Extended hull, extend strakes?

I bet they shortened the inner strakes to make turning more responsive,
Now you have a longer hull, you are going to make the boats turning circle bigger of course.
Maybe extend the outside strakes all the way to the stern, and the inner strakes as they are now, and try the boat out before you go to all that trouble, even before painting.
It wold be a pity to compromise turning when I don't think directional control will be compromised with the V hull, outside strakes and outboard leg ( assuming outboard power)
On water testing is going to be far more effective than guessing.

 

Sorry, at its original length the outside strakes went all the way to the transom.

 

That makes a lot of sense. I’ll extend the outer ones.

switching topics a little what’s my construction strategy for adding the strakes? I have Coosa for the core. I would assume like everything else I need to grind into the hull and use a couple layers of glass. How many layers do I need? I have 1708 but might get something lighter for that sharp an angle.

 

I don't think you have to make it too bullet proof. After a good hull sand, shape some lengths of the Coosa Board a bit under size, and glue them in place.

A working layup would be to take 1/2 inch off the tip of the peak and curve of the crown of the Coosa, layup the whole surface with one layer of 1708, and then add strips of plain matt high enough till you can sand in the sharper shape.
Even using a bit of thickened resin for any troughs wouldn't be a problem.

It looks like you have mastered the longboard

 

Just a little background:
This is a great photo for those out there who may not be familiar with the Radon hull concept.
The way it was explained to me in non technical terms was that at low speeds and when heavily laden, it pushes water ahead of it instead of cutting through it. The bow wave pushing ahead knocks down chop as it creates a smooth and bubbly carpet for it to ride over, like a landing craft hull does.
At high speeds, as the blunt bow lifts, and the boat rides fast on its more traditional bottom section, while the blunt overhanging bow effectively deflects a lot of spray
I first became familiar with Radon boats when I was commercial diver, they were known in the trade as “dump trucks”, due to their ability to safely carry staggering loads!
Nowadays they can be found in all different types of service, from pleasure boats to sport fishermen.

 

So, kapnD, what's your opinion on the strake dilemma?

 

I posted on that, but don’t see it here. Maybe there’s a parallel thread going on elsewhere?
My thought is that it’s a lot of work for a little if any gain.
The hull does not have deep vee configuration that would require a lot of help from strakes to get up and stay up on plane.

 

Thanks guys. KapnD the other thing they are know for is their excellent down swell handling. The run to the Santa Barbara Channel Islands is always down hill coming home and they were designed for commercial guys coming home with heavy loads. The drawing from the radon webpage makes the hull shape even more pronounced.

 

The outer strakes are meant to keep the flow laminar on the main part of the hull, to assist planing, otherwise the "wash" shoots out the sides.

 

So I have scoured the internet for pictures of the bottom of Radon’s without much success. I have determined that in all I could find the outside strakes go to the transom on all sizes, 18’ to 33’, so I will at least do that.

So this week the boat is winning, it feels like I’m getting nowhere and the elephant is too big to eat, so my thoughts are all across the board. I thought about buying the correct size G10 rectangle and cut it on the 45 and poof, two lengths of strake. That’s like $160, and overkill for sure. Plan B would be to make a triangular mold and mold my own strake segments to glue on the boat. I just don’t want to deal with trying to bend and shape over a reasonably sharp edge on the boat.

 

Just use coosa or offcuts or mould it over ship tape and use solid glass.

those parts shoukd cost less then $50

g10 is silly

 

Agreed.
Keep it simple.
Cut the slightly undersized shape of the strake from a light soft wood, epoxy-glass it in place and go boating.

 

Structural strenght, directional control and wake cleanliness are at stake in your question.

- Structural strenght : Have you got the internal girders extended to the transom, with sufficient material to support the engine(s) torque ? If not, then strakes are to be place as stiffeners.

- Directionnal control : Depends on the speed you want to achieve and the V of the hull (putting aside the effect of tunnels or steps). Deep V can cope with the absence of aft strakes. Instead, your hull V seems more moderate. As such, you may keep some grip by extending the outside strakes to the transom ( in yellow downbelow )

- Wake cleanliness : A turbulent boundary layer forms under the stern, and this boundary layer grows with the lenghts. A planning hull will generally take benefit from this phenomenon, as it lower the viscous drag, and so the fuel consumption. However, depending on the planning angle of the boat, the stern angle and the boat speed, the wave drag can also be increased. In that case, stern strakes will limit this other phenomenon. ( in green downbelow )

Cheers,

 

Thanks @Alan Cattelliot !

I got back in the ring with the hull yesterday and figured out dimensions and angles for the strake core. I’ll be cutting Coosa and fiberglass this weekend if not tonight!

 

Step two: