Hull Extensions

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Kama Kat
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Re: Hull Extensions

Post by Kama Kat »

Hi Dave,
Our PDQ MV34, Kama Kat was extended this June. Please see details on Power Cat Forum. :)
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Re: Hull Extensions

Post by PDQ-Dave »

Pictures of Karma Kat are posted on the Power Cat Forum at: viewtopic.php?f=17&t=1575
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Re: Hull Extensions

Post by PDQ-Dave »

The Hull Extension project is at a major milestone today with both the Port and Starboard hull extension attached to the boat. Still lots of work to be done but getting closer. Check out progress at: http://www.PDQ36.blogspot.com
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Re: Hull Extensions

Post by Page 83 »

I can't wait to see how you're going to attach the decks.
Sandy Daugherty "Page 83" PDQ 36026
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Re: Hull Extensions

Post by PDQ-Dave »

I just found this great little video extolling the merits hull extensions. It's the Seawind 1000 XL of which was the inspiration for my hull extension project. Though some of you might also enjoy this.

http://www.youtube.com/watch?v=ws2Uc722wIo


My hull extension project is nearly complete (after 42+ days) and the extensions are looking great. We should be back in the water this week and heading south Check out my blog where I post daily progress pictures and descriptions of materials, methods and costs (more cost data soon):

http://www.pdq36.blogspot.com
Dave Kane
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Re: Hull Extensions

Post by doubledutch »

I was surprised to read the report in the link below indicating that immersed transoms had less drag. It will be interesting to see what tests on the 36 extensions indicate.

http://www.multihulls4us.com/forums/showthread.php?t=65

Henry
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Re: Hull Extensions

Post by PDQ-Dave »

Apples and oranges to compare a hypothetical 49' cat designed in 2008 to a PDQ 36 with a 2.5' hull extension.

I do however agree that at speeds above 10 knots a square transom (i.e look at every semi-displacement and planning hull powerboat ever built) is more efficient.

How would the boat in the article perform with freeing transoms and an additional 8% of waterline length? The 8% is the rough equivalent of the 2.5' hull extensions added to th PDQ 36 (36.5') to make it PDQ 36/39'. The reality is a PDQ 36 does not sail at the speeds of a 49 footer thus, water flow properties at 10+ knots are nothing more than wishful thinking. We all have had those few seconds or minutes in the teens but in reality most time is spent sailing well below 10 knots.


Here is what hull extensions can do:
--Add waterline length with minimal additional wetted surface area = SPEED
--Provide smoother laminar water flow as the water releases from the transom <10 knots = SPEED
--Reduce hobby horsing due to longer hull length = SPEED and comfort.
--Increase bouyency where every PDQ needs it in the sterns = Load carrying capacity.
--Add water tight compartment to the boat = Safety
--Add larger swim platform and dinghy dock = Convenience
--Provide more storage for items like swim fins.
--Increase resale more than the sum of the parts = Value.
Dave Kane
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Re: Hull Extensions

Post by Page 83 »

Now comes the litmus test: actual performance. Do you have notes on you boat's performance before the extensions?
What do you hope to see afterwards?

I completely agree with most of your points.

Sandy Daugherty
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Re: Hull Extensions

Post by 36041 »

Sealed bid? With a target audience of less than 100?

I'm all for recovering costs and getting paid for time spent, but is it just me or does that seem a little extreme?

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Re: Hull Extensions

Post by PDQ-Dave »

I made some notes on my boats sailing performance this summer as we sailed from Annapolis to Cape Cod and many points in between. Can't wait to get back out on the water to test things out and record some new data of which I'll be happy to share.
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Re: Hull Extensions

Post by Page 83 »

CONGRATULATIONS!
That was a lot of work! I can't wait to hear your sailing and motoring results!
Sandy Daugherty "Page 83" PDQ 36026
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Re: Hull Extensions

Post by PDQ-Dave »

Just posted pictures of the boat in the water at: http://www.PDQ36.blogspot.com

If you are interested in hull extension parts call Dave at: 206-852-5543.
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Dave Kane
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Re: Hull Extensions

Post by PDQ-Dave »

The next PDQ36 to become a PDQ36/39 will be a LRC model with hull extension parts shipping to the owner in less than a week.
Dave Kane
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Re: Hull Extensions

Post by PDQ-Dave »

Just sailed 200nm non-stop with the new hull extensions (Mystic, CT to Cape May, NJ).

Initial observations:
Clean wake. The primary goal of the project was defintley achieved with smooth water flow off the new stern extensions.
Faster under power. Motoring out of the Mystic River we ran the motors up to full RPM's and our speed was defenitley higher than pre- hull extensions. (exact numbers to be verified with two way runs to eliminate wind and current variables)
Smother ride. The boat seemed to track better and cut through waves with less pitching fore and aft.
Surfing. It seems we were surfing almost every wave with the added bouyency and lift in the sterns.
Loading/Unloading. Getting on and off the boat at the dock was a breeze and the extra deck space was very welcome for unloading/loading the dinghy.
Extra Storage. We already have our snorkel gear ready to go and stored in the new storage compartments.
Sailing Performance. Much more difficult to quantify so I took lots of video the last 200nm... videos to be posted on: http://www.PDQ36.blogspot.com
Dave Kane
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Re: Hull Extensions

Post by 36041 »

FWIW - The price has been posted.

http://www.pdq36.blogspot.com/

Looks pretty good Dave.

Tom
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