I have a 1988 Catalina 30 with a M25 Universal diesel and the standard 13 x 12 2 blade prop the boat came with. In calm conditions at about 2500 RPM (no wind or tide) the boat goes about 5 knots plus or minus a very little bit. Both the boats bottom and prop are cleaned every month by a professional service. Some tell me that their Catalina 30's with the same power perform much better, others say that 5 knots sounds about right. Before I pull the prop and send it out to have it checked I thought I'd ask this question to the forum.
Motoring Speed?
- Thread starter jeffreckson
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My '91 Cat with an M25xp and 3 blade wheel does 6 knots (plus a little at times). So, your 5 knots does sound about right.
Merry Christmas.
Merry Christmas.
Mine depends on wind, currents, and waves. I am somewhere between 4.5 and 5.5 knots.
The Catalina 34 and 36 have the same engine in them but motor a bit faster than mine. My uncle has a Catalina 34 (1988) and it has the same engine but he gets .5 knots more than me. It is because he has a bigger prop on it.
The boat has plenty of engine for a 30 foot boat but not enough room for a bigger prop and that is why we don't get much more than 5 knots.
The Catalina 34 and 36 have the same engine in them but motor a bit faster than mine. My uncle has a Catalina 34 (1988) and it has the same engine but he gets .5 knots more than me. It is because he has a bigger prop on it.
The boat has plenty of engine for a 30 foot boat but not enough room for a bigger prop and that is why we don't get much more than 5 knots.
My 89 C30 with a 3 blade prop will motor at 5.5+ knots @ 2500 RPM with a slimy bottom. A clean bottom gives me at additional 1/2 knot.
Are all of these claims subjective, knotmeter numbers (calibrated?) or tested with a GPS?? Are they tested 1/2 mile one way and 1/2 mile the other way and averaged to account for current (OK, I am getting a little anal now...I haven't done this either..
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B.O. - the reason your C-34 uncle goes faster is not the prop...his boat has a higher hull speed due to increased LWL (waterline length) - There are other props available for the C-30 that have extended hubs on them to increase tip clearance if you really want one. I do not know if that will make you go any faster.
I have an Atomic 4, with a 10"x7.4 pitch 3-blade Indigo prop, so we are comparing apples to oranges, however, our LWL's are the same, so I'll throw mine in anyway.
WOT, 2150RPM, clean bottom & prop I can get 5.7 (GPS speed, & knotmeter calibrated) - I cruise at about 1,800 RPM (when the bottom is clean) and do about 5.0-5.1. Right now my WOT speed is 5.4 because I haven't cleaned the bottom since July, & my cruise speed is down to about 4.5-4.6.
)B.O. - the reason your C-34 uncle goes faster is not the prop...his boat has a higher hull speed due to increased LWL (waterline length) - There are other props available for the C-30 that have extended hubs on them to increase tip clearance if you really want one. I do not know if that will make you go any faster.
I have an Atomic 4, with a 10"x7.4 pitch 3-blade Indigo prop, so we are comparing apples to oranges, however, our LWL's are the same, so I'll throw mine in anyway.
WOT, 2150RPM, clean bottom & prop I can get 5.7 (GPS speed, & knotmeter calibrated) - I cruise at about 1,800 RPM (when the bottom is clean) and do about 5.0-5.1. Right now my WOT speed is 5.4 because I haven't cleaned the bottom since July, & my cruise speed is down to about 4.5-4.6.
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We operate our 1984 M-25 @ 2300rpm and get 5.0 - 5.5 kts from the GPS in flat water, using the original sized 2 blade. I could definitely feel the speed difference at the end of the year; much slower with a fouled hull and prop.
Rob
Rob
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