Delta Pad?

[BMABITY]

I see boats advertised with a delta pad and some say they dont have one. What exactly is a Delta Pad and what does it do?

 

[mentalmatt]

A simple google search returned this from PB.com.

In an effort to NOT link to PB.com, here's the google search I ran and you can see the first two results are about Delta Pads.

http://www.google.com/#safe=off&out...3,d.cGE&fp=529999fce17dc58f&biw=2185&bih=1220


From the first post:

"A delta pad makes a flat surface towards the back center keel line of the boat for an outboard to have a surface to ride on. Works great on a fast bass boat or something like that. Some of the early jets were built that way before they realized that the rounded bottoms worked much better in a jet boat for loading the pump. They can be made to run pretty good. It's just a lot easier to make a fast boat run and load the pump right with a rounded bottom. If it's a boat that runs under 70 MPH, it probably don't make that much difference."

 

[hallett21]

Only picture I have on my phone showing the bottom. Rather than being a straight V the delta pad flattens out at the keel, however it does not go immediately flat. In the case of the vector it goes a little faster but sacrifices the rough water ride compared to a straight V hull. Someone I'm sure has more knowledge on it

 

[mentalmatt]

This sort of shows a Delta Pad... At the rear, it's a flat section, rather than a straight V.

 

[VoodooMedMan]

I don't think all that is completely accurate. Ultra 24 Stealths are built with a Delta Pad. Basically the back part of the keel where the boat rides the water on plane is in the shape of a Delta. If done right gives more speed with increased stability. I don't know much but that. I also don't know why they aren't used more. With the boats flipping lately and talk of steps in the hull causing things to get squirrelly... Maybe they are best below 70 like they said though.

I know I've seen a 24 Stealth with a 525. Although I believe somebody had one built with a Teague 800 and JW made him sign liability waivers and such as that hull shouldn't really be going that fast. At 70 it's stable I can tell you that but it is a good speed and you should know how to drive. On a cold day with minimal gear, gas and people in the boat I can do 75 with my 375 horses so I'd imagine 800 ponies would get close to triple digits if not breaking them.

A builder or someone else on here has to have some better info.

Better yet let's see what RD has to say. Then figure someone else will say the exact opposite. You know like which way props turn on cats.

 

[AzGeo]

A 'true delta pad bottom' introduces 'rocker' into the keel line and provides a flat spot at or near the transom, to control 'prop torque reaction'. The 'size, depth, angle, and reason to use one' are all great topics that would be best discussed here. This kind of topic is why I come out to boating sites, just to read what everyone says about topics like this one.

 

[PlowTown Missile]

In easy terms, its a flat triangular spot on the back of the hull in the center that the boat rides on at fast speeds. It's very efficient. Boat brands that use pad bottoms to great success are Allison and Velocity.

 

[BMABITY]

So is it used in twin and single engine application? Makes sense how having a flat center in the rear of the bottom would load a single engine prop more equally. I thought that delta pads were possibly designed for this purpose, loading a single engine prop right where it's most efficient with a horizontal load of water.

 

[Civil Onrest]

Yes on the twins question. My 32 with twins has a pad

 

[RodnJen]

In easy terms, its a flat triangular spot on the back of the hull in the center that the boat rides on at fast speeds. It's very efficient. Boat brands that use pad bottoms to great success are Allison and Velocity.

It also adds to the planing ability and stability at both slower and higher speeds for some hulls.

 

[Tishimself]

In this pic you can see the flattened out area directly in front of the out drive....a delta pad is usually in triangular in shape.....

 

[AzGeo]

In easy terms, its a flat triangular spot on the back of the hull in the center that the boat rides on at fast speeds. It's very efficient. Boat brands that use pad bottoms to great success are Allison and Velocity.

It's very efficient until the water coming off the pad starts to hit the chines or other areas of the hull bottom, then it becomes a control problem. The 'false rocker' means that all the strakes and the keel on the bottom attack at a steeper angle, and this creates more lift at low and higher speeds. Pad width (at transom) angle (length) and overall original hull design will tell just how "fast" or "EFFICIENT" this addition will create in any V-hull, or mod-VP or that matter. Many 'rough water boats' don't use delta pads because the require 'tail lift' to run through rough water, that a 'pad bottom' won't provide.

 

[Bradsrvrtoy.]

