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Author Topic:   Deadrise on Classic Hulls
jimh posted 09-30-2001 10:05 PM ET (US)   Profile for jimh   Send Email to jimh  
I just made a quick measurement of the deadrise on my 20-foot Whaler hull (1987 Revenge). It looks like about 14-degrees of deadrise. Is this specification published anywhere?
acseatsri posted 09-30-2001 10:12 PM ET (US)     Profile for acseatsri  Send Email to acseatsri     
How do you measure deadrise, and at what point on the hull? I always thought that there was much more at the bow versus the stern. Maybe I'll check my 18 OR later this week. Going tuna fishing for the next 4 days.
Soho posted 09-30-2001 11:53 PM ET (US)     Profile for Soho  Send Email to Soho     
Okay, got me and I am not afraid to show my ignorance.... what is deadrise ?



jimh posted 10-01-2001 08:39 AM ET (US)     Profile for jimh  Send Email to jimh     
I made the measurement of deadrise as follows:

I took a large piece of cardboard, cut out a spot to fit around the depthsounder transducers, held it against the transom at the central vee of the keel, and scribed two lines on it, each flush with the bottom of the boat on either side. In other words, the scribed lines reflect the angle the boat bottom makes at the transom.

Then I took the cardboard inside, extended the scribed lines until they met, and measured the angle with a little protractor.

The lines met at an angle of 152-degrees. The deadrise is the angle that each side rises from a flat bottom. Therefore the deadrise is equal to (180-152)/2= 14-degrees.

By the way, the hull on my Whaler looks as if it has "constant deadrise", that is, the angle of the vee hull is constant throughout its length. Of course, it does flair at the bow. I mention this constant deadrise observation because this was a much-touted feature of the famous Bertram vee-hulls, although they use a deeper vee angle.

Traditional boat hull designs often had a variable deadrise, beginning at the bow with a very sharp vee and tapering to nearly a flat bottom at the stern. Ray Hunt attracted a lot of attention to the constant deadrise hull with the success of his famous MOPPIE racing boat. Apparently this same hull form idea was used in the classic Outrage/Revenge hulls as well.

LarrySherman posted 10-01-2001 10:10 AM ET (US)     Profile for LarrySherman  Send Email to LarrySherman     
I believe deadrise is always measured from the transom, as Jim has done, even if it is variable over the length of the hull.
Tom W Clark posted 10-01-2001 01:19 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

Two things:

1) Your measurement technique has introduced a slight error by measuring the angle of the bottom of the hull relative to the transom which is not at a right angle to the keel. The transom "leans" back a wee bit and thus the angle you got is somewhat steeper than the true deadrise.

A bit of trigonometry would yield the correct result and I'm not at all sure it will be a significant difference, but it may be.

2) I'm surprised by the 14()() result. I was under the impression that my 18' OR had an 18()() dead rise (though this comes from a very old memory of a Whaler dealer telling me this and thus may be incorrect). Your '87 20" hull is one of the newer Classic 20 footers introduced in 1986. I would expect it to be as steep or steeper than the 18' hull.

To answer the question, I can find no specification of deadrise in any of the Whaler literature that I have. Perhaps someone else does...

lhg posted 10-01-2001 02:20 PM ET (US)     Profile for lhg    
I'm going to rely on my 60 year old memory here! I was fortunate enough to meet Bob Dougherty at an IMTEC trade show, after he had left Whaler and was presenting his new Marlin (now Edgewater) boats. After telling him about my two Whalers, he told me about the varying deadrise on the models as part of the design process. Here is what I remember:

1. Original V-20 Outrage: 12 degrees. (he commented that this was the first of these hulls, and the 12 degrees proved to be not enough, but that it was a careful transition from the 1st generation Outrage hulls.

2. V-22 Outrage: 16 degrees (so the 1985 & later 20's would probably have this also.
(my memory is most fuzzy on this model, since I didn't have one)

3. 18 Outrage: 16 degrees

4. 25 Outrage 18 degrees.

