Porpoising at high speeds

[nathan]

Hello, I have a 66 long deck hallet with a 396 chevy and a casale v drive. The boat porpoises a lot at high speeds unless I have the cav plate pushed all the way down. But I've noticed that with 3 fat dudes it the front I can pull it up like 2 notches. Do you thinking making longer cav plates would be the best solution or smaller diameter prop? Thanks in advance.

 

[STV_Keith]

I don't know squat about V-drives, but if it were an OB boat, I'd say you have a prop with too much rake, which causes bow lift.

 

[Kylemenz1]

If you don’t have pedals to go with your T-handle you’ve got to steer with one hand and operate the handle with your other hand. The idea is to “float” the bow to keep it out of the water. When it gets to high push it down, when it’s to wet bring it up. It’s a like a beautiful dance.

 

[nathan]

I don't know squat about V-drives, but if it were an OB boat, I'd say you have a prop with too much rake, which causes bow lift.

Ok thank you. I was under the impression that it was diameter that made the lift. So I'll look for a less rakey prop

 

[nathan]

If you don’t have pedals to go with your T-handle you’ve got to steer with one hand and operate the handle with your other hand. The idea is to “float” the bow to keep it out of the water. When it gets to high push it down, when it’s to wet bring it up. It’s a like a beautiful dance.

I have a set of up down pedals I'll be putting in. It just seems like I need it more tuned in before I can dance it. It hops enough to get the prop out almost.

 

[poncho]

Plate settings can make a world of difference, someone that knows more about early true flats will be able to get you pointed in the right direction.

 

[Instigator]

The Strut placement and length will play into how it performs as well. V-Drives require a whole lot more to dial in a boat but, they have a whole lot more options to be able to dial a boat in too.
It is a BIG Learning Curve if the boat isn't already close before you start.

 

[Todd Mohr]

Get rid of the hop with more horse power, blast right through the hop.

 

[nathan]

Get rid of the hop with more horse power, blast right through the hop.

It's getting a gen 6 454 and 671 this winter. But I feel the hop will be worse

 

[nathan]

The Strut placement and length will play into how it performs as well. V-Drives require a whole lot more to dial in a boat but, they have a whole lot more options to be able to dial a boat in too.
It is a BIG Learning Curve if the boat isn't already close before you start.

Can you change the strut location with out basically re classing the bottom of the boat?

 

[Todd Mohr]

It's getting a gen 6 454 and 671 this winter. But I feel the hop will be worse

The added power will carry the bow, find the nuetral spot for the cav plates. With that much power a down pedal will be needed I wouild think.

 

[wzuber]

I would venture to say it's just the way it is with that yr. Of boat if it's OEM rigging & installation. They were made to go 50mph not 70+. The whole setup is wrong for your current use. The v-drive is probably a 12 degree instead of an 10 degree Rolled forward. The shaft angle is too deep and the prop is too far aft of the balance point. Maybe try putting 1 of the fat dudes on the transom to see if that helps. Haha.i kid
More h.p. will only exacerbate your problem making it more dangerous.
That said, you maybe able to minimize it some with a prop change. Are you running a 2 blade or 3 blade? What material is it made of?

 

[nathan]

I would venture to say it's just the way it is with that yr. Of boat if it's OEM rigging & installation. They were made to go 50mph not 70+. The whole setup is wrong for your current use. The v-drive is probably a 12 degree instead of an 10 degree. Rolled forward. The shaft angle is too deep and the prop is too far aft of the balance point. Maybe try putting 1 of the fat dudes on the transom to see if that helps. Haha
More h.p. will only exacerbate your problem making it more dangerous.
That said, you maybe able to minimize it some with a prop change. Are you running a 2 blade or 3 blade? What material is it made of?

It's got a steel 2 blade. The motor has also been moved forward like 20 inches or so it seems and the case is all braced and stuff. It seems like some one was circle track racing it or something because the cav plate has little corner skags.

 

[nathan]

It's got a steel 2 blade. The motor has also been moved forward like 20 inches or so it seems and the case is all braced and stuff. It seems like some one was circle track racing it or something because the cav plate has little corner skags.

