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Catalina/Capri 25/250 Sailor's Forums

Catalina 250 Specific Forum

Tohatsu XLS 6hp or Honda 15?

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csmcg
1st Mate

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96 Posts

Initially Posted - 06/07/2011 : 22:59:59

Hello Everyone,

The admiral said "We need a boat with a real bathroom." I said "Yes Dear".

The result is a new-to-me C250 WK #487. The previous owner left it well cared for but very stock which will allow me to make the mistakes for myself...

I have a beautiful 88 C22 WK (now for sale) with a brand new tohatsu XLS 6hp + generator.

The C250 came with a 2001 Honda 15hp + electric start which is in good shape.

I happen to also have a 5hp medium shaft outboard which is servicable and adequate for the C22.

With the concerns regarding weight aft on a C250, I am considering putting the tohatsu on the C250 and selling the Honda as I have three outboards and two boats.

The literature on the C250 states that a 6hp is adequate but I would like some real-world opinions.

I live on a large, cold, beautiful, and unforgiving lake in the nw us with the standard wildly variable mountain driven weather. Fetch varies with wind direction as the lake is 28 miles long and 15 miles wide. Water conditions when it gets snotty resemble the short-period, high steep chop of San Francisco bay.

I have been reading through the archives starting with page 101. I'm down to 86 at the moment and the signal-to-noise ratio on this discussion board has been truly wonderful.

I grew up in a boat-building family and currently direct water rescue operations for my local fire department as well as the county's search-and-rescue organization. That said, my experience with sailboats is rather limited and I am finding this board and it's participants to be incredibly helpful.

Thanks in advance for your thoughts regarding the outboards.

Regards, Chris.

Edited by - csmcg on 06/07/2011 23:02:14

TakeFive
Master Marine Consultant

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Response Posted - 06/08/2011 : 05:29:46

I may have the same motor as you. Mine is a 2000, with the square housing (before they came out with the rounded off one). 15 hp is more than most people say you need for this boat, but it's what came with the boat. I get to hull speed at less than half throttle. But I often have to dock in 3+ knot currents, and on the rare occasion I have to "gun" the motor to make a quick stop against the current I am glad I have the extra power. I expect that the extra power would be useful if powering into a stiff headwind, so long as you don't get enough pitching to pull the prop out of the water.

10 hp seems to be typical for this boat around here. But note that Honda's 10 and 15 hp motors of that vintage are exactly the same displacement and weight. The 10 just has a restrictor to lower the top RPMs, and slightly different spark plugs. So for this vintage motor there's no weight penalty for having a 15 hp motor instead of 10.

In the latest generation Hondas (with the rounded housing) it seems like the 8 and 10 horsepower are the same motor, and the 15 is a larger displacement than the others. So don't be confused by looking at the latest specs (unless the 2001 is the newer generation with the rounded housing).

Also note that the newer Hondas with rounded housing seem to me to be a little wider and therefore might not rotate fully if placed directly on the transom. Mine has just barely enough clearance to get full rotation with the motor's tiller up (as long as I place it in just the right place on the transom). For this reason, I made a hard link to turn the motor with the rudder.

Your needs depend on your lake conditions. But if the motor is actually heavier than other options, it could easily be offset by a bag of pea pebbles in the bow. I actually have about 300 lb of ballast in my bow. With a lighter motor, I'd only need 275 lb of ballast.

Edited by - TakeFive on 06/08/2011 05:33:17

vholmstrom
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USA
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Response Posted - 06/08/2011 : 07:43:52

I have a 9.8 Tohatsu XLS (96 lbs) that came with a 4 blade high thrust prop. It pushes us to hull speed at a little over half throttle. I assume your much lighter 6hp also has the 25" shaft. Does it have a high thrust prop? If so, I would try it on the C250. You can always go back to the Honda if it feels underpowered. Plus, the Tohatsu is new, so you know how it has been treated and maintained.

Edited by - vholmstrom on 06/08/2011 07:45:05

csmcg
1st Mate

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Response Posted - 06/08/2011 : 14:59:16

Rick, Vic,

Thanks for the response. Odds are that my C22 is not going to sell before I am in the water with the 250 so I will do as Vic suggests and just try the 6. It has been great so far on the 22. No trouble moving at hull speed but the 250 is an entirely different beast.

