Naval A / Boat Builder/s please comment

[Zozza 336]

Okay, I have basically stripped out the interior of my GRP 28 footer.
The guy I have hired to do the donkey work, while not a qualified boat builder, has worked on boats for decades, but he admits a bit of guidance required now.

If you look at the photo, which is looking for'ard from aft, he is proposing an idea to replace the four main bulkheads with crescent moon shaped bulkheads to open up the interior, plus a series of evenly spaced ring-frames in the main cabin.  They would all be tabbed, filleted and glassed in of course.  Those four current original main bulkheads are not inserted like I propose, they are just glassed in hard up against the hull - no fillet or tabbing.

To be borne in mind is the current main bulkheads would have helped spread the load of the bermudan rigged deck stepped mast. The new junk rigged mast will go further forward, and be keel stepped with the appropriate mast step and mast partners and ring frames constructed to take the loads (note - there are no stays with a junk rig mast).  I have put a red mark where the new mast will be stepped.

I cannot consultant the man that designed this boat, an Englishman by the name of Kim Holman, as he died some time ago, so asking anyone of suitably qualified NA or boatbuilders on this forum with enough experience and wisdom to advise if a series of evenly spaced ring frames instead of your classic bulkheads - will be adequate of strength to ensure this boat's strength is not going to be compromised, while having the effect of "opening up" the interior a bit.

Thanks in advance anyone with any tips.
 

[K4309 395]

Do you want to sail it to Argentina or Arkles Bay?

As in, Cat 1 or Gulf Cruising. Will make a difference to how diligent you (or anyone giving advice) need to be, and consequently how robust the design work and physical work needs to be.

[Zozza 336]

2 hours ago, K4309 said:

Do you want to sail it to Argentina or Arkles Bay?

As in, Cat 1 or Gulf Cruising. Will make a difference to how diligent you (or anyone giving advice) need to be, and consequently how robust the design work and physical work needs to be.

Possible round NZ, possible Offshore to the Islands and beyond, yes.

[Psyche 775]

The advice here is free, the quality may vary, if I were you I'd contact a good local NA and pay for advice based on calculations and experience especially since your life depends on it. The localised loads from an unstayed mast are considerable, and the lack of bulkheads is concerning to say the least. Half bulkheads do very little, ring frames may be helpful or not....

[aardvarkash10 1,085]

Free advice is worth as much as you pay for it.

I'm with psyche.  Consult a qualified MA.  It will certainly help to have their documentation at Cat 1 time, as well as insurance time and sale time.

You'll sleep better when you are 856nm offshore as well.

[Zozza 336]

Thanks fellas. Understood

[LBD 176]

OOOoooo ....This is gunna be expensive.... mind you that is only an estimate!

[Psyche 775]

Try Brett Bakewell White,  shouldnt be too expensive and whatever you pay now, it will be cheap in the long run! 

[Zozza 336]

26 minutes ago, Psyche said:

Try Brett Bakewell White,  shouldnt be too expensive and whatever you pay now, it will be cheap in the long run! 

I was also thinking Richard Edlin.... he is up North too, which is where my boat is

[Frank 161]

Pretty Much what others have said and sailing characteristics will need analysis with such a significant sail plan/rig change. (Balance and Fwd Buoyancy comes to mind.) There is a junk rigged Raven 26 in my local mooring field and it looks fine although I have never seen it sailed. As a front load before contacting the Naval Architect  see if you can get a copy of the lines drawing, in my experience its usually the first thing they ask for. My wifes uncle and aunt did a 7 year circumnavigation in a Junk Rigged 31 footer , went up to Japan , Russia, the Aleutians, Alaska etc, wrote a book and all.

[waikiore 462]

Ring frames are good, though in a glass hull you cant treat them in isolation -ie they need to be connected as well not just to the skin , thats where multi diagonal trad kiwi boatbuilding has some not always recognised benefits.

Plus one for Brett Bakewell White

[Zozza 336]

7 hours ago, Frank said:

Pretty Much what others have said and sailing characteristics will need analysis with such a significant sail plan/rig change. (Balance and Fwd Buoyancy comes to mind.) There is a junk rigged Raven 26 in my local mooring field and it looks fine although I have never seen it sailed. As a front load before contacting the Naval Architect  see if you can get a copy of the lines drawing, in my experience its usually the first thing they ask for. My wifes uncle and aunt did a 7 year circumnavigation in a Junk Rigged 31 footer , went up to Japan , Russia, the Aleutians, Alaska etc, wrote a book and all.

Yes I know both boats.  'Fantail' is the Raven, and 'Shantung' is your wife's uncle and aunt boat.

To be clear - there is no issue with the junk rig, it is just assessing the best method to reattach bulkheads or at least peruse options to perhaps slightly open up the interior without compromising the integity of the hull.  

Cheers

[Zozza 336]

On 1/12/2024 at 4:47 PM, LBD said:

OOOoooo ....This is gunna be expensive.... mind you that is only an estimate!

You know, I have been thinking about your post LBD - and it did give me a chuckle.

However.... I have been lucky enough to be born in a western nation, I have worked my butt off for 40 years, I have no children (none that I know of 😆 ), no dependents (though I do help look after my elderly parents), no wifey (not through trying but sailing dreams and landlubber Kiwi gals not a good mix!) and a couple months back I went to a funeral for a lady boss of mine for many years, who retired some years ago now.  During the funeral, her husband died of a heart attack during the funeral service - he was 15 feet in front of me.  It was surreal.  It really hammered home the 'Captain Obvious' observation that - life really is short and I don't want to be lyingon my kick the bucket bed and be regretting I never did what I really wanted to do.

I have always wanted to own a Twister and even considered importing one from the UK if not going and living over there to make it happen (got an EU passport and all that) but then Brexit happened and scuppered that idea.

To sum up - big $$ in this refit, bu I am the type of person that when I want to do something I do whatever it takes to make it happen even if it leaves me poor of wallet at the end of it - and it certainly will. 

When finished this won't be just the best old GRP boat of its size and design in NZ (a purely bias point of view of course!), but it will be my home for decades ahead - hope good health and time and chance permitting of course.

But - generally, if you are not psychotic like me that when you start a project you must finish it come what may, I would do everything to put the 'normal' person off going down this path.  You will be light in wallet, and high in emotional stress during the ups and downs of huge refit.....well, really, it is a rebuild.

Cheers

[Black Panther 1,745]

That all sounds perfectly reasonable. 

[LBD 176]

5 hours ago, Zozza said:

" not psychotic like me"..... that when you start a project you must finish it come what may, I would do everything to put the 'normal' person off going down this path.  You will be light in wallet, and high in emotional stress during the ups and downs of huge refit.....well, really, it is a rebuild.

 

Psychotic?.......Others need to be the judge of that...  

But you are right about finishing a project, I pretty much walked away from one twenty odd years ago, that I had put a few years into. It has bothered me ever since, probably because of the dreams that went with it at the time. And as for $.. I am the same, do not cut corners, "do it once do it right".

Good luck with the dream project. 

[Guest 129]

I know the symptoms well, only to recover on launch. Only took ten years, but I was multitasking.

I used  Tom McNaughtons online design service and David Gerr's Elements of boat strength. I still have David Gerrs book if you would like to borrow it.

http://www.macnaughtongroup.com/designs.htm

Mainly I used DG.

PM me or Brent has my number.