Educate me about strakes

[N of the rvr]

Maybe this has been talked about here before. But what is the theory about how strakes work? Some of the boats I've had have several while others only have one on each side, some run all the way to the transom while others stop about 3/4 of the way to the back. Thanks for any info.

 

[FreeBird236]

Maybe this has been talked about here before. But what is the theory about how strakes work? Some of the boats I've had have several while others only have one on each side, some run all the way to the transom while others stop about 3/4 of the way to the back. Thanks for any info.

AzGEO to the courtesy phone.:thumbsup

 

[Waffles]

Theoretically, I think i understand what strakes are supposed to do: provide lift, "traction" when turning, and deflect spray. But.....im still learning so i might be completely wrong lol

 

[RiverDave]

As a vee is cutting through the water the shape is naturally providing lift. Water is running up angle of the vee, if there is a lifting strake there it will redirect that water back down creating even more lift.

that's about all I got while I am driving..

 

[twocents]

Not intentionally wanting to complicate the discussion, but remember all strakes are not the same. I think we're all familiar with conventional lapstrakes that you see on nearly all popular vee-bottom hulls. There is, however, a vee-hull design (which is patented) called the Z-Plane used by Stingray Boats (a relatively lowered priced production built boat with models in the 17' to 23' range out of Hartsville, South Carolina). It is difficult to describe in words how the Z-Plane configuration differs from conventional vee-botom lapstrakes but if you Google Stingray Z-Plane hull I'm sure you'll find some diagrams comparing the two. Having driven a number of Stingrays, I can vouch that the Z-Plane (using moderate stern drive power options from 200 to 375 hp) is the more efficient running surface, and Stingray has volumes of performance data on speed, acceleration and fuel economy to back this up.

 

[Bigbore500r]

Not intentionally wanting to complicate the discussion, but remember all strakes are not the same. I think we're all familiar with conventional lapstrakes that you see on nearly all popular vee-bottom hulls. There is, however, a vee-hull design (which is patented) called the Z-Plane used by Stingray Boats (a relatively lowered priced production built boat with models in the 17' to 23' range out of Hartsville, South Carolina). It is difficult to describe in words how the Z-Plane configuration differs from conventional vee-botom lapstrakes but if you Google Stingray Z-Plane hull I'm sure you'll find some diagrams comparing the two. Having driven a number of Stingrays, I can vouch that the Z-Plane (using moderate stern drive power options from 200 to 375 hp) is the more efficient running surface, and Stingray has volumes of performance data on speed, acceleration and fuel economy to back this up.

Here's a drawing of the Z plane strakes - hull shape. They say the varying angles of the hull between the strakes help air the boat out easier and get it "unstuck" from the surface tension of the water. The center most hull area between the other strakes is inset at a steeper angle (slightly)

 

[guest hs]

Here's a drawing of the Z plane strakes - hull shape. They say the varying angles of the hull between the strakes help air the boat out easier and get it "unstuck" from the surface tension of the water. The center most hull area between the other strakes is inset at a steeper angle (slightly)

View attachment 507742

I call B.S. on this if it was any good Schiada would have used it years ago.

 

[wsuwrhr]

Here's a drawing of the Z plane strakes - hull shape. They say the varying angles of the hull between the strakes help air the boat out easier and get it "unstuck" from the surface tension of the water. The center most hull area between the other strakes is inset at a steeper angle (slightly)

That is how the last strake is on my Anthony.

 

[Bigbore500r]

I call B.S. on this if it was any good Schiada would have used it years ago.

Hey I never said it worked....lol
Just what I read

It could be on the same level as HTM'S fake NACA ducts

 

[guest hs]

Hey I never said it worked....lol
Just what I read

It could be on the same level as HTM'S fake NACA ducts

Ooooooooooooh snap!

 

[AzGeo]

Is there a point to the general question, as far as your personal experiences with different hull bottom designs ?

If this is just a general 'hull design, deadrise, strake' question, we can all gather around the campfire and talk about this until we run out of beer ............

 

[wsuwrhr]

Is there a point to the general question, as far as your personal experiences with different hull bottom designs ?

If this is just a general 'hull design, deadrise, strake' question, we can all gather around the campfire and talk about this until we run out of beer ............

I got plenty o beer

 

[SBMech]

Is there a point to the general question, as far as your personal experiences with different hull bottom designs ?

