busted FENN venturi...where to get new one?

1 month 1 week ago #36069 by jmden
Hello all,

Been lurking a bit, and have a question, so time to post. A wealth of information here. What a great resource!

I'm new to surfskis and recently picked up a FENN Swordfish S. One of the venturis is  badly damaged around the open edge--boat probably got set down on a hard surface/rock and busted it.

Where can I get a new one and how do you get the things off and what's the best way to re-attach one?

I have an email into oceanpaddlersports.com re this, so they may have the answer, but I have not seen venturis for sale yet.

Also looking to incorporate bullets into the equation as my speed isn't too great yet and I understand they may help drain the footwell at lower speeds.

Thanks for the help!

Please Log in or Create an account to join the conversation.

1 month 1 week ago #36070 by robin.mousley

Been lurking a bit, and have a question, so time to post. A wealth of information here. What a great resource!

You're most welcome! 

Here are a couple of links that might be of interest, if you haven't seen them:

Bullet Scuppers (how to install)
The theory behind bullet scuppers

Where can I get a new one and how do you get the things off and what's the best way to re-attach one?

Hopefully Ocean Paddle Sports will be able to help you with the spare part. 

Probably the best approach is to grind the damaged scupper off and epoxy the new one on. 

There is a company, Republic Sports, in Durban, South Africa that makes the bullet scupper kits. 
Their email address is This email address is being protected from spambots. You need JavaScript enabled to view it.

Good luck!

Rob

Currently Fenn Swordfish S, Epic V10 Double.
Previously: Think Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...

Please Log in or Create an account to join the conversation.

1 month 1 week ago #36074 by jmden
Thanks, Rob!

I called oceanpaddlersports.com and they actually had one carbon FENN venturi cover and are sending it to me free, so that's nice. Prob helped that I made another order (spare rudder cables, carbon bullets, etc.) and have spent quite a bit there lately...! :) 

I've found some other info on this site re venturi cover placement relative to the hole in the hull. One drawing showed the opening of the venturi cover 7mm aft of the back edge of the hole, but another showed the opening of the venturi cover even with the aft edge of the hole. But it looks like for the bullet placement, generally folks agree that the forward edge of it should be placed near or into the venturi cover so there's 5-6mm of space between the the two around the circumference of each.

Any further thoughts on that placement?

Please Log in or Create an account to join the conversation.

1 month 1 week ago - 1 month 1 week ago #36078 by robin.mousley

Any further thoughts on that placement?

Check out this article (if you haven't read it already):

The theory behind the bullets

Figure 7 in particular seems to show the optimal placement of the bullets.  The article was written by the engineer who designed and computer-modeled the flows - so if anyone knows, it should be him!

The kit is designed in such a way that the bullet is positioned optimally for the scupper.  This is what it looks like:



I also edited the old article on installing the bullet kits - there was a bunch of images that had dropped out of the article.  I've put them back.  So check this out too:

Bullet Scuppers - Updated

And of course there's been plenty of discussion on the forum...!  Here's one of the threads:

https://www.surfski.info/forum/2-announcements/17995-optimal-venturi-and-bullet-placement.html

I hope that helps!

Rob

Currently Fenn Swordfish S, Epic V10 Double.
Previously: Think Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...
Attachments:

Please Log in or Create an account to join the conversation.

1 month 3 days ago - 1 month 3 days ago #36132 by jmden
oceanpaddlersports had one venturi cover left that they included in my order for free! Nice folks down there. Along with spare rudder cables, etc., I ordered their carbon bullets. So, it was grind off the busted venturi cover, then do a little gelcoat layer/fix as I managed to just nick the composite. Then I used 3M Marine Adhesive/Sealant 4200 Fast Cure (have used this stuff for years for all kinds of kayak/marine applications and it is amazing how well it holds up)  to attach the new venturi cover and the bullets after roughing up the gelcoat in those areas and a quick acetone clean up of all surfaces. 24 hr cure and out to the lake. 

A big difference was noted. At mild cruising speeds, the boat was draining and then the gurgling set in. Only time I've seen/heard that before was when I was actually surfing a wave. So, at this point, this relatively cheap exercise seems to be working well. I can't measure the drag reduction, but if the hydrodynamic engineers are right, my two venturis with bullets should not be producing less drag that one venturi with just a cover. Seems good all around.

Thanks for the help!
The following user(s) said Thank You: robin.mousley

Please Log in or Create an account to join the conversation.

Latest Forum Topics

my first surfski (4 Posts)

7 hours 24 minutes ago

Stellar SR 2G Test - beginners perspective (5 Posts)

3 days 12 hours ago
Protected by R Antispam