dead rise angle

[Scud]

2 years ago I sold my 2+3 18 1966 hull # 106.
does anyone know the deadrise angle (at transom of course) of this model and also how many years was this bottom available . I rode in a newer 18 and it pounded bad!

[BERTRAM BOY]

Dan,
I'm the one who bought the boat from you...... You must have changed your email address, because I tried to send you a couple, and they got bounced back.
By the way, It's actually hull number 105, and it has a 24 degree deadrise.
As for what year that hull was available.... 65-68. All "barrelbacks" have a sharp keel and strakes that extend all the way to the transom.
Please send me an email with your new address. BERTRAMBOY@COX.NET

BERTRAM BOY :D :D :D

[Rodger]

The barrel-back you sold and the newer 18 have the same deadrise but the newer one has a rounded keel which is noticably, not as soft riding as the boat you sold.

[BERTRAM BOY]

I have to respectfully disagree with you both. I've had a lot of time in both, and found the round keel to pound considerably less.
There are also no inner strakes to "slap" the water on re-entry.
Chris, a little technical help here!!!!!!!
BERTRAM BOY :D :D :D

[Rodger]

Many years ago I had the opportunity to ride in a Barrel-back immediatly followed by a ride in a round-keel 18. To the best of my memory, the Barrel-back rode softer. I gave credit to the sharp keel.

[CDMA]

I have spent a lot of time on this subject. After riding in both boats (I own a barrelback) I feel overall the round keel is a better riding boat. This is what I THINK is going on:

In theory the sharp keel should cut the waves better and therefore be smoother. However this only holds true if the boat lands or impacts the waves in a purely vertical manner. But in reality we know that while in the air these boats tend to rotate and land not truly vertical. For this reason I believe the round keep feels like it pounds less because if say the boat lands at a 10* angle instead of hitting the flat area on the sharp keel boat there is a more gradual U to the bottom of the hull. This coupled with the lack of full length strakes, which in my opinion, also add to the pounding upon re-entry make the round keel boat a slightly better riding boat. That being said if you can keep the sharp keel boat level it should be faster due to the extra lift created by the full length strakes.

Finally let me add a little asterick to all of this. A simple change such as a prop can alter the nature of the boat completely. So this makes comparing these issues almost a moot point. Ride in my 18 bareback with a Bravo/ Mirage then ride in a Volvo/ Round keel boat. How can you possibly ride in one or the other and say, “oh the round keel rides better”. Who knows if it is the round keel, or the prop, or the drive that is making the difference you feel.

Chris

Look at this a registry member saying that his boat isn't the best...is that a first wink

[Gearhead99]

I have owned both. Round keel, sharp keel Donzi and a Cigarette. I feel that the sharp keel is better in the rough stuff. This includes the Cigarette. They are all sharp keeled and have the inner strakes not going all the way to the transom.

I think the strakes have a lot to do with the ride.

Also, the rounded keel, now this is my $.02 worth here, seem to have a tendency to "chimewalk" more then the pointed keel. Just my observation and feeling when I was running both types of hulls. My rounded hull Donzi seemed to want to chime walk and teter back and forth, much more then the sharp keel or the Cigarette, which is a sharp keel.

Another comment. When the hull leaves the water the torque of the engine and prop have a tendence to twist the boat.....but with the tabs and the drive in the correct position you should be able to compensate for that. UNLESS....and again I say UNLESS your air time is lengthy. Then the torque will overcome the hull flying straight in the air because there isn't any force, like the water, to stabilize it.

My $.02

[Rodger]

I tend to want to agree with Gearhead99. My brother has a 24' Cigarette with a sharp keel. It rides much smoother, doesn't rock sideways nearly as much as my 22 and doesn't have nearly the tendency to launch off a wave with the boat tilted. This of course is not a real good comparison. The Cig is almost 2 feet longer, a foot wider in beam, heavier, and has less strake surface area than my 22. So, shall we keep theorizing? It does make interesting discussion.

[BigGrizzly]

When I was a kld with our 16. I had three friends with 16 also. One ran the bottom strake the rest of the way back and it road like a brickl. We all had Volvos and almost the same pitch prop. In 1966->7 this was all that was available. Mike Fennamore had an 18 battel back with a Volvo, with the same prop as me and it road harder also. I never compared two 18 together, because they wern't available and I had no time to spare time. Other things took presidence

[Formula Jr]

Yes the radius keel is a "full floater" with out the benefit of trim tabs. But we have trim tabs now. So,..... whats the problem...? Thems that were there have said the sharp keel was a bad ideal. Don's ideal........ he was'nt right about everything..... he was just right more often than not. :)

and I am not even qualified to say, but I will say, Don A. was cariried by a circle of people that knew more about boats than he did. :) ...

and I will leave you with this. The missile is a dog and a bad copy of another boat, The six hour boat. Duo (now formula)) did it better. Much better. They made that boat light where it mattered. An just try to find one. And a DUO tunnel will beat a Missile any day.

