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Catalina/Capri 25/250 Sailor's Forums

Catalina 250 Specific Forum

Top Speed while Under Power...

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mgjessop
Deckhand

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USA
15 Posts

Initially Posted - 09/06/2006 : 15:36:59

Hello Everybody... Great site... I own a 2003 Catalina 250 Wing Keel... I have a Honda 9.9hp outboard on my boat... I take the boat to Catalina Island alot... From my boat slip in San Diego it take about 10-11 hours of motoring to get to there... It is about a 75 mile trip... I average about 6.8-7.2mph on the trip... I am running the engine at about 80% throttle... I would love to get the boat to go about 8-9mph wich would shave hours off my trip... I have thought about adding another 5hp outboard, but not sure if it is worth the cost and if it would make much of a differance!? I am also thinking about adding a Mini Kota electric motor to see if that will give me any more speed... I keep the boat as light as possible which I know helps... What is some of your Guys top speed under power? Also anybody with a 15hp motor? What is your top speed? P.S. I love sailing The boat also... I sailed it Catalina Island this summer, it only took 31 hours... LOL.... Thank you for any help...

Mat Jessop

Edited by - mgjessop on 09/06/2006 20:51:20

Buzz Maring
Master Marine Consultant

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USA
1768 Posts

Response Posted - 09/06/2006 : 15:47:08

Hi Mat,

Welcome to the group!

I'm no marine architect, so someone else will have to give you a proper answer to your speed question. Of course, that isn't going to stop me from giving you my opinion on the matter anyway

Your hull is a "displacement" hull (vs. a "planing" hull). Unless you strap a Saturn V booster to it, you're not likely to get it to go any faster than hull speed. My advice is, pray for wind, put the canvass up, and enjoy the trip.

Again, welcome to the group, and feel free to ask as many questions as you can think of ... there are some nice & knowledgeable sailors here!

Edit: Oops! 'Misspelled Mat

Edited by - Buzz Maring on 09/06/2006 15:47:57

mgjessop
Deckhand

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USA
15 Posts

Response Posted - 09/06/2006 : 15:58:50

Great to be apart of this great forum... The fun part about the trip is getting to sail back from Catalina... I put up the spinnaker and let the wind do it's job... My last trip I made it back in about 7 hours... I averaged close to 10mph under sail... There was about a 20-25 steady wind blowing me back home... I even at one point put the out board motor on at about 90% power while under sail and got her up to her fastest speed ever of 12.5mph... I know the hull speed is close to 7mph, but I know she can go much faster under the right conditions... I guess am speed freak, if you can call 12.5mph fast... LOL

PS... I had my wife remind me that we had close to 2mph current working in our favor... So we were really going about 10.5mph... It was just cool to see 12.5mph on that gps...

Edited by - mgjessop on 09/06/2006 16:16:09

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 09/06/2006 : 16:04:54

Mat,
The theoretical hull speed on our boats is about 6.14kn, as your speed increases above hull speed, the resistance due to pushing the hull through the water increases exponentially. Put plainly, for every extra knot above theoretical speed you have to cube the amount of horsepower required to do so. This presumes that you're not talking about a planing hull (ours are displacement), which is a whole other bunch of calculations. So if you want to go 2 knots faster, you need to have 8 times the horsepower (2x2x2). That means if you want to go over 8 knots, you'll need about an 80hp engine to do so. This is not to say that with favorable conditions you can't <i>sometimes </i>go that fast, but it's not something you can do every time.

If you're making in the neighborhood of 7kn on your trips, you're doing pretty well. A larger engine in the range you asked about isn't going to make a significant difference.

Here's a pretty good article on it: http://en.wikipedia.org/wiki/Hull_speed

David

Edited by - on

mgjessop
Deckhand

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USA
15 Posts

Response Posted - 09/06/2006 : 16:14:01

Thank you for the info... I never realized I need that much power... I guess you can say that with a 20-25mph wind and a large spinnaker like I have, It is adding like hunders of horse power... That is just cool... Free power from the wind... I could also just see the looks from people with a 100hp outboard stuck on the back on my boat... For some reason, I don't think the coast guard would approve... LOL...

