Reply
 
Thread Tools Search this Thread
 
Old 05 June 2008, 07:04   #1
Member
 
Country: Other
Boat name: "can"
Make: Joker Boat
Length: 4m +
Engine: 40hp e-tec
Join Date: Feb 2007
Posts: 88
Engine height with hydrofoils...

Hi all,
I've been reading the previous posts about the engine height and the element of cavitation. I've been running without cavitation with an alu prop for almost 6 months now and recently i've added doelfins to my setup. What i've read is, they say doelfins reduce cavitation.

so do you think i can increase my engine by one hole? and does the engine height effects the trim response? (I put hydrofoils mainly to drop down the bow in bad weather and so far it is successful.)

Thanks for your help,
Memo
__________________

__________________
memo is offline   Reply With Quote
Old 06 June 2008, 13:32   #2
Member
 
Locozodiac's Avatar
 
Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
Join Date: Sep 2007
Posts: 1,706
Quote:
Originally Posted by memo View Post
Hi all,
I've been reading the previous posts about the engine height and the element of cavitation. I've been running without cavitation with an alu prop for almost 6 months now and recently i've added doelfins to my setup. What i've read is, they say doelfins reduce cavitation.

so do you think i can increase my engine by one hole? and does the engine height effects the trim response? (I put hydrofoils mainly to drop down the bow in bad weather and so far it is successful.)

Thanks for your help,
Memo
Doel fins are good for planning faster and staying on plane with less throttle engine rpm compared to standard engines, the up-down bow issue is a matter of trim angle. Doel fins will keep you in that running position unless you change the trim angle. A hole position near the transom will make the bow go down, the farther away will rise the bow. The best is a 90% angle between engine and boat's bottom, seek a hole trim position to match angle, distribute passengers accordingly to the middle/front to balance better the boat. Doel fin might help on cavitaion issues specially on choppy waters. Other important performance factor issue is the engine height of the anticav plate to the boats bottom, a theme treated previously on the forums and recommended by engine manufacturers.

Don't confuse engine height transom/boat's bottom issues with trim angle issues. Trim angle will definitely change boats response cruise behaviour once on plane.

Happy Boating
__________________

__________________
Locozodiac is offline   Reply With Quote
Old 06 June 2008, 14:18   #3
Member
 
Country: UK - England
Town: Midlands
Make: Nautique
Length: 6m +
Engine: PCM 5.7l
Join Date: Oct 2003
Posts: 1,082
Think you've gone a bit off track there mate. He is talking about raising the engine a hole, not trimming it out by a hole.

We put doel fins on ours and they completely stopped it cavitating when it used to occasionally in turns. So maybe you could raise it a hole...you'll probably have to try it and see.
They made ours more responsive to the trim which was excellent, wouldn't of thought raising it a hole would make too much difference to the trim. If anything raising the line of thrust should make it easier to keep the bow down

Harry
__________________
simmons0 is offline   Reply With Quote
Old 06 June 2008, 14:31   #4
Member
 
Country: Other
Boat name: "can"
Make: Joker Boat
Length: 4m +
Engine: 40hp e-tec
Join Date: Feb 2007
Posts: 88
Thanks Harry, I'll probably raise it by a hole and see how it performs. Till now, i haven't had cavitation with and without doelfins, i hope i can raise it without a prob.
__________________
memo is offline   Reply With Quote
Reply

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





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 20:04.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.