But don't take this as the absolute truth. Maybe someone at the factory could confirm or correct these figures.

gunnelgrabber posted 10-01-2001 02:35 PM ET (US)     Profile for gunnelgrabber  Send Email to gunnelgrabber     
i've got a jan. 1996 "sport fishing'. it has a tremendous amount of good stuff in it.on page 74..deadrise on a 17' montauk..16 degrees; 17' outrage..18 degrees;19' outrage is 20 degees; 21' outrage..18 degrees. their source isn't stated.i assume bw...hope this helps...lm
gunnelgrabber posted 10-01-2001 03:16 PM ET (US)     Profile for gunnelgrabber  Send Email to gunnelgrabber     
the numbers above were from a specification section with all boats included..same issue has an article,.."The Bottom Line on Hulls".. by roger marshall, n.a...which is also good information and includes a part on deadrise.
Louie Kokinis posted 10-02-2001 12:29 AM ET (US)     Profile for Louie Kokinis    
I uploaded a spec sheet supplied by Whaler engineering on yahoo pictures. It can be found at - click on my photos.

I feel itis only right that I ask permission before I publish what may be proprietary information that accompanies pic 2.


jimh posted 10-02-2001 01:35 AM ET (US)     Profile for jimh  Send Email to jimh     
To Tom Clark: A tip of solid-geometry hat to you for pointing out the error in my meaurement technique! I had not thought of that, but you are right. The more the transom cuts the plane of the keel at an angle, the more the deadrise angle is exagerated. So my measurement--which was pretty down-and-dirty--was slightly over-stated. Maybe I should pre-cut some templates and hold them to the hull at the keel? My next approach!

To Louie K: Your scanned documents tantalize me, but I'll be darned if I can read a single number on them. They are just a bit too fuzzy to make out. Can you transcribe them or send me a clean Xerox copy and I'll transcribe them. I think people would be very interested!


Peter posted 10-02-2001 08:04 AM ET (US)     Profile for Peter  Send Email to Peter     

What does the table say the deadrise is for the 22 Guardian?

tobes posted 10-02-2001 09:29 AM ET (US)     Profile for tobes  Send Email to tobes     

I believe it's 18 degrees, L-22'3", beam 7'3"
2200 lbs, max hp 250, max hp wght 700 lbs.


Peter posted 10-02-2001 10:44 AM ET (US)     Profile for Peter  Send Email to Peter     
Thanks Tobes.

I've had an 18 Outrage and now have a 22 Revenge. Although weight is a major factor here, the 22 rides like it has significantly more deadrise.

Louie Kokinis posted 10-02-2001 11:55 AM ET (US)     Profile for Louie Kokinis    
Sorry about the poor quality. I've sent Jimh a copy , hopefully he can clean it up an post the specs.


Peter posted 10-02-2001 03:00 PM ET (US)     Profile for Peter  Send Email to Peter     
The public, factual, dimensional information easily obtained by measuring a given hull which is contained on the sheets is not proprietary, although Whaler's expression of the factual information is proprietary to Whaler. I doubt they would freely give that to Louie if it contained proprietary, confidential information.
Louie Kokinis posted 10-02-2001 07:15 PM ET (US)     Profile for Louie Kokinis    
Peter: I called CPD today and should have an answer soon. But, I'll be surprised if I get permission to publish the 3rd sheet since the numbers where never distributed to the general public.

Per Whalers willingness to give out information - I was supplied with copies of everything requested including order-sheets, build-sheets, hull & console blueprints, and lots of extra spec sheets for trailer and radar installation. My boat file is 3" thick.

The guys at Whaler went out of their way to make sure I was happy, Iim confident they would do the same for any other Whaler owner. We all have great boats, made by some really special people n who care about their customers.


Louie Kokinis posted 10-04-2001 10:52 AM ET (US)     Profile for Louie Kokinis    
Just got approval to post the 3rd page.

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