Dropdown Longshaft for Wharram Catamaran

[Chris Bretter]

Hi all
I am starting to build a 38 ft Wharram i would like to use a centre mounted Nissan SD22 with a 2-1 reduction box and a dropdown longshaft. All fairly simple Has anyone any ideas.Also perhaps a ducted prop with a rudder to assist low speed manouvering.You guys think out of the box.
Regards Chris South Africa

[boat fan]

Hello Chris , I don`t know if you have seen this :

http://www.themultihull.com/wharram/p52je2.htm

It`s a larger custom wharram , but may be of interest.

Another :

http://www.themultihull.com/wharram3/bk6.htm

http://www.themultihull.net/kd1.htm


Regards B F

[Chris Bretter]

Hi BF I had looked on the multihull site but not seen these pics.Have you tried anything like this thanks Chris

[boat fan]

Hi Chris ,

No have not tried ......

Some debate on wharram long tails here ,

http://www.multihullforum.com/forum/...sp?FORUM_ID=36

http://www.multihullforum.com/forum/...?TOPIC_ID=2761

http://www.themultihull.com/wharram3...28/am1_156.jpg

Personally I would mount an outboard in a drop down pivoting pod.

[Chris Bretter]

Will check it out now still a way off but i like my ducks in a row.Thanks for the help.Regards Chris

[Chris Bretter]

and a genset not a bad idea.Im a a bit wary of outboards and the lack of flushing .oriental air coolel outboards available now????????who knows.

[boat fan]

Originally Posted by Chris Bretter

and a genset not a bad idea.Im a a bit wary of outboards and the lack of flushing .oriental air coolel outboards available now????????who knows.

The new generation four strokes are very good these days Chris....

[Chris Bretter]

the oriental ones are air cooled diesel who knows about quality and relaiability
I like low revs with big props sorta old school thing that coupled with being a diesel mech off earth moving machinery.

[Frosty]

Drop down engine on a Wharram means that the engine is right where you dont want it. It has to be covered by an ugly box where you dont want it. Dificult to get coolant water to the engine. Noisy, smokey, bloody awfull.

[Chris Bretter]

The idea is good but it seems to cause a lot of problems its just that i want a good power source as well.A lot of hassle though.

[boat fan]

Originally Posted by Chris Bretter

The idea is good but it seems to cause a lot of problems its just that i want a good power source as well.A lot of hassle though.

Maybe a diesel / saildrive , or Shionning`s idea of vertically retracted outboards in wells. I hear what your`e saying about flushing them....and slow revs / big props....

[Chris Bretter]

a dilemma at the least.It makes sence to have a big diesel at 2200 rpm with a 15 inch prop. a 220 volt generator ,12v 200A charging,water pump, Raw water up and down the shaft all in one package .Ducted prop with rudder.
But ho to do it simply

[Frosty]

thai boat plans needed..

I think there is something here for you

[Chris Bretter]

I surely hope there is.At least some light at the end of the tunnel ..Not a train please?

[Chris Bretter]

Hi Frosty.Raw water cooling but oh so simple.Perhaps the right way to mount it in a wharram on a pivot gets rid of the universal.use it for slow speed steering.Just put on a new sump and pickup.Auto disengage if the motor is pushed up.Not sure if there are any problems with a motor at 20 degrees.But its certainly worth some thought.
This is a wonderfull blog.Thanks Chris