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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

outboards, blah!!!

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lancej
1st Mate

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81 Posts

Initially Posted - 08/18/2003 : 07:29:03

Hey guys, more help needed! Went out yesterday, good sailing but had a problem getting out of the dock. There was a 10-12 knot offshore breeze (odd for Buffalo) pushing my C25 effectivly back into my slip. Try as my little outboard might, I just couldn't seem to back out with enough control or force to get the boat pointed correctly to motor out to the lake. I am using a (don't laugh) 1975 mercury 4.5 HP lonshaft. It runs wonderfully, am I just underpowered? Reverse just doesn't seem to want to move the boat. In my opinion, the whole exhaust thru the prop idea, with the force of the exhaust countering the prop rotation is a bad one, though I understand why they do this. I am thinking of an upgrade to the new Nissan 8 HP 4 stroke with electric start and charging system. I guess the question is: do you think this will be a big help? It wasn't a huge problem, but it took three tries to get my (still unnamed) C25 out of her slip, and my wife was really starting to question my abilities. Can't have crew problems like that!! Thanks guys!

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n/a
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163 Posts

Response Posted - 08/18/2003 : 08:11:15

I think you already know the answer; 4.5 hp just doesn't have enough thrust in reverse to power you out against a stiff breeze. If you can 180 the motror, you may have better luck, but I think you may want to upgrade to an 8 or 9.9 hp motor.

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 08/18/2003 : 09:32:54

Hi Lance... The reason thru-prop exhaust is a problem is that in reverse, the exhaust gets sucked back into the prop, causing cavitation. Honda has a separate exhaust vent for reverse, just for that reason. But one way or another, your motor isn't up to pushing or pulling 5500+ lbs the way you should be able to on the Great Lakes.

If you get the Nissan or any other 8+ hp 4-stroke, you may need to upgrade your bracket to take the weight and the thrust. There are lots of recent threads on that... Also, get a "power prop" (the lowest pitch and largest diameter it will take). That makes a huge difference starting, stopping, and backing. That's the primary component of the High Thrust and Power Thrust options on Yamaha and Honda. If Nissan offers an extra-long shaft (25" or more), get that too. (I seem to recall they don't--an argument for Honda and Yamaha.)

Happy shopping... <img src=icon_smile_shock.gif border=0 align=middle>

Dave Bristle - 1985 C-25 #5032 SR-FK-Dinette-Honda "Passage" in SW CT

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 08/18/2003 : 10:08:06

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>The reason thru-prop exhaust is a problem is that in reverse, the exhaust gets sucked back into the prop, causing cavitation. Honda has a separate exhaust vent for reverse, just for that reason.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

My 1995 8hp Mercury has a separate exhaust vent for reverse also.

<img src="http://www.catalina25-250.org/c25sm.gif" border=0>Don Lucier<img src="http://www.catalina25-250.org/c25sm.gif" border=0>
<img src="http://im1.shutterfly.com/procserv/47b2d904b3127cce9f7cd9ffdf1d0000003010" border=0>
North Star SR/FK

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ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 08/18/2003 : 10:16:41

Along with the exhaust problem, most propellers are optimized for delivering thrust in the forward direction. Reverse thrust is already compromised from the get-go.

IMHO... agreeing with other posts...

You need an 8hp model for operating in 'tough' conditions. The newer high-thrust, extra-long shaft models are really the way to go.

If you have the original "couple pieces of aluminum and a prayer" engine mount, that will need to be upgraded too.

Currently maintaining two holes in the water...'77 Venture 23 and new to the family,
'78 Catalina 25

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jsummerfield
1st Mate

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USA
96 Posts

Response Posted - 08/18/2003 : 10:20:37

I do not share your specific problem. Buy my 1996 Mercury 9.9 four-stroke. It will solve your thrust problem when it runs. Instead of replacing it, I will use the money to have a tow-boat take me in and out of Galveston Bay.

My Mercury can be hard to start, the throttle is not precise, it pulses when running, cannot be depended upon at idle and most important tends to stall when needed most - slowing down approaching or during the turn into the slip.

John
C25 3973 FK/SR
"Texas Tango"

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lancej
1st Mate

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81 Posts

Response Posted - 08/18/2003 : 10:29:43

thanks guys! I was leaning towards the Nissan for a few reasons: 1) cost, at $700 or so less than the Honda... 2)Weight, at 81 lbs. for the 2004 8/9.8, it is only 10 lbs heavier than my current "black beauty" mercury... 3)Nissan is a world class engineering company (not so much for OMC.) I think the extra long shaft's advantages can be somewhat canceled by the electric start, but I am intriuged about the Honda exhaust being re-routed in reverse, but I still doubt that to be worth $700. Anyway this all refers back to an earlier post of mine that an excellent hull and rig like the C25 deserves a proper inboard diesel.