I agree with AZGEO. I own a delta pad bottom boat. A small boat with the pad to be exact. (20 Cole SS) I can feel the boat get on the pad with little trim and above 3K rpm. The boat starts to run like a raped ape but you have to be careful as control comes into play. At wide open throttle and on the pad when I come off the throttle the boat tries to "find its chines" as I call it and sits back down and will rock side to side as it settles down. Believe me when its riding on the "pad," no other part of the boat is in the water! My boat kind of "takes a set" like a Vdrive when it gets up on the pad.

I believe the pads are useful in smaller boats. Heavy boats with minimal HP will not benefit. If you cant bring the boat out of the water and on to the pad, its useless. I have been in other boats with delta pads that seem to do nothing different than a true V. I believe it relates to boat size, HP, and also water conditions. When my boat is running hard and on its delta pad, I feel the ripple in the water on glass water, not reccomended for 3ft rollers. Just my opinion.

 

[Tishimself]

BTW, my first boat was an eliminator 21' sport cruiser with a 454 and a Berkeley jet. It had a rounded bottom, and worked fin. Not a fast boat though...but lots of fun. From what I have read...I think for a jet I would look more for a rounded bottom....I would however like it if anyone can school me in boat bottoms 101 when if comes to outdrives and delta's....thanks in advance..lot of new terms here I have never heard, and it is hard to keep up...

 

[STEPPCHILD]

...as far as Jet Boats go, the bottom doesn't really matter..The intake is basically a 16"x30" pad with a hole in it to suck/pump water..you are never really riding an the "pad"..The ass of the jet boat is "stuck" to the water..the "set" would be controlled by ride plates & jet-o-vator/trim angles..

...on a propeller driven boat with a well-designed/engineered pad bottom with NO breaks/HULL steps, and PROPERLY set-up X-dimensions and ancillary rigging, the Pad is the only way to FLY..

...George Linder (Shadow & Challenger)...Guilhood brothers (Powerplay)..and Steve Stepp (Velocity & Thoroughbred) my hero, and 1st V-Bottom to 100mph, all make padded hulls that are, in my opinion, STILL the fastest and safest V-Bottoms out there...

...Although they DO take some skillz to get the most out of them..I raced a 22' Velo in A-Class Offshore for years and would pick that over ANY of the wanna-be boats with the notches/hull steps and other gimmicks.. To this day, Stepp's 280-VR boat still holds the speed record for that class @ 83mph for a single 500hp IO race-spec boat..jusayin..

...do want to balance on the head of a pin or a small flat pad...?.. Once you have driven both the choice is a no-brainer...

 

[Tishimself]

How does it do with a 25' foot boat with high HP??

 

[rivrrts429]

...as far as Jet Boats go, the bottom doesn't really matter..The intake is basically a 16"x30" pad with a hole in it to suck/pump water..you are never really riding an the "pad"..The ass of the jet boat is "stuck" to the water..the "set" would be controlled by ride plates & jet-o-vator/trim angles..

I think there are jet guys who would take exception to your statement about Delta pads and jets.

If you're talking about the family cruiser then yes I'd agree.

But for a river hot rod a delta in a jet doesn't excite me much.

 

[STEPPCHILD]

...Rrat..I agree...the jump over the 80-90mph fence IS a whole nuther ballgame...was keeping it simple..:thumbup:

 

[GregG]

Here is a close up of a pad. On a small hull it is like your on a balance beam at speed.

 

[GregG]

And here is a picture of one on a larger 27 foot 24 degree V bottom.

 

[VoodooMedMan]

I'll have to get a picture of mine this weekend. That one on the 27 looks way smaller than the one on my 24.

 

[retaocleg]

I remember when the delta pad was "the" tech upgrade..........everyone started............and fountain did the variable delta...........their pad was not a true delta......four sided as the 2 sides didn't meet and was square at the front and had a variable deadrise(got flatter towards the back).............delta is a good design unless taken too far.................brother had a cole skier and the pad was sooo large, the rocker of it affected the ride(lack of power porpous) and when turning hard, you could feel a dramatic shift to the running surface............like you could feel the bottom slam from one surface to the next...................from straight, to 20 degree bank, without anything in between..........the delta was like 18 inches and went about 8-10 feet forward on a 21 foot boat..............

 

[GregG]

I'll have to get a picture of mine this weekend. That one on the 27 looks way smaller than the one on my 24.

It'll be interesting to see how wide the pad on your 24 is. What boat is it?