20 might been an over exaggeration but is more than a foot for sure

 

[wzuber]

Where In the hull is the v-drive located? Up near or under the dash?

 

[nathan]

Where In the hull is the v-drive located? Up near or under the dash?

Basically right under the cross brace behind the seat. The drive shaft is really short

 

[wzuber]

Ya, that's back like an OEM location. It needs to go forward about a foot or so? It's very hull and power & use dependent. Lots of variables to consider in your situation. Is it a wood deck or all glass hull?

 

[nathan]

Ya, that's back like an OEM location. It needs to go forward about a foot or so? It's very hull and power & use dependent. Lots of variables to consider in your situation. Is it a wood deck or all glass hull?

It's all glass. Is there a way to move it forward with out having to reglass the old holes and make new ones. Worried if I do that the old ones might crack and stuff. I got a lenco 2 speed I wanna put in it but there isn't much room

 

[nathan]

It's all glass. Is there a way to move it forward with out having to reglass the old holes and make new ones. Worried if I do that the old ones might crack and stuff. I got a lenco 2 speed I wanna put in it but there isn't much room

I have a 67 v hull hallet with a blown 427 in it and it's all stock location and it doesn't porpoise much at all if any

 

[wzuber]

It's all glass. Is there a way to move it forward with out having to reglass the old holes and make new ones. Worried if I do that the old ones might crack and stuff. I got a lenco 2 speed I wanna put in it but there isn't much room

The short answer is yes, f.glass required.
It's way more then just glassing and drilling a new hole though. I'm trying think of a guys name on here that could likely be very helpful to you in your quest. I'm not that guy unfortunately. When I come up with it I'll link him in. He does a lot of restorations and rigging and he may be familiar w/ your hull specifically. He's a really good guy. Another really good, smart v-drive guy here is @Terminal Velocity. He could certainly help you some too.
I've run my course of usefulness here if you can even call it that.

 

[nathan]

The short answer is yes, f.glass required.
It's way more then just glassing and drilling a new hole though. I'm trying think of a guys name on here that could likely be very helpful to you in your quest. I'm not that guy unfortunately. When I come up with it I'll link him in. He does a lot of restorations and rigging and he may be familiar w/ your hull specifically. He's a really good guy. Another really good, smart v-drive guy here is @Terminal Velocity. He could certainly help you some too.
Dave Sammons is his name but I can't recall his screen name here @ the moment..maybe somebody can fill that blank and reach out to him.
I've run my course of usefulness here if you can even call it that.

Well thank you sir, you've been helpful as I know very little about v drive set up besides putting a big motor in them!

 

[wzuber]

@Clank123 Has a ton of knowledge on these older boats, maybe he'll chime in and lend some insight.

 

[wishiknew]

Get rid of the hop with more horse power, blast right through the hop.

 

[Clank123]

Hey Nathan!
Wzuber brought this thread to my attention.
He has covered most all the bases that need to be addressed.
As discussed…
Started out life rigged for skiing.
9 degree strut at least.
12 degree Vdrive.
Motor set back in boat for original rear seat behind center deck.
A lot to discuss here.
First things first…
Measure the distance between the rear motor plate and inside of transom.
Same thing from the transom to the back of the vdrive center plate.
Is the vdrive a split case Casale?
We can make it better hopefully.
You need to get that downpedal in there for sure.
A prop ain’t gonna help it!
One more question…where do you live?
I would be up for seeing the boat live if possible.
I’m in Carlsbad, down by San Diego.
Let me know.
I’m all about talking this through on this thread, but it could pretty technical.
Let’s make this ol girl fly!

 

[nathan]

Hey Nathan!
Wzuber brought this thread to my attention.
He has covered most all the bases that need to be addressed.
As discussed…
Started out life rigged for skiing.
9 degree strut at least.
12 degree Vdrive.
Motor set back in boat for original rear seat behind center deck.
A lot to discuss here.
First things first…
Measure the distance between the rear motor plate and inside of transom.
Same thing from the transom to the back of the vdrive center plate.
Is the vdrive a split case Casale?
We can make it better hopefully.
You need to get that downpedal in there for sure.
A prop ain’t gonna help it!
One more question…where do you live?
I would be up for seeing the boat live if possible.
I’m in Carlsbad, down by San Diego.
Let me know.
I’m all about talking this through on this thread, but it could pretty technical.
Let’s make this ol girl fly!

