambuie C-30 Hull# 632
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RonD
Easy now
I don't know the C30 shipping options ... But the C320 (which I have) had at least two transmission ratios listed on the factory shipping forms. And, I wasn't "picking a fight" but attempting in good faith to make sure that Steve had the right info to make an informed decision. That's for him to use or ignore. That's what these BB's are about, isn't it?
I don't know the C30 shipping options ... But the C320 (which I have) had at least two transmission ratios listed on the factory shipping forms. And, I wasn't "picking a fight" but attempting in good faith to make sure that Steve had the right info to make an informed decision. That's for him to use or ignore. That's what these BB's are about, isn't it?
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Steve Franklin
Everybody shake hands and come out sailing...
Thanks for your assistance in saving me from more potential theory, Allen! I got nothing but theory on 3 out of 4 replies (so far) on 2 different forums. Good question, Ron. Hurth, 2:1. I just assumed that anyone with a C30/5411 would know that. One can't apply the theory until all the variables are supplied (no assumptions), though. To avoid the risk of running afoul of this forum, my e-mail is stevfran@earthlink.net. Didn't mean to engage in verbal combat. After all, us REAL boaters/sailors need to stick together, right?? Fair winds to all! But...I'm still searching for the answer...
Thanks for your assistance in saving me from more potential theory, Allen! I got nothing but theory on 3 out of 4 replies (so far) on 2 different forums. Good question, Ron. Hurth, 2:1. I just assumed that anyone with a C30/5411 would know that. One can't apply the theory until all the variables are supplied (no assumptions), though. To avoid the risk of running afoul of this forum, my e-mail is stevfran@earthlink.net. Didn't mean to engage in verbal combat. After all, us REAL boaters/sailors need to stick together, right?? Fair winds to all! But...I'm still searching for the answer...
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dr
try the sailnet.com cat30 list
try joining the cta 30 list at sailnet.com- at least temporarily- they may have an answer for you- or try the Catalina 30 association site- they have a tech manual. i'd like tohelp but i have an atomic 4
try joining the cta 30 list at sailnet.com- at least temporarily- they may have an answer for you- or try the Catalina 30 association site- they have a tech manual. i'd like tohelp but i have an atomic 4
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RDS
Engine
Sorry I don't have a specific prop but many of the Catalina 30's in my area have replaced their engines because of that problem. Not enough power.
Sorry I don't have a specific prop but many of the Catalina 30's in my area have replaced their engines because of that problem. Not enough power.
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Allen Schweitzer
I am SO SORRY!!
Ron, I just re-read my ealier post & I realized how "caustic" it sounded. I guess I really should switch to decaf. I didn't mean to come across the way I did. You have my apologies, Ron, and I promise I'll stay off the caffeine the next time I post, ok? --Allen
Ron, I just re-read my ealier post & I realized how "caustic" it sounded. I guess I really should switch to decaf. I didn't mean to come across the way I did. You have my apologies, Ron, and I promise I'll stay off the caffeine the next time I post, ok? --Allen
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Steve Franklin
And we have a winner!!!
Why I didn't just call David Graas at Catalina Yachts to begin with is a good question. Once again, he had the answer at his fingertips. But first, thanks to EVERYONE who provided information and education, whether practical or theoretical. According to David, a Catalina 30, Universal 5411, Hurth 2:1, takes a 12X10 3-blade prop. So I guess it's off with the prop and off to the prop shop. Thanks again, Ron, Allen, DR and RDS! Take care!
Why I didn't just call David Graas at Catalina Yachts to begin with is a good question. Once again, he had the answer at his fingertips. But first, thanks to EVERYONE who provided information and education, whether practical or theoretical. According to David, a Catalina 30, Universal 5411, Hurth 2:1, takes a 12X10 3-blade prop. So I guess it's off with the prop and off to the prop shop. Thanks again, Ron, Allen, DR and RDS! Take care!
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dr
not so fast
A guy on another list wrote: My C-30 with its 5411 came originally with a 12X12 solid prop which is still unused. I put on a 14X10 Martec, hoping for more "cut" in a seaway, with the 14 inch diameter, possible due to it's length. It will power to about 6 knots in calm seas, but won't go into four foot square waves in forty knots or more, when I have to reach off, usually with a working jib up. I tried to get the Universal 25 when I ordered my 1982 boat, but Catalina informed me that they didn't make custom boats. The 1983 model came with the larger engine, though. 1982 5411
A guy on another list wrote: My C-30 with its 5411 came originally with a 12X12 solid prop which is still unused. I put on a 14X10 Martec, hoping for more "cut" in a seaway, with the 14 inch diameter, possible due to it's length. It will power to about 6 knots in calm seas, but won't go into four foot square waves in forty knots or more, when I have to reach off, usually with a working jib up. I tried to get the Universal 25 when I ordered my 1982 boat, but Catalina informed me that they didn't make custom boats. The 1983 model came with the larger engine, though. 1982 5411
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Steve Franklin
Recount??
Was the 12X12 a 2-blade? I don't think Catalina used anything but 2-blade during that "era." From what I've gathered, a 5411 would have a hard time turning a 12x12 3-blade. When I called David Graas, I could hear him flipping through some pages and reading down a list until he got to C30 with a 5411. No hesitation with the 3-blade answer when he got to it. Was the Martec 14 a 2-blade? What other list was he on, dr. I'd like to take a look at some of the postings. Thanks! Steve
Was the 12X12 a 2-blade? I don't think Catalina used anything but 2-blade during that "era." From what I've gathered, a 5411 would have a hard time turning a 12x12 3-blade. When I called David Graas, I could hear him flipping through some pages and reading down a list until he got to C30 with a 5411. No hesitation with the 3-blade answer when he got to it. Was the Martec 14 a 2-blade? What other list was he on, dr. I'd like to take a look at some of the postings. Thanks! Steve
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dr
Cat30 list
Sailnet.com has a bunch of chat lists- there is one specifically for the Catalina 30. I threw the question out to the list and that was one of the replies. I guess a lot of guys think the 5411 was too small for the Cat30- no matter what prop you had.
Sailnet.com has a bunch of chat lists- there is one specifically for the Catalina 30. I threw the question out to the list and that was one of the replies. I guess a lot of guys think the 5411 was too small for the Cat30- no matter what prop you had.
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