 

[GregG]

I remember when the delta pad was "the" tech upgrade..........everyone started............and fountain did the variable delta...........their pad was not a true delta......four sided as the 2 sides didn't meet and was square at the front and had a variable deadrise(got flatter towards the back).............delta is a good design unless taken too far.................brother had a cole skier and the pad was sooo large, the rocker of it affected the ride(lack of power porpous) and when turning hard, you could feel a dramatic shift to the running surface............like you could feel the bottom slam from one surface to the next...................from straight, to 20 degree bank, without anything in between..........the delta was like 18 inches and went about 8-10 feet forward on a 21 foot boat..............

Yep you are spot on, they came in all shapes and sizes. 18" wide on a 21 foot boat? Holy Moly that is crazy!

Here is a picture of the delta pad on a 2013 Tuff 21 which is evidently the worlds fastest single outboard "V" hull. It does 102 GPS with a stock 300XS. Pad's have there place for sure.:thumbup:

 

[VoodooMedMan]

It'll be interesting to see how wide the pad on your 24 is. What boat is it?

Ultra 24 Stealth.

 

[spectras only]

Picture of my 25'7 boat with 24* deadrise and a delta with shallow V. The V delta is 12" wide at the stern going 3/4 way to the front. Very similar to my buddy's 35' Fountain's. Reggie Fountain adds the notched transom to aid water flow to high X dimension drives for higher speeds. My boat is over 6000 lbs and yet it hops on plane quick with the modified hull without sacrificing rough water capabilities unlike standard delta pads with flat surface. Landing my boat off a wake compared to Velocity's 26 footer with flat pad, ,mine is smoother. The Velocity is a bit faster, but it's also lighter being single engined.

This video shows the pad is working for my hull. There was some small wake early in the video to bounce over it but after that it boat runs clean with spray coming off far back.
[video=youtube;iWDTnjiH7ac]http://www.youtube.com/watch?v=iWDTnjiH7ac[/video]

 

[GregG]

The small notch on the Tuff 21 does the same thing, allows the 300 to run higher by getting clean water earlier. Most pads will have a small amount of deadrise to soften the landing, but if you want those last few mph's flat is where it's at.

 

[AzGeo]

I feel that a true "Delta Pad" is not a more shallow V-section down the keel line of a hull, (as shown in some photos here) but rather an actual 'keel line angle change'. The term "Delta Pad" refers to the actual shape derived by changing the keel line within a given V shaped hull bottom mold. Back in the (as I remember) 70's, we would level (left to right) a V-bottom hull mold, and then raise the nose a given amount (say one degree). Fill the mold with water, and that would create a 'water line' in the mold. After removing all the water we would 'fill in that DELTA shaped area' and then lay up a hull. In previous posts/photos, I have seen "notches" and "lower shallow V keel sections", but as to now I have not seen a photo of an actual "Delta Pad Bottom" in this thread, as I know them. I remember some of the first ones as being, Hondo Panteras, DiMarco's, Cole's Starfire, Rod Bahner had a few also. Back then, everyone was testing out "Delta Pads", and so some tried 4" wide X 2 degrees, or 12" wide by one degree, and all kinds of combinations in between. The 'keel line" is never a straight line when a true "Delta Pad" is the design being used.

 

[GregG]

How about these?

 

[AzGeo]

The second photo looks like the 'pad' has sides on it that are not even with the V-section. It also looks like the 'pad' is parallel to the forward keel line. (at a different level/height) It may be a 'pad' bottom, but it does not look like the traditional 'delta pad bottom' as they have been done in the past. A 'delta pad' is actually just an 'angled slice' off the keel line, rising to the transom. (no vertical sides, infact it is blended into the original V-section for control at speed) Many hull bottom designs (big and small) use a narrow center section, that usually has 'very little V or a flat area in it'. This narrow center 'riding surface' may be the most deep part of a hull even with a 24 degree deadrise out to the chines. The word 'delta' in the term delta pad refers to the fact that the 'side angles are straight lines and they intersect (in a point) somewhere forward of the transom. I don't see a 'traditional delta pad' in your photos. I do feel that the 'top photo' does show a 'delta shaped pad', but it also looks like it too has 'vertical sides' on the pad section. If it does actually 'blend into the V-section' on the sides, and create 'false rocker', then it would be a 'delta pad' bottom.

 

[AzGeo]

The small notch on the Tuff 21 does the same thing, allows the 300 to run higher by getting clean water earlier. Most pads will have a small amount of deadrise to soften the landing, but if you want those last few mph's flat is where it's at.

