Reply
 
Thread Tools Search this Thread
 
Old 05 January 2018, 14:36   #11
Member
 
Country: UK - England
Town: Warlingham
Boat name: Rapier
Make: BWM
Length: 8m +
Engine: Inboard diesel
Join Date: Apr 2017
Posts: 4
Curing cavitation on inflatable boat

Hi there,

There two ways of curing your cavition issues - you either cut the transom down so that the anti-cavitation plate is half an inch below the transom or you obtain a well cupped stainless steel propeller of the correct pitch and see if that works!

If the latter works, it will significantly improve your boats performance but the stainless prop will hurt your bank balance - cutting a section of your transom away (slight;y wider than your clamp outboard clamp bracket) using a jigsaw is the simple and cheapest option and very straightforward.
Good luck.
__________________

__________________
Mr RIB is offline   Reply With Quote
Old 05 January 2018, 18:47   #12
Member
 
Country: USA
Town: San Diego
Boat name: Mini Beast
Make: Achilles
Length: 4m +
Join Date: Jan 2018
Posts: 5
Thanks for all of the responses.

I am most likely going to be notching the transom down 3" this weekend and giving the boat a test run. I will cut a notch wide enough for full movement of the motor and a gentle incline up to meet the rest of the transom. It will be similar to the shape of the example boat in my original post. I am not too worried about the increased chance of water coming in from this cutout. This boat will be my spearfishing rig so I will be in dive gear most of the time and it will have a bilge.

I will cover the exposed wood with some plastic and tape while testing and epoxy after I am satisfied with getting the height just right (I found an old thread with tons of good info on this). I have been doing some epoxy research while looking into restoring a well-used speargun and will most likely use the same epoxy for this job. Some trusted gun builders have recommended this epoxy for its moisture protection and durability.

I'll share some pictures of the progress as the boat comes along.
__________________

__________________
aquaboogie is offline   Reply With Quote
Old 09 January 2018, 14:33   #13
Member
 
Country: USA
Town: San Diego
Boat name: Mini Beast
Make: Achilles
Length: 4m +
Join Date: Jan 2018
Posts: 5
So I took the leap and..... Success!

I removed 3" from the transom and the boat performed great on the test run. I hit 23kt with two people and gear in the boat while running in chop. I went for a quick run on my own in a little cleaner water and hit 26kt. I need a new prop and I know these numbers will get better once installed.

I did not experience any issues with water getting close to coming over the transom. I was being really careful due to just having the raw wood covered with tape for testing. I will test further once transom is sealed back up.

Here are some pictures of the cutting process. I will follow up with some finalized pictures after I finish up the work and get it all finished and resealed.



We removed the hardware that would get in the way of the cut and masked off the area we were cutting to protect the finish around the cut. The straight cuts were made with a circular saw


After the straight cuts were done, I followed up the corned cuts with a jigsaw


The end product before mounting any hardware


Old holes filled and hardware re-installed


View from the front


A bad picture of the rear with the motor mounted in its new location. (I will get some better pics when everything is finalized.)
__________________
aquaboogie is offline   Reply With Quote
Old 10 January 2018, 03:47   #14
Member
 
Country: UK - England
Town: Retford
Boat name: Spy-sea-one
Make: Mercury
Length: 3m +
Engine: Suzuki Outboard/25/4
MMSI: 235074042
Join Date: Oct 2011
Posts: 3,625
that looks like its worked out great the cut out level with the tube top so no issues with water spot on enjoy
__________________
jeffstevens763@g is offline   Reply With Quote
Old 10 January 2018, 14:56   #15
Member
 
Country: UK - England
Town: East
Boat name: Seaflyer
Make: Humber
Length: 6m +
Engine: Evinrude
Join Date: Feb 2014
Posts: 201
Really nice job. Enjoy.
I used to have the 25hp version on a Avon S400 - happy days!
__________________

__________________
Seaflyer02 is online now   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 13:51.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.