I'll be home this weekend I'll take some measurements for you. Boats in ventura so not to far from you. I wouldn't be against to towing in down one weekend. The casale is the one with the fat bottom, not the pill shaped one but I have a pill shaped one in the shead if that's better.

 

[Clank123]

Sounds good.
Since there is no midplate in the vdrive, measure to the center of the case

 

[nathan]

Sounds good.
Since there is no midplate in the vdrive, measure to the center of the case

It's one of these (pic with no bearing cap) but i also have this style laying around (pic with the bearing caps). It has a mid plate on mine I believe. I'll get some pics for you. Do you know what style casale is better?

 

[Clank123]

It's one of these (pic with no bearing cap) but i also have this style laying around (pic with the bearing caps). It has a mid plate on mine I believe. I'll get some pics for you. Do you know what style casale is better?

It's one of these (pic with no bearing cap) but i also have this style laying around (pic with the bearing caps). It has a mid plate on mine I believe. I'll get some pics for you. Do you know what style casale is better?

Oh so you do have a split case.
Thought you had this style by the description.
If it’s a split case, measure from the mid plate.

 

[nathan]

Oh so you do have a split case.
Thought you had this style by the description.
If it’s a split case, measure from the mid plate.
View attachment 1423622

Rear plate to transom- 28"
Transom to mid plate- 72 3/4"
Angle of prop shaft to bottom of boat-12 degree
Front of prop is 8" in front on transom

 

[Clank123]

Thanks for the measurements.
After you had mentioned that the driveline is very short I was pretty sure it had a very deep strut in it.
The numbers confirmed that.
Where to go from here?
Sadly, in terms of improving performance, our choices are very limited.
The 12 degree strut is a real issue.
Much over 9 degrees is nearly impossible to get this hull to work at speeds above 75mph and be efficient.
With the current positioning of parts there is little that can be done without repositioning the strut, redrilling the propshaft hole and moving the vdrive 20 inches or so forward along with moving the engine forward to 32 inches or so.
Would be a lot of work, time and money.
Probably the only thing,(and it’s not a great fix) you could do is move the engine forward 34 inches at least to overcompensate for the strut being deep and too far back.
This would help hold the nose down, but given everything thing else out of place not the best fix.
Oh, and you have to get a down pedal in it.
Bottom line, it all comes down to how much you like the hull and the time and effort you want to put into it.
You mentioned you want to put a blower motor in it.
Might be worth looking into a hull that is already set up to run 90plus.
Interested to hear your thoughts.

 

[nathan]

@Clank123 I really like these old halletts. I'm fat and have fat friends and I like that we can walk on the bow. I'm down to do the work. Is there dis advantages of running a shallow strut angle? And I'm concerned about plugging the old holes and they being structurally sounds. I beat is up a lot.

 

[nathan]

Thanks for the measurements.
After you had mentioned that the driveline is very short I was pretty sure it had a very deep strut in it.
The numbers confirmed that.
Where to go from here?
Sadly, in terms of improving performance, our choices are very limited.
The 12 degree strut is a real issue.
Much over 9 degrees is nearly impossible to get this hull to work at speeds above 75mph and be efficient.
With the current positioning of parts there is little that can be done without repositioning the strut, redrilling the propshaft hole and moving the vdrive 20 inches or so forward along with moving the engine forward to 32 inches or so.
Would be a lot of work, time and money.
Probably the only thing,(and it’s not a great fix) you could do is move the engine forward 34 inches at least to overcompensate for the strut being deep and too far back.
This would help hold the nose down, but given everything thing else out of place not the best fix.
Oh, and you have to get a down pedal in it.
Bottom line, it all comes down to how much you like the hull and the time and effort you want to put into it.
You mentioned you want to put a blower motor in it.
Might be worth looking into a hull that is already set up to run 90plus.
Interested to hear your thoughts.

