Sun Fast 3600 keel cracks

[beepee]

Hi all - very new member here - about to take delivery of a 2018 SF 3600 and hoping someone might be able to help me with investigative work on keel cracks. I've done some fairly exhaustive searching and haven't turned up anything substantial or systemic with Sun Fast 3600 problems anywhere.  I was thinking of emailing Jeanneau directly, but perhaps this knowledgable forum has some ideas as my French would likely lead to many fits of laughter...and little help :-)

Pics attached - a recent survey has identified a 'U' (more like the bottom and two sides of a square than a real 'U') crack about 12 inches from the leading edge at the top close to where the keel joins the hull. The cracks are symmetrical on both sides.

From the research I did (not specific to SF 3600s) it seems like it could be the fairing cracking around an access panel to the keel bolts or the fairing around a keel sump. I'm not familiar enough with 3600 construction to know whether they have access panels or sumps at all. Doesn't seem like it could have been from a hard grounding as I would have thought a grounding would be more cracking/separation at the hull/keel join rather than this weird U shape crack.

The rest of the boat seems in very good shape - which is to be expected with only a couple of years since production I suppose - it has been kept in warm saltwater since being launched.

Any ideas on the cracks? Thanks for any and all guidance, advice or counsel. Excited to be part of the Jeanneau family!

[MalcolmP]

I am not familiar with the 3600, but agree it looks like a possible sump box. On earlier Sun Odyssey's these were faired in and could often be seen. On newer SO's they tend to have a reciprocal hole in the keel top to avoid this. 

You could ask on the Sun Fast group on Facebook as there are several SF3600 owners there

www.facebook.com/groups/1539609846076259/

[fimacca]

It is the right place for a sump box. the right shape as well.
Does it correlate with the sump inside ?
There is a Jeanneau SO 45 next to me in the yard and I can see the sump box is much more visible than mine.
if it follows the line of the box, it is likely ok.

you can see the SO behind mine in the pic here with sanded keel and sump exposed.

Surely the surveyor gave you an account of what they thought?
Any damage around the keel, edges or bulb ?

[MalcolmP]

Also if you lightly tap that area, if it is the sump box, it will sound hollow

[beepee]

Thanks for the quick replies/ideas everyone! It's a Jeanneau dealer that I'm buying the boat from - strange that they as well as the marine surveyor don't know what it is...  The boat is not local to me so I can't go inspect it myself, but have asked them to pull the floorboards and have a look from inside to see if there is a sump box there and also to tap the outside to see if it sounds hollow compared to the rest of the keel. If it is indeed a keel sump, I assume the cracking is likely just some shrinkage of the fairing - likely no cause for alarm. The bulb of the keel has no evidence of any grounding and there is no separation of the keel from the hull - I don't think there are any grounding issues.

Malcolm - I've successfully avoided having a Facebook account for more than a decade...but I might have to bite the bullet to get access to that Sun Fast group you linked...hmmmm....join the evil empire and get my keel sump question answered....or, continue to live off the social grid and live in fear that the keel will just drop off during the Transpac...  :-) 

Thanks again!

[MalcolmP]

Feb 21, 2021 16:23:00 GMT beepee said:

.....Malcolm - I've successfully avoided having a Facebook account for more than a decade...but I might have to bite the bullet to get access to that Sun Fast group you linked...hmmmm....join the evil empire and get my keel sump question answered....or, continue to live off the social grid and live in fear that the keel will just drop off during the Transpac...  :-) 

Thanks again!

I too have lots of reservations on FB, glad Australia is trying to stand up to them. I only use it for Jeanneau things, not personal.

Suggest you contact Nigel Colley at Sea Ventures. Nigel knows all the Sun Fasts very well and has successfully raced all models long distance off shore. Sure he will be happy to give you his views if you email him the photos.
www.sea-ventures.co.uk

[beepee]

Copy that - thank you Malcolm!

[beepee]

Quick follow up Malcom - Nigel was super helpful, responded immediately and even included drawings, incredible!  For those of you curious about the resolution/explanation, this is what Nigel had to say:

"This U Shape cracking is absolutely nothing to be concerned about. There is a cut out in the top of the keel of the same shape (see attached keel drawing for the L shape keel, but the straight keel has the same cut out.

The cut out is there to accommodate the bilge sump, which is part of the hull mould. The gap between the hull bilge sump and keel cut out is filled with gunk and sealant, and the keel will move a little in relation to the hull, so the seal opens up. The sealant just needs routing out, let ot dry and the reseal and fair. I did this every winter on my 3600.

The 3600 is a great boat and you will have lots of fun with her."
SF3600 L Keel drawing.pdf (136.23 KB)

[MalcolmP]

Excellent, reassuring as Nigel really knows his stuff and quite a demon in the single handed and double handed events. Glad he answered your concerns, look forward to hearing more when you get her and your prep for the Transpac.

[fimacca]

sack that surveyor if he didn't know what a Jeanneau sump box is !

[beepee]

Yeah..kinda thought that too :-)