A 'notch' at the transom acts like a 'little stand off box or o/b bracket'. It just moves the 'loaded keel/riding surface' forward and thus allows the 'X' dimension to be raised. A 'notch' would have no effect on a V-drive boat, yet a 'delta pad' does effect ALL power systems, rigging.

 

[Wicky]

Yep you are spot on, they came in all shapes and sizes. 18" wide on a 21 foot boat? Holy Moly that is crazy!

Here is a picture of the delta pad on a 2013 Tuff 21 which is evidently the worlds fastest single outboard "V" hull. It does 102 GPS with a stock 300XS. Pad's have there place for sure.:thumbup:

Worlds fastest outboard V hull??

....cough cough!!
I think Allison owned the record for a while at 128mph!

 

[VoodooMedMan]

View attachment 275181
View attachment 275182

Hope the pics help. Ultra 24 Stealth


Sent from my iPad using Tapatalk

 

[GregG]

Worlds fastest outboard V hull??....cough cough!! I think Allison owned the record for a while at 128mph!

I stand corrected :thumbup:

 

[GregG]

The second photo looks like the 'pad' has sides on it that are not even with the V-section. It also looks like the 'pad' is parallel to the forward keel line. (at a different level/height) It may be a 'pad' bottom, but it does not look like the traditional 'delta pad bottom' as they have been done in the past. A 'delta pad' is actually just an 'angled slice' off the keel line, rising to the transom. (no vertical sides, infact it is blended into the original V-section for control at speed) Many hull bottom designs (big and small) use a narrow center section, that usually has 'very little V or a flat area in it'. This narrow center 'riding surface' may be the most deep part of a hull even with a 24 degree deadrise out to the chines. The word 'delta' in the term delta pad refers to the fact that the 'side angles are straight lines and they intersect (in a point) somewhere forward of the transom. I don't see a 'traditional delta pad' in your photos. I do feel that the 'top photo' does show a 'delta shaped pad', but it also looks like it too has 'vertical sides' on the pad section. If it does actually 'blend into the V-section' on the sides, and create 'false rocker', then it would be a 'delta pad' bottom.

How about this bottom...........?

 

[Stainless]

Worlds fastest outboard V hull??

....cough cough!!
I think Allison owned the record for a while at 128mph!

That's a cool pic! Wondered where you were hiding lol!

 

[AzGeo]

How about this bottom...........?

No that is not a 'delta pad', because I see "sides" on that pad and it does not intersect the hull at the keel or the v-section. It looks like a 'pad' that is deeper in the water than any other part of the hull. It looks like you must 'drive the boat UP onto that pad' and it's curved (sharpe sided) leading edges, would make it 'unstable' (pushing water) if the boat was unable to ride all the way back on the flat area. It also looks like the 'pad' is on the same plane as the keel, which means it offers no 'false rocker' that a delta pad is known for. The bottom in this last photo would have much less drag and much better control if you made some major changes to it. We can stay here to discuss or move to PM to clear out the traffic here. I mean no disrespect, but you can reduce a lot of drag with a different design.

 

[Tishimself]

No that is not a 'delta pad', because I see "sides" on that pad and it does not intersect the hull at the keel or the v-section. It looks like a 'pad' that is deeper in the water than any other part of the hull. It looks like you must 'drive the boat UP onto that pad' and it's curved (sharpe sided) leading edges, would make it 'unstable' (pushing water) if the boat was unable to ride all the way back on the flat area. It also looks like the 'pad' is on the same plane as the keel, which means it offers no 'false rocker' that a delta pad is known for. The bottom in this last photo would have much less drag and much better control if you made some major changes to it. We can stay here to discuss or move to PM to clear out the traffic here. I mean no disrespect, but you can reduce a lot of drag with a different design.

Funny, I was thinking the same thing...in that I dont recall ever seeing a delta pad that extended lower than the hull as this one does. And by at least a half inch to an inch from the pic. Even up on plane it strikes me that it would be a heck of a drag on the hull...most pads that I have seen are flush with the running surfaces of the hull....not extended down below them... am I wrong?

 

[spectras only]

If I'm not mistaken, Baja had a delta pad since 03 on their stepless 30 footer
Took the second picture just yesterday of a 2007 Baja twin. The delta is about half way towards the bow and about 10" wide at the transom.

 

[rightytighty]

Here's my Sanger with a Delta Pad. Boat rides awesome. Sits on the pad and just motors.



Here's a pic from underneath when I got the boat. . Red is cav plate, black is speed coated hull. Alum is the the Delta Pad.

