Thread Tools Search this Thread
Old 28 June 2010, 07:03   #1
Country: UK - England
Make: Ribcraft
Length: 6m +
Engine: Suzuki 225 Hp
Join Date: Jun 2010
Posts: 22
Long shaft on a short shaft boat?


Is it possible to run a long shaft engine on a boat designed for a short shaft engine?

What are the disadvantages if it is possible?

Reason to run a longshaft on a short shaft boat: I need a longshaft engine (6HP) for my sailing boat and like it to use a smal RIB or SIB as well.



TopQ1967 is offline   Reply With Quote
Old 28 June 2010, 08:30   #2
Country: UK - England
Town: Worthing
Boat name: Gilded Lady
Make: China
Length: 4m +
Engine: 25HP Yam
Join Date: Jun 2010
Posts: 37

Hi there mate,

I used my johnson 7.5hp longshaft on my 3.3m SIB which is designed for shortshaft.

To get to speed you will need to weight the front of to boat down as it will push the front up more rather than forward. For this i use my mate. Top speed will be a little slower as more drag but you dont really notice it.

Engine longer so weighs a little more, bit more effort to lug around.



I have now just installed a marine ply raiser on my transom to raise it by 5 inch, works well, speed better.

Im new to boating so please excuse me if i have confused you a little,

Hope this helps.

Cheers 8)

Mattywooo is offline   Reply With Quote
Old 28 June 2010, 12:33   #3
m chappelow's Avatar
Country: UK - England
Town: yorkshire
Boat name: little vicky
Make: avon ex RNLI
Length: 3m +
Engine: tohatsu
Join Date: Mar 2008
Posts: 2,310
i too run a long shaft on my boat ,as i use the same engine on my hard displacement fishing boat,,
you say your boat is a sailing boat.. a normal longshaft should be ok but i would draw the line with an ultra long or extra long saildrive engine .
down sides and depending on the type of engine and tohatsu seem the worse as there is a flat on the leg ,, though some boats can get a lot of spray kicking up and back into the boat and a slight drop in speed also the engine is going to be 5 inches lower so it means that the engine will have to be tilted up sooner when running in very shallow water and if you pick up a plaggy bag or diver in the prop you will have another 5 inches or so to lean out and clear the prop ,,advantages are that the engine wont airate or cavitate as much if going over big waves or in tight turns as the prop is always below the water ,

to stop the spay side of things i just cable tie some thick rubber spray deflectors on the leg above the water line and infill the flat on my leg with a shaped block of wood as in the pic below.
Attached Thumbnails
Click image for larger version

Name:	114.jpg
Views:	307
Size:	74.3 KB
ID:	52324  
m chappelow is offline   Reply With Quote
Old 28 June 2010, 14:52   #4
Country: UK - Scotland
Length: 3m +
Join Date: Jun 2010
Posts: 6
I have now just installed a marine ply raiser on my transom to raise it by 5 inch, works well, speed better.

Any pics matty
joebhoy18881977 is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 19:50.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.