How fast is the O'day 240?

[LoveTwoSail]

This is our first year sailing the O'day 240, and we sail on a small Pennsylvania lake with limited area and irregular winds. We purchased the boat in late summer of 2012, and then spent October through April 2013 making some modifications and adding some items that we wanted.

One of the items added was a new Humminbird 597ci HD combo fishfinder/chartplotter. With this, we get water temperature, depth, fish finding and GPS speed. We regularly hit speeds over 6mph, sometimes into the 7mph, and briefly hit 7.9mph. Does this seem correct? The GPS speed IS SET to mph.

How fast is your O'day 240? Have you checked the speed on your boat? What do you get in either mph or knots? I can use a conversion chart if necessary.

[This boat seems a lot faster than our Aquarious 23, but that had a paddle wheel transducer, which is supposed to be less accurate (because of crud build up on the paddle wheel) than GPS speed.]

As we come between the docks, on our way to our slip, I had a set location where I would put the motor into neutral and coast into the slip. The first time we did it with the 240, we came in way too fast. This boat slides through the water much easier than the Aquarious. I now have to put the motor into neutral several boat lengths sooner to enter the slip at a nice, slow speed.

 

[Pat]

Your 240 seems much faster than our 272 LE...we have hit over 7 on our gps, but only when sailing on a broad reach....and 6 knows is not normal on our lake for us but we may be sailing in windier conditions which might actually be slower...I would sail normal on our boat is 4.5-5.8....we do that a lot, but over 7 is unusual. Enjoy the summer sailing. Pat

 

[Mickstr]

For what it's worth LoveTwoSail, the paddlewheel knot meter gives you speed through the water, while the GPS is giving you speed over land. You can't compare the two without some kind of compensation...

Additionally, are you sure both devices gave you mph? Is it possible the 23 was using knots, and the 240 mph? For any given speed, the mph would be a higher number than the same speed measured in knots...

 

[Pat]

I have my Garmin gps set on knots vs. mph. There is definitely a difference...Pat

 

[LoveTwoSail]

We spent the weekend on the boat. Had visitors on Saturday who had a cell phone with GPS. Light winds which took us to around 4.1 to 4.3 mph max. His GPS speed matched my fish finder GPS speed. So it appears that my GPS speed as shown is accurate.

Also, made a run with the motor (9.8hp) at top speed, the max speed varied between 7.2 and 7.4 mph.

Has anyone else checked the speed on their O-Day 240 with GPS?

My main and furling jib sails are older; but someone in the past from Long Island may have raced the boat, since the boat includes extra hardware, a 150 genoa and a spinnaker. I haven't tried to use these sails since any benefits would seem to be unnecessary when compared to work involved.

 

[Sparky3]

I have also recorded 7.4 MPH (was varying from ~7.35 to 7.45) on my GPS heading north on Lake Huron crossing Saginaw Bay. This was under motor power (Evinrude 9.9) as I just bought the boat last year and haven't had much sailing time on it yet.

I know what you mean about it not wanting to stop when docking. My outboard is a long shaft but not a "sailor model" and does not have a reverse lock so the motor starts to lift out of the water when giving it much throttle in reverse. I am having it converted to an extra long shaft with a reverse lock this winter which should cure that. I also installed a new prop more suited to a sailboat application as the outboard and prop was more of a fishing boat setup.

 

[Pat]

You do need to have your GPS set on knots rather than miles per hour for an accurate
reading. There is a formula for conversion of miles per hour to knots...our 272 will go faster proportionately in a light wind vs. a heavy wind. I was told early on that whenever a portion of the hull goes into the water that is not designed to go into the water...such as toe-rails, that we are probably going slower than we would with a reef in the main and the boat sailing on her designed water line....Have fun. !

 

[cbourne200]

I previously had a Columbia 23T, now an O'Day 272.

Lots of things come into play - LWL, style keel, clean/fouled bottom, etc...

The 272 is definitely faster than the 23T, but I attribute most of it to LWL.

 

[Jackdaw]

On a deep reach under jib and main, most boats in flat slack water will max out at the hull speed (calculated on hull length, not LWL) plus maybe 0.5 knots.

So for your 240 (lets use 24 to be charitable), gives us 6.6 + 0.5 = 7.1 knots (or 8.2 MPH) through the water.

 

[Sunbird22358]

Hull speed is calculated based on LWL (Waterline length) and the formula is 1.34 x square root of hte waterline length and gives hull speed in knots.
Many boats will occaisionally exceed "hull speed" under the right conditions, although usually not by very much, a broad reach (heading approximately 90 degrees to the wind) is the fastest point of sail under most conditions.
My DS II has a 16' LWL so hull speed is 5.36 knots, on a broad reach I have hit 7.5 knots+ easily. However, the DS II is a planing hull not a true displacement hull, so hull speed really is not the limiting factor as on a dispalcement hull boat. Still, on a broad reach it is still well within hte realm of possibility for a 240 to exceed "hull speed".
Hull speed for a 240 (1.34 x sqrt of 20'10") is about 6.12 knots (7.04 mph).
1 Knot = 1.15 mph

 

[Jackdaw]

Hull speed is calculated based on LWL (Waterline length) and the formula is 1.34 x square root of hte waterline length and gives hull speed in knots.
Many boats will occaisionally exceed "hull speed" under the right conditions, although usually not by very much, a broad reach (heading approximately 90 degrees to the wind) is the fastest point of sail under most conditions.
My DS II has a 16' LWL so hull speed is 5.36 knots, on a broad reach I have hit 7.5 knots+ easily. However, the DS II is a planing hull not a true displacement hull, so hull speed really is not the limiting factor as on a dispalcement hull boat. Still, on a broad reach it is still well within hte realm of possibility for a 240 to exceed "hull speed".
Hull speed for a 240 (1.34 x sqrt of 20'10") is about 6.12 knots (7.04 mph).
1 Knot = 1.15 mph

You're right, that might be true in how it is calculated it in books, but its not what happens in the real world. It's one of the reasons that actual hull speeds are higher then reported in 'official' data.

The actual hull speed of any boat is based on the waterline length of the boat when it is actually sailing at hull speed. In this state, it is:

1. Heeled
2. Pressed into the water
3. Riding between two waves.

That has the effect of extending the waterline length to almost the length of the hull (not necessarily LOA). Designers used to exploit this for rule reasons. It also helped in light airs.

Look at the C&C40. LOA is 40 feet, but the LWL is 31! I guarantee it's actual 'hull speed' is closer to 8.5 and not 7.5 knots.

Old rating rules (CCA and IOR) based rating calculations on static LWL, so the rules favored overhangs. New rules do not, so now most boats are plumb on both ends.

One lasting advantage to overhangs is that it limits waterline length (and whetted surface area) in light airs, so the boat is less sticky. When the boat powers up, the waterline length extends.

PS - The reason I say hull length and not LOA is that many boats (including the Oday 240 I think) include their transom hung rudder as part of their LOA calculation. That clearly will not help hull speed. Also most owner are saddened to find their boat is actually 18 inches shorter than they expected.