[riverrat]

my '99 '18 has the rounded keel with no tabs & a 350 mag 300hp. it rides great without chine walking. you can make it walk with too much trim. I have heard that Donzi went to this design because of the increase in hp in the boats today. the rounded keel sets up a pad riding surface. in rough water the boat will beat you to death, but on the river it's just fine. and let's face it this is a '18 ft boat! pick your water to ride in. we love our boat. it's fast & planes nice.
:D :D don't know about the old boats. I did see Scot's (now Lenny's) boat & the sharp keel was cool looking.

[CDMA]

Interesting conversation but I really don’t think it is fair to compare the 18 Donzi to the 20 foot Cig. Or any other different sized boats. I have ridden in a 20 Cig back to back with my 18 and there is no comparing them. The 20 Cig is a HUGE boat compared to an 18. So now not only are we comparing bottom differences but weight, CG, and so forth. Also despite their similar lineage after parking my 18 next to the Cig there are significant differences in hull design that you would not notice until the boats where side by side. The Cig seemed to carry its hull form farther forward then the 18.

I think a real interesting idea would be to remove the last 2 feet of the inner strakes on a sharp keel 18. This would make the strakes the same as the later round keel boats and we would be able to isolate what design feature actually made the difference.

I have spoken to Allan Brown about why Donzi changed the hull design of the 18. His explanation was along the lines of the following: The early 18 hulls with the sharp keel would have a tendency to spin out in hard turns. As you would be turning the sharp keel would hold the water, hold the water, hold the water, then just let go. This would cause the boat to want to swap ends real quick. Then Allan says “ ask me how I know this wink ” His reasoning for the shortening of the inner stakes was along the same lines. They found in hard turns the inner strake would create a disturbance in the water and lead to the introduction of air into the prop causing the prop to loose bite midway through a hard turn. Again creating the same tendency to swap ends.

This was really interesting to me because it was the first time I had ever heard an explanation like this about why the hull design was changed. However after having the 18 sharp keel boat for three years I can say that for the life of me I can’t get it to swap ends. I have tried turning as hard and as fast as I dare with no such luck. When I asked Allan why I hadn’t experienced this he looked at me straight faced and said something along the lines of “ I guess you drive like a #$%#%@”

Owen,

Maybe a DUO can run circles around a missile but who wants one…It is like owning a Formula Jr….so close but no cigar
:p :p :p Just kidding man

[CDMA]

Scott,

If there is to be any boat spinning...BYOB...bring your own boat :)

Chris

I think these X-18's take longer to sand then regular 18's...maybe it is just all the damn holes... :p :p :p

[Greg]

Chris, I also have a '66 barrelback. (in pieces) I like your idea of shortening the strakes on the 18'. I just don't want to be the first to do it. It does seem to bite alot in the corners. I read somewhere that when driving a v-hull like these, its only a v-hull till you turn, then you are driving a flat bottom. I apologize for cross posting here, but does anyone have any opinions on a keel pad? At the end of the season last year I purchased an '86 Scarab 21' with a keel pad. It was so late in the season that I only drove it a few times. You could feel it get up on the pad and ride, re-entry was'nt bad. It just seemed to drop off plane in turning.

[WOT-sup]

As a former Missle owner, I've got to ask, what's a Duo?

[Rootsy]

hmmmm and here i have been wondering for well over a year what extending the strakes on the current 16 would do.... not all of the way to the arse... but back maybe as far as the current 18's. that'd be adding about 3 - 4 feet to them... as far as ride my 16 is kinda squishy feeling upon re-entry and if you don't ease into the waves and throttle off of the crest it'll point itself straight up.

how will extending strakes effect the 16 with the current rounded keel? too much lift, but how, nose or whole hull, will it flatten out because of the extra running surface? will it aid stabilization and reduce chinewalk? increase speed? answers to questions and we shall see.....

still gonna experiment when i get the chance :)

as for the pad... talk to lenny...

[BigGrizzly]

The early 16 had longer ones than late models. Our 1966 has the same as the 18 does.