PAD??

[Gammabusa]

Hello all,
just woundered if anyone could share some info on PAD.

Not much boats over here in Norway uses pad,
just wounder what size they are on small say 14-18 feet 60mph+++boats,
is there many different shapes,
lenghts/breadth of pad,
is there any way to calculate the size of the pad if you know the weight/speed of a given boat.?

Yes I am thinking of adding a pad on my little boat to get some stability...huh

Ronny

 

[Ron G]

Re: PAD??

I still havent got the measurments yet.but saturdday and sunday i was riding on the paddmy boat ran better than it has in a long time couldnt get a speed i was to busy driving it and trying to keep in front of the other guysdi look and see if i can find some info on the pads.maybe some of the other guys here can help on adding or modifing it i know it can be done but i have know idea how.

 

[Texasmark]

Re: PAD??

If you are talking about a pad on the bottom of the boat, good question. I see a lot of deep V hulls that would pad out nicely if you just squared off the vee 2 or 3 inches from the bottom of the boat and let it run forward parallel to the lifting strakes till it runs out. Would be a piece of cake to add an insert into the mold and make it happen.

I don't know about adding a pad to an existing hull. You need a smooth flow of water to get onto the pad I guess, but thinking.............a hydrofoil boat like the blokes use to cross the English Channel don't have a smooth flow. They just crank the water skis down into the water, get up on them, and haul butox.

Then the rest of the story is setback. Bass Boats of today have the pad stop several inches before reaching the transom which helps them achieve their speed and stability I guess....otherwise why do it. Kenny probably knows.

So much for my rambling.

Mark

 

[Dhadley]

Re: PAD??

Adding a pad won't necessairly add stability. You have to be able to keep (balance) the boat on the pad (as Ron was saying). Some boats are easier to balance on the pad than others. A Hydrostream is relatively easy to drive and keep on the pad. An Allison isn't quite that easy but is faster (generally). My old 15' Allison had a pad 4 1/4" wide and you needed to be concentrating when it was up & running. At some point, a wider & more stable pad becomes slower than a narrower pad.

Some pads are flat, some concave and some look like a small "m", sort of. I saw a boat last year that had a pad added. It was an old California type ski boat and the guy added an Allison type pad. It turned out pretty fast. I have no idea which Allison pad he copied or what else he did to the bottom.

 

[Gammabusa]

Re: PAD??

Okey,
anyone have some good pictures of pads? most interestet in the part where the bottom of boat start to be a pad....Is the pad usally same angel as rest of bottom? When running on the pad then nothing else of bottom is in the water?

Could be a fun winter project to try a little pad on my boat but I should have hade some good pictures of a FAST pad so that I had any idea of how it looks like.

Here is some picture of a boat constructet of same guy as mine, it is 17 foot but bottom is much the same on my 14 foot boat, anyone see some big pros and cons with this solution?

http://groups.msn.com/Fjordling17HT/renovering1.msnw?action=ShowPhoto&PhotoID=207

http://groups.msn.com/Fjordling17HT/renovering1.msnw?action=ShowPhoto&PhotoID=208

http://groups.msn.com/Fjordling17HT/renovering1.msnw?action=ShowPhoto&PhotoID=209

http://groups.msn.com/Fjordling17HT/renovering1.msnw?action=ShowPhoto&PhotoID=210

Thanks again,

Ronny

 

[Texasmark]

Re: PAD??

That's the right idea. That reconfigured boat looks like the cat's meow.......has the deep V for smooth riding in big waves, lifting strakes to get the hull out of the water as you speed up and now the pad when you want some serious speed.

I like it.

I don't think the pad attitide has to match (be parallel to) the floor of the boat. The boat will have some bow lift when on the pad which is really good as it gives you clearance (between the non-pad portion of the hull and the wave) on medium sized waves and makes riding on them very smooth. Been a lot of times a rough ride turned out to be real smooth by letting the hammer down and getting on top.

On this mod, you not only got the pad, you also got some engine height out of it. With the Laser II prop she should be a real screamer.......if the engine is big enough to get her going fast enough to get on the pad only.......didn't see what the hp was.