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Bryan Beamer
Master Marine Consultant

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USA
1038 Posts

Response Posted - 08/18/2003 : 11:58:11

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>I think the extra long shaft's advantages can be somewhat canceled by the electric start <hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

<img src=icon_smile_question.gif border=0 align=middle><img src=icon_smile_question.gif border=0 align=middle>

Bryan Beamer
<img src="http://im1.shutterfly.com/procserv/47b3d935b3127cce8ab87c3b48020000000010" border=0>
Daylight Again
C250wk #495
2003 National Champion

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lancej
1st Mate

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81 Posts

Response Posted - 08/18/2003 : 12:16:38

meaning one of the advantages of a 25" shaft on boat with as much freeboard as a C25 is the realative position of the powerhead of the motor when pull starting, as my lonshaft (20") motor is sort of a pain to lean over the transom to grab the cord. Beyond that I cannot really think of a great advantage of a 25" shaft for the C25. One fella in my marina actually uses a short shaft with electric start on a hunter 25, with a removable shaft connecting the rudder and motor.

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 08/18/2003 : 12:18:58

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
...an excellent hull and rig like the C25 deserves a proper inboard diesel.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>
Lance: One reason I chose and expect to stay with the C-25 (no 5-foot-itis here, yet) is to be able to drive it with an outboard. If I were a serious ocean cruiser, I'd go 36'+ with a diesel. Outboard's broken? Take it off and fix it. Not strong enough? Take it off and replace it. I admit that at 108 lbs., mine isn't that easy to "take off"... But get an 8 hp 4-stroke on your boat, and you'll be thinking differently about auxilary power. <img src=icon_smile_approve.gif border=0 align=middle>

I'm curious--how does electric start compensate for shaft length? The reason longer is better has to do with the way a 25' boat pitches in any sizable seas or even boat wakes.

BTW, I know the Nissan 9.9 4-stroke is the same engine as the Merc 9.9, both made by Tohatsu. I don't know about the smaller Nissan 4-strokes. Also, with electric start, alternator, and long shaft, the Nissan 8 will be heavier than the nominal weight--I'm gueesing by 10-15 lbs. I won't argue in favor of OMC, especially not that Bombardier apparently wants to get rid of them...<img src=icon_smile_dead.gif border=0 align=middle>

Dave Bristle - 1985 C-25 #5032 SR-FK-Dinette-Honda "Passage" in SW CT

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n/a
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163 Posts

Response Posted - 08/18/2003 : 12:22:18

The advantage of the xl shaft will become self-evident in any kind of seaway, especially a chop where the wavecrests are square and close together. You'll have much less chance of the prop coming out of the water and racing with the longer shaft.<img src=icon_smile_big.gif border=0 align=middle>

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Bryan Beamer
Master Marine Consultant

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USA
1038 Posts

Response Posted - 08/18/2003 : 12:32:50

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote> meaning one of the advantages of a 25" shaft on boat with as much freeboard as a C25 is the realative position of the powerhead of the motor when pull starting, as my lonshaft (20") motor is sort of a pain to lean over the transom to grab the cord. Beyond that I cannot really think of a great advantage of a 25" shaft for the C25.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Long shaft means the captivation plate is deeper into the water.

Bryan Beamer
<img src="http://im1.shutterfly.com/procserv/47b3d935b3127cce8ab87c3b48020000000010" border=0>
Daylight Again
C250wk #495
2003 National Champion

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lancej
1st Mate

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81 Posts

Response Posted - 08/18/2003 : 12:38:56

you can always just mount the motor lower on the transom if cavitation is a problem with a 20" shaft motor, that's what I was thinking. All things equal, I agree a 25" shaft would be better, but they are nearly impossible to find used, and expensive new.

I didn't realize tohatsu made mercury motors as well???

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deastburn
Captain

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USA
334 Posts

Response Posted - 08/18/2003 : 22:40:53

The Honda 9.9 also comes, I believe, in an extra-long shaft (28"). My 9.9 is the older Honda model (1998) and has the extra long shaft. Even so, it constantly cavitates in chop when I am soloing. Unless you plan to sail on a millpond, I would recommend against anything shorter than a 25" shaft.

Mounting the motor bracket lower on the transom may not be a possible solution. If your motor is mounted to starboard (as it should be with all post 79 C25's--I think that is the change date), there are two issues: 1) access to the motor bracket bolts from inside the hull, which narrows the range within which you can mount said bracket, and 2) interference with the transom or the rub strip when the motor is fully raised and tilted.