One other aspect of this is that there are some battery projects in my future and I'm sure that the charging output of the Honda dwarfs the Tohatsu.... I have not been able to find the charging output stats for the Honda yet.

Regards, Chris

Edited by - on

TakeFive
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Response Posted - 06/08/2011 : 16:03:41

Check your motor cover near where the alternator wire exits. IIRC there is a sticker there that gives the amperage.

Edited by - on

csmcg
1st Mate

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Response Posted - 06/08/2011 : 16:08:37

Rick, will do. Thanks.

Edited by - on

TakeFive
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Response Posted - 06/09/2011 : 18:17:49

FYI, the instruction manual for every version of the BF15 (manual and electric start) says that the alternator is 6A.

Edited by - on

jbkayaker
Captain

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Response Posted - 06/09/2011 : 18:59:56

I have a 9.8 hp two stroke on my Catalina 250 WK. I would like to have available a stronger burst of acceleration or deceleration when docking than I get with 9.8 hp especially when dealing with wind or current. With 9.8 the boat is slow stopping and slow accelerating.

Do all three engines have the same shaft length ? If not then horsepower becomes a secondary consideration after picking the ones with the longest shaft. That's because 15 or 9.8 hp is barely useful if the prop is coming out of the water as the boat hobby horses going upwind in a strong wind and wave situation.

Most 250 WK owners end up putting some weight (70 to 150 pounds ???) under the V-berth to get the waterline level. I keep as much incidental stuff (cooler, tools, etc.) as possible in the V-berth instead of under the cockpit even when not racing. It makes the boat handle better with less tendency to round up. So a heavier motor can be compensated for in the same way.

Edited by - on

Stinkpotter
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Djibouti
9076 Posts

Response Posted - 06/09/2011 : 19:02:06

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by RhythmDoctor
 FYI, the instruction manual for every version of the BF15 (manual and electric start) says that the alternator is 6A.
<hr height="1" noshade id="quote"></blockquote id="quote">Uh-uh... 12 amps for electric start, 6 for manual, true down to the BF8 for the 200x ("rounded housing") models.

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csmcg
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Response Posted - 06/09/2011 : 19:12:29

Thanks all,

Honda sticker says 10A. Square housing. No manual at the moment, search has been fruitless so far.

Is the current rectified/regulated from the Honda?

The Tohatsu sailpro is 5 amps according to the docs. Unfortunately, the voltage seems to vary with rpms.

Regards, Chris

Edited by - csmcg on 06/09/2011 19:23:37

TakeFive
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Response Posted - 06/09/2011 : 19:14:40

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by RhythmDoctor
 FYI, the instruction manual for every version of the BF15 (manual and electric start) says that the alternator is 6A.
<hr height="1" noshade id="quote"></blockquote id="quote">Uh-uh... 12 amps for electric start, 6 for manual, true down to the BF8 for the 200x ("rounded housing") models.
<hr height="1" noshade id="quote"></blockquote id="quote">
I misspoke when I said "every version of the BF15." I meant BF15A.
The rounded housing BF8C thru BF15C have 12A on electric start models. But they did not come out until 2003 model year (late 2002). If the OP has the 2001 model as he states (15A instead of 15C), it is 6A.

Edited by - TakeFive on 06/09/2011 19:16:17

TakeFive
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Response Posted - 06/09/2011 : 19:22:11

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by csmcg
 Thanks all,

Honda sticker says 10A. Square housing. No manual at the moment, search has been fruitless so far.

Is the current rectified from the Honda?

The Tohatsu sailpro is 5 amps according to the docs. Unfortunately, the voltage seems to vary with rpms.

Regards, Chris
<hr height="1" noshade id="quote"></blockquote id="quote">
OK, so two of us were wrong.

I guess I was a little more right for suggesting that you check the sticker.

I went to the boat this afternoon intending to look at my sticker to verify. Unfortunately as soon as I got there the skies turned so black I could not see the sticker, and I went running for the car with lightning all around.

You can download a manual by [url="http://marine.honda.com/Owners/Manuals/models/BF15"]clicking here[/url]. Make sure to have the serial number of your motor handy. None of the manuals for BF15A indicate a 10A alternator - they all say 6A. I want to check mine, because I thought my sticker said 9A.

Rectified? I've never seen reference to it in the docs, and I don't have a scope to check.