And yes, when you get on the pad correctly, nuttin in de wadda but it , the skeg and the prop. d

Mark

 

[Ron G]

Re: PAD??

heres a pic of mine i'll try to rember how wide it is but im thinking it's like 6"wide.

 

[walleyehed]

Re: PAD??

Ron...is that transducer still mounted in the location shown in the pic?

 

[Ron G]

Re: PAD??

Yea kenny.why do think it be causing some problems?

 

[walleyehed]

Re: PAD??

Absolutely....
Minumum of 14" from center-line of boat.
That there skimmer may be causing some continuous venting that doesn't need to be there.
I've moved several transducers and most rigs have picked up speed, and 1 rig, we were able to raise the engine almost another inch. Might want to pull the skimmer from the mount, lay it up on the back and run the boat...see if ya notice anything. That piece creates quite a pocket down and to the sides at the speed you are running. I'm sure the prop is running partially in that path.

 

[Ron G]

Re: PAD??

i have been noticing something at times around 55 to 60 mph..i will move it after my fishing trip this weekend.thanks Kenny that may solve some problems.

 

[Dhadley]

Re: PAD??

Here's a Hydrostream Verlro YT. It's a V bottom with a pad and a step plus a tunnel slot on each side.

 

[Texasmark]

Re: PAD??

Hey D, you'se gonna have to elaborate on this sucker man. What do you do with it and what does it do. Looks like the designer tried to get all the goodies in one hull design.

We could talk about the pros and cons of the tunnel slot. Any spray off the center hits the sponsons and can cause drag. If they used the sponsons like you'd use a 3 pt hydro then why? Pad should do the job by it'self with the spray jetting out into the slipstream, not hitting a sponson.

I remember the 3 pt hydro's back in the '50's had the sponsons forward and nothing to obstruct the spray aft.....course a little narrow pad would have helped them but that was before we knew about that.

Mark

 

[Gammabusa]

Re: PAD??

That Hydrosteam picture got me to search around and I found this site with lotsa pictures and info about pads/bottoms

http://www.hydrostream.org/index.php

I guess I have to try getting a little pad on my boat now that I have seen different types its easier to get it done,

will let you know, thanks again guys,

Ronny

 

[Dhadley]

Re: PAD??

They use the slots to trap air to lift the hull. That design came from the old APBA Mod VP (modified V bottom, production) days. The pad had to be below the outside chine. The original intent of the class was to race V bottom boats with stock motors. They used "modified" pertaining to the hulls so the hulls could be blueprinted.

Out of those rules came the XT and YT designs from Hydrostream and later the HST. Summerford built his version too called the STV (Summerford Tunnel V). Mirage built one and on and on.

We scrapped the 3 liter project for that boat and now have a 150 60* on it. We're confident it'll run in the low 80's in the 1/4 mile. Shouldnt be too hard to get 90 on top with the stock 150. A stock 3 liter would thake this boat over 100 very easily.

I had a 20' Hydrostream Vegas just like this. With a stock 200 looper it ran 88. They are very easy to drive and a blast. Very stable.

Yes, the sponsons could, in theory, cause drag at speed..............if they were in the water.

 

[Texasmark]

Re: PAD??

Ok. I'm convinced. Must know what they're doing. We didn't run anyways near that with our little 3 pts and 2 bladed props. 8)

On air lift, like the Wellcraft Airslot, I always wondered where the tradeoff was with respect to air for lift and water spray for drag. I had a trihull what was supposed to do that to some extent and I really didn't like it. The (forward mounted) sponsons were more of a hindrance; rode rough and on a cross wind made the chine dig in and got you soaking wet.

Butttttt the 19' Trisonic I/O, built back in the '70's and I think Cobalt also, had a deep V center section with lifting strakes and all, and shorter sponsons that rode real well in rough water.....course back then I couldn't afford such a beast.

Will surf the site.

Thanks,

Mark

 

[Crownie2]

Re: PAD??

I think you've hit on the reason the airslots didn't last long...:$