Dave on "Wood Duck" (2616)

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Sea Trac
Master Marine Consultant

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Vanuatu
1357 Posts

Response Posted - 08/18/2003 : 22:51:23

And, perhaps not as importantly, 3) Submersion of the motor head while under way. <img src=icon_smile_big.gif border=0 align=middle>

J.B. Manley, Antares '85 FK/SR #4849
Grand Lake O' The Cherokees, NE Oklahoma

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 08/19/2003 : 12:13:06

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Mounting the motor bracket lower on the transom may not be a possible solution. If your motor is mounted to starboard (as it should be with all post 79 C25's--I think that is the change date), there are two issues: 1) access to the motor bracket bolts from inside the hull, which narrows the range within which you can mount said bracket, and 2) interference with the transom or the rub strip when the motor is fully raised and tilted.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>
I mounted my new bracket a few inches lower and further outboard (starboard) than its predecessor. I was limited by the shelf at the food of the quarterberth, wanting to use a substantial backing board in there. The upper bolts are as close as reasonable to the shelf, and the lowers are under it (as before). Putting the uppers under the shelf would have put the bracket too low.

As for the motor, rubrail, and sternrail, I took copious measurements at the dealer's shop to see where the tiller, cowl, and skeg were positioned relative to the transom and waterline when the motor was tilted one notch. That led to blocking the bracket out from the transom and helped determine its exact height. The result is my skeg is about 1" above the water when tilted one notch with the bracket up, and the anticavitation plate is about 6" under with nobody in the cockpit. Under way with enough speed to "squat" the boat, it almost drags the mounting board. I don't cavitate very often, and Long Island Sound has some pretty square seas and some huge wakes.

Dave Bristle - 1985 C-25 #5032 SR-FK-Dinette-Honda "Passage" in SW CT

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atgep
Master Marine Consultant

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1009 Posts

Response Posted - 08/19/2003 : 16:47:31

The Nissan/Tohatsu 8 looks like a sweet motor. If you purchase one please let us know what you think. It seems to be the perfect motor for our boats. If you are interested in a 25 in shaft it looks like they have one for the 9.8. I do like the weight. and the other specs. This motor would be a huge help in last weekends situation. It will provide what you need most....torque.

Edited by - atgep on 08/19/2003 16:48:33

Edited by - atgep on 08/19/2003 16:50:26

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RichardG
Admiral

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USA
990 Posts

Response Posted - 08/22/2003 : 13:49:03

I measured the Tohatsu 6 hp (4 stroke) long shaft at Boaters World. The shaft was 22.5", probably because they use a different method of measuring shaft length. Those extra 2.5" could make a big difference to those who have less tolerance for a heavy/expensive motor, but are able to deal sufficiently with occasional cavitation.

Also, I think the Tohatsu motors are usually less expensive than their equal Nissan or Mercury.

RichardG 81 C25 SR/FK "Sanity"

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deastburn
Captain

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USA
334 Posts

Response Posted - 08/23/2003 : 11:41:27

For many C25 sailors, cavitation is not a big problem. If you sail in usually calm waters, you may not need the power of a 9.9 or the extra weight and expense of an extra long shaft. If, on the other hand, you solo a lot (less weight in the cockpit) and tend to sail in places where harbor passages and the like build up big, steep and close together waves, cavitation becomes a MAJOR safety issue. It can cause the motor to overheat and shut down, it can destroy the water pump, and it can cause rapid loss of control of the boat, usually in a narrow harbor entry where the options are limited. In my neck of the woods (or ocean), four and five knot currents with opposing twenty knot winds are fairly common. I very much like Dave Bristle's post--it sounds like he has the cav problem pretty much licked. My boat rarely cavs with a crew aboard and "full ahead" on the engine telegraph. But alone, I am always searching for a way to raise sail as soon as possible...

Dave on "Wood Duck" (#2616)

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ClamBeach
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3072 Posts

Response Posted - 08/23/2003 : 17:00:27

"...anticavitation plate is about 6" under..."
From what I can discern, that's the design depth for a Honda 8hp.

I've set mine up for 6" below waterline, but having an older hull, I'm a bit worried about it's apparent 'bow down' attitude at rest. If my long shaft Honda comes up short and I can't correct it with ballast, I won't hesitate to get the xtra long shaft model.

We have a very nasty bar here on Humboldt bay... second only to the Columbia River bar as a watery graveyard. On the wrong tide, it can be breaking all the way across even with relatively moderate seas.

If you're around the bar and can't make 5 kts to beat the current or your outboard quits, you may be in real trouble in a big hurry.

It's no place to have anything but a first class installation. If you're on a lake or calm waters, you can (of course) get by with much less.

I think this discussion points out how much your sailing venue dictates the equipment you need to be safe.

Currently maintaining two holes in the water...'77 Venture 23 and new to the family,
'78 Catalina 25

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Bryan Beamer
Master Marine Consultant

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USA
1038 Posts

Response Posted - 08/23/2003 : 19:24:42

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>I think this discussion points out how much your sailing venue dictates the equipment you need to be safe. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

I agree with that statement.<img src=icon_smile.gif border=0 align=middle>

Bryan Beamer
<img src="http://im1.shutterfly.com/procserv/47b3d935b3127cce8ab87c3b48020000000010" border=0>
Daylight Again
C250wk #495
2003 National Champion

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