If this is just a general 'hull design, deadrise, strake' question, we can all gather around the campfire and talk about this until we run out of beer ............

I'll listen if you have knowledge to share, or link a previous post where you have some thoughts. :thumbsup

I'm always willing to learn something.

 

[N of the rvr]

Is there a point to the general question, as far as your personal experiences with different hull bottom designs ?

If this is just a general 'hull design, deadrise, strake' question, we can all gather around the campfire and talk about this until we run out of beer ............

Yes, there is a point. I've had a new race boat built its a pad bottom with only one strake on each side. I also have a used race boat, pad bottom with three strakes on each side, nether boat is rigged yet. They are the same length (19'-6") they both will run a 300xs, deadrise is about the same on each boat. I would sell the used boat unless it will handle rough conditions "much" better than the new boat, if it will then I may keep them both. Thanks in advance for any input.

 

[Faceaz]

I call B.S. on this if it was any good Schiada would have used it years ago.

http://patft.uspto.gov/netacgi/nph-...5,063,868.PN.&OS=PN/5,063,868&RS=PN/5,063,868

 

[2FORCEFULL]

what about golf ball bottom?

 

[shueman]

The science of hull design ...

[video=youtube;Lv9IBDRv6_A]https://www.youtube.com/watch?v=Lv9IBDRv6_A[/video]

 

[AzGeo]

Yes, there is a point. I've had a new race boat built its a pad bottom with only one strake on each side. I also have a used race boat, pad bottom with three strakes on each side, nether boat is rigged yet. They are the same length (19'-6") they both will run a 300xs, deadrise is about the same on each boat. I would sell the used boat unless it will handle rough conditions "much" better than the new boat, if it will then I may keep them both. Thanks in advance for any input.

Well, first we need to know where the 'first strake' is located relative to the keel, on each hull . Looking from the bow, are the first strakes, '4",6", 8"' up from the most deep part of the keel .

If both hulls are similar, do both have their 'first strakes' at the same place, relative to their keels ?

On both hulls, are those first strakes of the same size (width), shape, and length ? Are the 'pads' the same, angle, width, length ?

Taking a guess here, but are the hulls by the same company, or the latter is an 'improved model' of the original 'multi strake design' ? Improved 'splash' off an original ?

Assuming they are of the same original design or design concept, years of racing and testing have shown a reduced need for the 'other strakes', in rough water or bouy turns . Assuming the 'other/outer strakes' are not used on straightways, nor under normal race conditions .

The original multi strake design does give the hull bottom some extra 'stiffness', due to the 'rib like shapes' of the lamination's in it's construction, but that can be easily counteracted by using 'fillers', like balsa core . The 'multi strake' hull will have 'extra lift' when the boat powers thru larger waves/wakes, because of the 'extra strakes . This is 'unwanted lift' at 80/100 MPH . Going thru tighter high speed turns, you trim the keel DOWN and proceed into the turn . At this critical time, those 'extra strakes' may be 'wetted' and add LIFT, at a time you don't want it, and so that LIFT causes the keel to 'skip' in the turns .

In theory, the 'single strake hull' will quickly trim DOWN, settle the keel and roll EASILY INTO the turn without unwanted LIFT and this will smooth out those turns .

If the hull is used only at 'idle speeds or above 50 MPH racing', the designers may have found that making 'minor changes' to the first set of strakes, along with the 'pad', to be PLENTY of LIFT for the gross weight of the boat, they may have removed the others, only for those 'bad handling' reasons .

Example; the photo below shows the area I am asking to be measured, between the keel line and the first strake . The boat in the photo has a distance of 14" from keel line up to the first strake .

 

[Big B Hova]

Too many strakes can make a man keel over.

Get it! LoL

 

[cicchetti_24]

Hey I never said it worked....lol
Just what I read

It could be on the same level as HTM'S fake NACA ducts

Hey! Easy turbo haha jk

 

[Bigbore500r]

Hey! Easy turbo haha jk

Lol

 

[138]

Yes, there is a point. I've had a new race boat built its a pad bottom with only one strake on each side. I also have a used race boat, pad bottom with three strakes on each side, nether boat is rigged yet. They are the same length (19'-6") they both will run a 300xs, deadrise is about the same on each boat. I would sell the used boat unless it will handle rough conditions "much" better than the new boat, if it will then I may keep them both. Thanks in advance for any input.

So what did you buy?