I'll check my other v drive boxes and see if they are 10s or 8s. How shallow of an angle would you recommend. And how much farther forward should the strut be?

 

[fastenuff3]

I'll check my other v drive boxes and see if they are 10s or 8s. How shallow of an angle would you recommend. And how much farther forward should the strut be?

try moving the prop back by putting some nickels in the shaft log.a 1/4 prop back is like moving motor forward a inch or ad more power

 

[Clank123]

@Clank123 I really like these old halletts. I'm fat and have fat friends and I like that we can walk on the bow. I'm down to do the work. Is there dis advantages of running a shallow strut angle? And I'm concerned about plugging the old holes and they being structurally sounds. I beat is up a lot.

No disadvantage.
8 to 8.5 degree strut would be ideal.
Could use a 9 degree.
18 or so inches forward of the transom.
V drive will go in somewhere around 94 to 96 inches.
Motor needs to be 32 or so inches off the transom.

 

[Clank123]

Easy try option is to move the engine forward 5 inches to overcome the depth and angle of the prop. No guarantees though. Oh and let one of your larger friends ride in the passenger seat.

 

[nathan]

Easy try option is to move the engine forward 5 inches to overcome the depth and angle of the prop. No guarantees though. Oh and let one of your larger friends ride in the passenger seat.

I have it all set up to get the same hallet I have but with no running gear so I'll probably leave mine how it is and then build the second one correctly. Now I just need to find out what correctly is lol.

 

[Clank123]

I have it all set up to get the same hallet I have but with no running gear so I'll probably leave mine how it is and then build the second one correctly. Now I just need to find out what correctly is lol.

They’re great boats.
Sounds like a good plan.
Drag it down here when ya get it.

 

[nathan]

They’re great boats.
Sounds like a good plan.
Drag it down here when ya get it.

Hey buddy, what is the hardware called where the propshaft goes through the bottom of the boat. Not the strut or the v drive but the part in-between those.
And do you know where I can get them?

Thank you

 

[port austin pirate]

try moving the prop back by putting some nickels in the shaft log.a 1/4 prop back is like moving motor forward a inch or ad more power

this is an old trick that I also heard about years ago, worth a try to see if it helps a little, but probably need to do some more serious changes setup the Howard up in early 80s and I do recall 32 was placement for engine , good luck be safe

 

[nathan]

this is an old trick that I also heard about years ago, worth a try to see if it helps a little, but probably need to do some more serious changes setup the Howard up in early 80s and I do recall 32 was placement for engine , good luck be safe

@fastenuff3 I'll be at the lake next weekend I'll give it a shot.

 

[done]

If it has a 12 degree strut, It will never stop trying to hop. The only thing you can do is counter it with down plate letting it have as much up plate till it begins to hop.

 

[Clank123]

If it has a 12 degree strut, It will never stop trying to hop. The only thing you can do is counter it with down plate letting it have as much up plate till it begins to hop.

Agreed.
“putting a nickel in it” is for fine tuning the ride at top speed.
A down pedal will help, but with the steep shaft angle is simply not correct for any type of high performance flatbottom.
Oh, and Nathan, the part you are referencing is called a shaft log.

 

[nathan]

Agreed.
“putting a nickel in it” is for fine tuning the ride at top speed.
A down pedal will help, but with the steep shaft angle is simply not correct for any type of high performance flatbottom.
Oh, and Nathan, the part you are referencing is called a shaft log.

Hey clank I'll be down in Temecula on the 5th picking up that second hallett. You going to be around, if I could swing by and try to get a game plan on where I need to put everything in the boat that would be sweet.

 

[Clank123]

Hey clank I'll be down in Temecula on the 5th picking up that second hallett. You going to be around, if I could swing by and try to get a game plan on where I need to put everything in the boat that would be sweet.

Darn, wish I was.
I will be in Seattle on business that weekend.
Would love to see the boat and get everything laid out for ya!