Reply
 
Thread Tools Search this Thread
 
Old 25 February 2020, 13:19   #1
Member
 
Country: UK - England
Town: Cambridge
Boat name: Drifting Away
Make: Ribcraft
Length: 6m +
Engine: Twin Evinrude 135's
Join Date: Feb 2020
Posts: 2
Ribcaft 6.8 transom clearance cat 3 survey

Just was about to get my vessel surveyed however we had an issue with the transom clearance. Has anyone else had issues?
__________________

__________________
Boatserv is offline   Reply With Quote
Old 25 February 2020, 14:20   #2
Member
 
Country: UK - England
Town: Dorset
Boat name: Seabadger
Make: Ribcraft / Delta
Length: 5m +
Engine: Various
MMSI: -
Join Date: May 2010
Posts: 666
I think its a common issue on many ribs inc earlier RC in achieving the nominal 250mm freeboard requirement in all laden conditions. Lots of solutions on here. Fugro have a 6.8 work rib which has a false second transom clamped between the tubes at the forward face of the A frame. On mine I've fabricated a small GRP well around the cut-out in the transom which effectively raises the height of the transom and works well without compromising any deck space. Delta ribs often come with an in house solution from new. Google images of Delta ribs and you'll see what I mean. Good luck
__________________

__________________
diver 1 is offline   Reply With Quote
Old 25 February 2020, 14:26   #3
Member
 
Country: UK - England
Town: Dorset
Boat name: Seabadger
Make: Ribcraft / Delta
Length: 5m +
Engine: Various
MMSI: -
Join Date: May 2010
Posts: 666
Here's some examples of solutions I've seen
Attached Thumbnails
Click image for larger version

Name:	20170122_143854.jpg
Views:	228
Size:	197.4 KB
ID:	132218   Click image for larger version

Name:	20180520_073916.jpg
Views:	212
Size:	140.1 KB
ID:	132219   Click image for larger version

Name:	IMG_4280.jpg
Views:	201
Size:	133.6 KB
ID:	132220   Click image for larger version

Name:	52763f8d-e0c0-442c-9e90-13c0d4718212_medium640.jpg
Views:	221
Size:	102.0 KB
ID:	132221  
__________________
diver 1 is offline   Reply With Quote
Old 25 February 2020, 15:07   #4
Member
 
Country: Ireland
Town: Ennis
Boat name: pac 22
Make: Halmatic
Length: 6m +
Engine: inboard
Join Date: Aug 2018
Posts: 118
can a vessel with an open transom attain cat 3 or 4. My halmatic has a transom height of 150mm. I don't do any commercial so wouldn't be familiar with the regs. some open transom boats are round the world yachts.
__________________
mikehhogg is offline   Reply With Quote
Old 25 February 2020, 15:48   #5
Member
 
Country: UK - England
Town: Waterlooville
Boat name: Tickler
Make: Halmatic P22
Length: 6m +
Engine: Inboard Diesel 140HP
MMSI: 235115642
Join Date: Sep 2015
Posts: 1,200
RIBase
Quote:
Originally Posted by mikehhogg View Post
can a vessel with an open transom attain cat 3 or 4. My halmatic has a transom height of 150mm. I don't do any commercial so wouldn't be familiar with the regs. some open transom boats are round the world yachts.
Mike

I'm surprised that your freeboard is only 150mm I think you might be confusing height of transom from the deck and freeboard.

If your waterline is co-incident with the top of the sterndrive, which is where mine is, it will give you 250mm freeboard.

I think possibly the P22's were designed to a rescue boat code that probably also included a 250mm transom freeboard requirement. This is a bit of conjecture though.

The regs only seem to give you some slack in transom height if you operate in Cat 6 waters.

It doesn't help the OP though.
Attached Thumbnails
Click image for larger version

Name:	P22 Transom.JPG
Views:	173
Size:	66.2 KB
ID:	132222  
__________________
GuyC is offline   Reply With Quote
Old 25 February 2020, 16:13   #6
Member
 
Country: Ireland
Town: Ennis
Boat name: pac 22
Make: Halmatic
Length: 6m +
Engine: inboard
Join Date: Aug 2018
Posts: 118
mine is jet drive and is lower than stern drive transom and your right my measurement is deck to transom. Has the pac in pic been modified to meet regs, sorry for hijacking original post
__________________
mikehhogg is offline   Reply With Quote
Old 25 February 2020, 16:57   #7
Member
 
Country: UK - England
Town: Waterlooville
Boat name: Tickler
Make: Halmatic P22
Length: 6m +
Engine: Inboard Diesel 140HP
MMSI: 235115642
Join Date: Sep 2015
Posts: 1,200
RIBase
Quote:
Originally Posted by mikehhogg View Post
Has the pac in pic been modified to meet regs, sorry for hijacking original post
No, I don't believe it has.
__________________
GuyC is offline   Reply With Quote
Old 02 March 2020, 05:28   #8
Member
 
Country: UK - England
Town: Waterlooville
Boat name: Tickler
Make: Halmatic P22
Length: 6m +
Engine: Inboard Diesel 140HP
MMSI: 235115642
Join Date: Sep 2015
Posts: 1,200
RIBase
Quote:
Originally Posted by diver 1 View Post
I think its a common issue on many ribs
I wonder if it is as a result as a result of trying to get the outboard low enough to get the cavitation plate at the right height. It would be particularly difficult on boats where the deep vee wasn't truncated by a planing pad. I think RC's have a 'full' dep vee.

It sounds like an inner transom would be a sensible way to go. It would have to be sufficiently structural to withstand a head of water equal to its height as if the boat is swamped, it would be the inner transom that would be resisting the pressure before the elephants trunk or freeing ports could get rid of the water.

Whilst the well that Diver1 has fabricated seems to work I can imagine a surveyor might look at the volume of water the well could hold before it gets to deck level and say it is not big enough. I've done a similar thing when customers don't want a coaming in way of a weathertight door and we've created a well in front of the door. They are a reasonable distance above the waterline though.
__________________
GuyC is offline   Reply With Quote
Old 16 May 2020, 07:16   #9
Member
 
Country: UK - England
Town: Cambridge
Boat name: Drifting Away
Make: Ribcraft
Length: 6m +
Engine: Twin Evinrude 135's
Join Date: Feb 2020
Posts: 2
Thanks Diver1, that is the way i am going. Will update the thread once complete.
__________________
Boatserv is offline   Reply With Quote
Old 21 November 2020, 10:11   #10
Member
 
Country: UK - England
Town: Portsmouth
Boat name: None!
Length: no boat
Join Date: May 2018
Posts: 9
Hi Boatserv

Where did you get to with this mod you all coded now?

Thx Dave
__________________

__________________
Rib_Tickler is offline   Reply With Quote
Reply

Tags
rib

« Go Dabble | Top | - »
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




All times are GMT -5. The time now is 03:32.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.