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 09/06/2006 : 16:26:03

Mat,
One other thing to consider, a knot is faster than MPH, by about 15%. To get knots from MPH, multiply by 1.15. On my GPS, you can switch between KPH, MPH & Kn. So when the Catalina manual says that our hull speed is 6.14 Kn, that's the same as about 7.1 MPH. Another article: http://en.wikipedia.org/wiki/Knot_%28speed%29

Hope this helps.

David

Edited by - on

mgjessop
Deckhand

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USA
15 Posts

Response Posted - 09/06/2006 : 16:38:51

Thanks, again... That is what she does about 7.1-7.2mph... I guess I need to buy a Catalina 47 to get my 10mph...LOL

The plus side of going slow is I get about 20mpg... The trip cost about $10.00 in gas...

Edited by - on

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 09/06/2006 : 17:37:22

Have you considered a MacGregor 26X?

Edited by - on

mgjessop
Deckhand

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USA
15 Posts

Response Posted - 09/06/2006 : 17:49:43

Yes I looked at one. Great concept... They go like 25 mph with a 60hp outboad... I took one for a spin awhile ago, great speed, but not so great sailing... I think Catalina has much higher quality in workmanship... I own a 30ft Bayliner with twin engines, top speed close to 50mph. I cruised over to Catalinain about 2 hour, cost $500.00 in gas for the trip... The bayliner has become a nice condo on the water...

I now take the Sailboat out only and put $490.00 in my pockect everytrip...

I think I want the impossible great speed with good fuel economy... Thank you for the advice...

Edited by - on

Arlyn Stewart
Master Marine Consultant

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USA
2980 Posts

Response Posted - 09/06/2006 : 17:56:15

A lightly loaded 250 will do 7.3 knots or about 8.5 mph either offwind driven hard or on a reach with sails hardened really tight and in the right conditions without too much surf crashing.

I don't think it will do those speeds under motor. While a motor yields thrust, it also offers drag and there just isn't enough power/drag ratio to break hull speed of 6.2 knots or 7.3 mph.

Edited by - on

mgjessop
Deckhand

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USA
15 Posts

Response Posted - 09/06/2006 : 20:49:50

Thank you for the helpful advice.. It makes alot of sence... If I run the engine at full I only gain about .5mph... I can run the engine at 50% and still go about 6mph... It definatly seems like I hit a limit once I go over 7.5mph... I guess that would be due to the theoretical hull speed... It is funny that I can go so much faster with my spinnaker and a good wind that the most powerful engine I could put on the boat... Thanks again, you have saved me some money and big disapointment...

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 09/06/2006 : 21:34:26

Hi Mat... One thing that helps with the spinnaker is that you're probably sailing with some significant following seas that can help you to plane when you're on the front side of each wave. Thus, for a moment, you're not in "displacement" mode but in "planing" mode. That could be boosting the average speed your GPS calculates (over whatever interval it's set up for). I suspect your chute in 20-25 knots of wind also generates a lot more power than your outboard--I have no idea how much--but the two combined can contribute to keeping you in a partial-plane most of the time. But on engine alone, due to the prop pitch and speed, the engine can actually hold you back from getting on plane.

You can tell you're there when spray starts coming from a little aft of the bow. It's sorta like when your Bayliner starts to lift its bow--you're pushing it past its hull speed, and it has to climb over its bow wave before it can go any faster--then the sky's the limit (subject to your fuel capacity).

In sailing, the term is "Yee haw!!"

Edited by - Dave Bristle on 09/06/2006 21:37:43

mgjessop
Deckhand

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USA
15 Posts

Response Posted - 09/07/2006 : 02:03:45

I only get that speed with the spinnaker.. I am surfing the waves which is a lot of fun...

At times I have gone close to 14mph when sliding down a large swell, at which time the bow plows into the next swell and we all get a bath...

I guess I never realized just how much energy the wind can make... I have a close frend who has a 45ft hunter sailboat... He and his wife sailed it hawaii last spring... They got cought in a some really ruff weather... He has a video of them surfing down a huge 20-25 swells at close to 20mph then half the boat going under water... It is a crazy video, it gives me the shakes... I think they are lucky to be alive... I will try to see if I can post the video... Thank you for all your help...

Edited by - on

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