Seaworthiness

[TeddyDiver]

Originally Posted by MikeJohns

Most likely a pressure hose test.

I think so too. The problem is that in the standard there's no definition for the test, only for 2,3 and 4. It's allmost like if someone claims a door is watertight (#1) no test is needed

[sloopelan]

Hello All - have downsized to a Bayfield 29 (from Countess 37) and have been talking on our group about "pitch-pole" and if a compression post at the forward bulkhead would help or will it just transfer the damage to the hull. Bayfields are good tough boats but the hull is built in 2 halves. The mast is keel stepped so the talk is simply about the deck. The compression post would meet the hull ahead of the balast so my concern is downward load splitting the hull halves. Your input would be appreciated.

[marshmat]

But what will a pressure hose test tell us, though? I can think of more than a few ways to build a sliding patio door that passes a hose stream test, and passes for watertightness under suction on the interior side with a spray rack outside. And most of those would still blow out if they were asked to hold back water pressure at 6 foot depth, as is the case for the sliding doors on those boats if they are expected to keep the deckhouse watertight in a capsize.

At the very least, hatches or doors that are essential to the integrity of the craft ought to be able to withstand the water pressure they would be subjected to in a capsize. That's not too difficult to test with a steel chamber, spray racks, and air compressors.

[TeddyDiver]

Originally Posted by marshmat

At the very least, hatches or doors that are essential to the integrity of the craft ought to be able to withstand the water pressure they would be subjected to in a capsize. That's not too difficult to test with a steel chamber, spray racks, and air compressors.

Maybe thats something the manufacturers had hard time to live with so I think I will make my own hatches and doors and do "jumpin with the kids" test and give a finger to ISO standards

[Guillermo]

sloopelan,
I think your question doesn't belong to this thread, so you'll get few responses here. You'd rather use the Boat Design sub-forum.

Anyway: I do not understand why do you want a compression post at the forward bulkhead at all . If there's a bulkhead, that's all you need to transfer loads at that point. Having said this, even if a hull is built in two halves, there should be a very strong reinforcement at the jointure because of the many layers probably used to joining the halves together. And you can always spread the compression loads by using adequate footage for the post. But as I do not know the Bayfield 29, I think it would be better if you put your question at the Boat Design sub-forum, as said before.

Cheers.

[julleras]

Guillermo:

Should the Cabin volume be taken into consideration in calculating the limit of positive stability? Or just the hull?

Un saludo (for Americans: Greetings),

[Guillermo]

Hola Juan!
Yes, cabin volume should be taken for the stability calculations if structurally strong to resist a rolling over without being damaged and is as well watertight (category 1 under the ISO rules).

But if there are big sliding doors, it has to be suspected they do not comply with watertightness nor structural requirements. I know of a very well known brand of excellent motorsilers which having sliding doors at the sides of the wheelhouse, do not get category A under the RCD, but only B (confirmed by the manufacturer).

I have been thoroughly searching for watertight both sliding and structurally sound doors as to resist a knock down for small yachts and I have found nothing. The only I've found are for big vessels and are pretty heavy.

I think some manufacturers out there are not correctly categorizing their sailboats when they use those big weak sliding doors.

Cheers.

[Guest62110524]

class b,c, CE, RECREATIONAL,
does anyboby have any idea of the rule, wl to weather deck(freeboard)
thanks so muchely

[Guillermo]

Yes, you have the minumun freeboards for the different categories at ISO 12217. PM me to the office (wednesday) if I can be of further help.

All the best.

[Guest62110524]

Originally Posted by Guillermo

Yes, you have the minumun freeboards for the different categories at ISO 12217. PM me to the office (wednesday) if I can be of further help.

All the best.

ok will ring,

[Guest62110524]

ok will ring you

[fcfc]

Originally Posted by Guillermo

.......
But if there are big sliding doors, it has to be suspected they do not comply with watertightness nor structural requirements. I know of a very well known brand of excellent motorsilers which having sliding doors at the sides of the wheelhouse, do not get category A under the RCD, but only B (confirmed by the manufacturer).
.....

I am not sure. I think it is more a problem of downflooding angle definition than door structural and watertightness. Given the reputation of the manufacturer, and the price of the motorsailers, I suspect the doors are already watertight as per iso 12216 and are structurally strong enough.

I fear the side doors have to be open for downflooding test as you cannot put on them a label "keep shut under way" : they are the main cabin entrance. There is also in 12217 a angle phi DH angle of downflooding main access hatch to main outside helm station. This angle is defined, but I have not found were it is used

I suspect the cure would be either a floodable pilothouse, kind a covered central cockpit, with watertightness and draining. Or a central rear door on the pilothouse, wich would be the main access to outside helm, and would allow the side doors labeled "keep shut under way".

[Guillermo]

Yes fcfc. It can be the way you describe, rather a downflooding angle issue because the access doors cannot be considered closed at all moments. (Although then we should not consider permanently closed any kind of main access to the cabin, thus invalidating most of the said able to resist a 180º capsize sailing boats)

woosh:
please do not ring, as I'm not going to be at the office all the time. Send me an e-mail instead.

Best.

[Guest62110524]

guillermo
its actually 13.4 wl, 13.77 huill length yes motorboat, is it 1/17 wl, on class b?
looks like class c then
I sent mail in reply
THERE ARE SOME EXCELLENT WINDOW DOORS IN HOLLAND also freeman in USA, I will try search for you in Holland as I look same for us
Mike, Maclears AGYNTYRE, would be the one you think of?

[TeddyDiver]

Originally Posted by whoosh

class b,c, CE, RECREATIONAL,
does anyboby have any idea of the rule,

Any help from this http://eur-lex.europa.eu/LexUriServ/...94L0025:EN:NOT

and the standards http://www.iso.org/iso/iso_catalogue...CS1=47&ICS2=80
and the same in diff order http://www.iso.org/iso/iso_catalogue...m?commid=54258