Edited by - TakeFive on 06/09/2011 19:27:30

csmcg
1st Mate

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Response Posted - 06/09/2011 : 19:57:33

Honda motor manual (thanks Rick) wiring diagram shows both 6 and 10. Tohatsu is voltage is regulated (but varies quite a bit) with amps rated at 5, but in reality only puts out about 3 amps.

To answer previous questions, the tohatsu is a 25" shaft with the 6" pitch saildrive prop.

Thanks everyone for the info. Regards, Chris

Edited by - on

TakeFive
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Response Posted - 06/09/2011 : 20:22:23

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by csmcg
 Honda motor manual (thanks Rick) wiring diagram shows both 6 and 10...<hr height="1" noshade id="quote"></blockquote id="quote">
Oh, I didn't look there. I just looked in the specs.

Edited by - on

csmcg
1st Mate

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Response Posted - 06/09/2011 : 21:58:03

Just finished reading through this thread:

http://www.sailnet.com/forums/gear-maintenance/36963-nissan-tohatsu-6h-4-stroke-8.html

The bit that caught my eye was from a internet outboard dealer discussing a tohatsu 6hp sailpro on a boat with less displacement than the C250:

"This model engine on this particular boat was a mismatch. At best it was a borderline selection if the boat weighs 3000 lbs. For any boat over 3000 lbs it is a huge mistake. But, I understand why the six was chosen."

Great motor for a C22. Not so much for a C250. Will proably try it anyway just to satisfy my curiosity.

Regards, Chris

Edited by - on

vholmstrom
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USA
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Response Posted - 06/10/2011 : 16:20:09

I just ran some numbers through a propeller calculator. The C250 has a hull speed of about 6.2 knots which translates to about 7.13 mph. My 9.8 Tohatsu has a gear ratio of 2.08 and my prop has an 8.7 diameter with a 5.0 pitch. Estimating prop slip at 10 percent, my boat reaches hull speed at 3480 rpm.

Using the same propeller calculator and hull, a 6 hp Tohatsu sailpro with its 2.15 gear ratio and the 8.375 diameter and 6 inch pitch prop should achieve a 7.13 mph hull speed at 2998 rpm. Switching to a 5.0 pitch prop would bring the rpm up to 3597 at hull speed. The faster rpm would also allow the alternator to more effectively charge the battery. The question is would the larger diameter prop fit the Tohatsu 6 sailpro and could it get up to the required rpm? I attached the link to the propeller calculator below for those that wish to play around with it.

http://www.rbbi.com/folders/prop/propcalc.htm

Edited by - on

Stinkpotter
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Djibouti
9076 Posts

Response Posted - 06/10/2011 : 19:33:26

First, hull speed is not a reasonable objective. At that speed, you're causing the stern to squat, the bow to rise, using maybe 40-50% more fuel than you would at 5-5.5 knots. And you're making a whole lot more noise doing it.

The lower pitch prop will give you somewhat better starting and stopping thrust, but will increase your fuel consumption at cruising speed. I opted for a "high thrust" Honda on my C-25 that did just that, and had no complaints... I've often likened its stopping power in a slip to "running into a pillow against a wall", which can be useful, especially when working against currents and/or wind. And I only occasionally motored over long distances.

When I read comments here about doing hull-speed under power, my reaction is "Are you in a blood-race back to the marina?? In that case, I'll humiliate you!" (I can now make 33 knots.

) Having some reserve power to work against a strong head-wind and big waves is useful, but running at hull-speed is sort of a Hunter thing.

Edited by - Stinkpotter on 06/10/2011 19:35:00

John Russell
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Response Posted - 06/11/2011 : 13:19:33

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 First, hull speed is not a reasonable objective. ... but running at hull-speed is sort of a Hunter thing.
<hr height="1" noshade id="quote"></blockquote id="quote">Dave, you're rarely wrong but, I gotta call ya on this one. It's not a Hunter thing, more like Macgregor.

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Stinkpotter
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Djibouti
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Response Posted - 06/11/2011 : 13:31:10

Ya got me!

(How could I make that mistake?)

Edited by - Stinkpotter on 06/11/2011 15:02:39

Tradewind
Admiral

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Response Posted - 06/11/2011 : 15:56:43

Honda. No debate. Better to have the power and not need it than need the power and not have it.

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