 

[AzGeo]

Funny, I was thinking the same thing...in that I dont recall ever seeing a delta pad that extended lower than the hull as this one does. And by at least a half inch to an inch from the pic. Even up on plane it strikes me that it would be a heck of a drag on the hull...most pads that I have seen are flush with the running surfaces of the hull....not extended down below them... am I wrong?

Yes. and agree that the 'pad bottom' shown, would create a tremendous 'pressure wave' under the boat until it got up and flying on the last (parallel sided area) 18" of the pad. It's like 'dragging' a 1/2" thick second boat hull, under the boat. It looks like a lot of quality effort has been put into modifying this bottom, but I don't agree with it's design. As I remember back in the 1970's, many jets, outboards and V-bottoms in general had bottom designs, and or rigging that would not 'hold the nose up' at higher speeds. Some hulls had 'hook', some were just twisted or wrong and some even had 'rocker', but most lacked the ability (right out of the mold) to be rigged with any type of power and still maintain control at higher top end speeds. I don't know "who officially did it first" but when the 'delta pad bottoms' started being produced, many stock west coast jets and outboards gained 10 MPH with no other changes. I learned back in the late 1970's that they are a great 'quick fix' for some hull designs and in others with 'very shallow deadrise', they create other major problems up at higher speeds. I am ready to learn every day, please explain what I am missing here.

 

[AzGeo]

Here's my Sanger with a Delta Pad. Boat rides awesome. Sits on the pad and just motors.



Here's a pic from underneath when I got the boat. . Red is cav plate, black is speed coated hull. Alum is the the Delta Pad.

That baby has had a ton of bottom work done to it, and it looks like all the work was in the correct direction. Just enough 'delta pad' to give a little false rocker and just enough 'flat surface' at the transom, to counteract the prop torque. Thanks for the pix, you have a "one of a kind" boat there.

 

[rightytighty]

That baby has had a ton of bottom work done to it, and it looks like all the work was in the correct direction. Just enough 'delta pad' to give a little false rocker and just enough 'flat surface' at the transom, to counteract the prop torque. Thanks for the pix, you have a "one of a kind" boat there.

Thanks much! I take none of the credit for the the work, but I get all of the fun now. It does have a new prop and rudder now..

 

[Wicky]

That's a cool pic! Wondered where you were hiding lol!

Been hanging out at the dunes!! No internet there. Hardly any cell service either. No delta pads either..

 

[AzGeo]

Most of the turds on here don't 'fly' like that and many need delta pads. Good to see that you have no need for "implants or augmentation" to get out into the fast lane. Maybe you can help us explane why some hulls need 'false rocker' and a safe flat spot to ride on. Please don't just 'point and laugh out loud'.

 

[RiverDave]

AZGeo, why do you keep calling it "false rocker?" I've always understood a true "delta pad" to be basically what you are describing by filling up a mold with a bit of water and having the nose lifted a hair.. It would be shaped like a triangle, but would also be at a different angle then the "V" was right before it. Although the transition is somewhat "sharp" it more or less is "rocker" isn't it because of the different angle?

RD

 

[fmo24]

now this is a RIDE

 

[Tishimself]

Can someone please define the word "rocker" for me...and then explain what a "false rocker" is?? Thanks....

 

[CampbellCarl]

Can someone please define the word "rocker" for me...and then explain what a "false rocker" is?? Thanks....

A 'rocker' is just like the rocker of a rocking chair, a curved area of the hull that will allow the boat to 'sit-back' onto the (hopeful) 'sweet-spot' to carry the nose. Less wetted surface = faster boat.

'False-rocker' I have no idea. Maybe like false labor pains? I dunno, George should be along soon to correct my description.......

 

[doubleeagle]

A 'rocker' is just like the rocker of a rocking chair, a curved area of the hull that will allow the boat to 'sit-back' onto the (hopeful) 'sweet-spot' to carry the nose. Less wetted surface = faster boat.

'False-rocker' I have no idea. Maybe like false labor pains? I dunno, George should be along soon to correct my description.......

A rocker is usually built into the bottom by design and runs along the entire length of the bottom.

I think what AZ is refering to as a false rocker is the aspect that the keel angle is being altered at the rear of the bottom only It is in the delta portion only the rest of the bottom foward of that has no rocker by design Hence is not a true rocker but more of a altered keel angle making the boat ride as though it had a rocker. Most true rocker boats will want to porpose at lower speeds where a false rocker will not have this tendecy