Converting a displacement hull for planning?

I am living near a river with a flowing speed of 5 Mph. My boat is a 15´dutch Sloep with a typical displacement hull. The max hull speed is slightly above the water speed, which is not really fun to go upstream
The engine has 17Hp which is more than necessary. My plan is to build a planing plate with the hope of higher speeds.
Is there any experience out there for this hull modification? How to find out minimum power for planning?

Some more data:
weight : approx. 700Kg
engine RPM max 3600
gear 1:2,6
Shaftdrive
Prop 14´x13´

 

Buy an appropriate planing boat for the job and you will be money ahead in the long run.

 

Moin Werner,

there are some ways you probably could go. In Greece and Italy some fishboats have hull "appendages" allowing for a semi displacement speed.

Some Llaut in Mallorca use the plates.

I cannot remember where we handled that topic last time, but you can send a PM to "Daiquiri" here, he knows.

Which River are we talking? Unterelbe?

Regards
Richard

 

Some displacement boats can be modified to plane but most can't. No way to tell without knowing more about the boat with section drawing or god photos of the boat out of water. As Apex said, some get there by having wings attached just under the water back aft but the boat has to be appropriately shaped for that to work.

 

The mentioned Sloep´s are mostly shaped to provide that feature. Though not to plane! Semi, was what I said.

 

You could install a plane wing or "tail" on your boat, but you'll need probably 50 HP if not more to climb over the monster bow wave a hull like that will make. In fact, I wouldn't be surprised if you needed 75 HP.

 

Thank you for Your replies!
- Its the river Rhein near Mannheim
The following video shows a Sloep with planing plate in action:
www.youtube.com/watch?v=TSFJYvfPfEc
Does anybody know the engine? It sounds like a Diesel, I can recogize 3 cyl. which directs me in the class of 30 HP.
I´m sure that 70HP brings almost everything to planing.
I´m new to the Forum and I have to learn how to include Photos. Then I will show some photos of my boat.
thanks again
Werner

 

In the other video you can see how that has been done:
http://www.youtube.com/watch?v=OtwUe8oJk88&feature=related

The motor is listed as "Red marine 27hp" with a top speed of 16kn. The speed being mostly dependant on weight, "planing area" of the bottom and power.

 

O.K. my first try for fotos:

 

Thanks liki, I knew the second clip, and I know that it could be done. Thanks to your Info, I know now that 27HP is ok. Currently I use a 17HP Sole, based on Mitsubishi. I have to solve the Question size of plate, power and weight. The 27 HP Sole or Vetus might fit, but I do not know wether it´s worth the money.
Werner

 

Here it is, see these two topics:
http://www.boatdesign.net/forums/powerboats/plane-double-ender-33183-2.html
http://www.boatdesign.net/forums/boat-design/semi-displacement-33509-2.html
Nothing else to add...

Cheers!

 

Nice, thanks!
Apart from the Llaut I did not remember the boats names.

 

planing fins

check out the Calkins bar tender line of designs. they are planing double enders famed for their sae-keeping abilities

 

In the Carolinas, many sailing fishing boats were modified to plane under power. The appendages are called hobbles locally. They are basically a horizontal board at the waterline in the aft section with a couple of metal braces. Under sail it doesn't drag too much.

 

I live in coastal Carolina Gonzo but have never seen or even heard of such devices used locally. Seen them other places but not on any traditional Carolina boats.