Hello all, When I sailed my Nacra 5.2 this summer I noticed that the boat had a tendency to want to push the bow of the downwind hull into the water a lot. I usually had 2 people on the boat and sitting as far back as possible on the windward side. If I began flying a hull the opposite bow would begin to dive the higher the windward hull would go. It made for some sketchy sailing. I didn't want to pitchpole the thing and it felt like it would every time if I would let it.
My question is.... How can I prevent this next season? Is there to much or to little mast rake? Any other adjustments I can make?
I was so excited to get the boat and now I don't think its that much fun to sail with this happening. Non of my other Cats have been that way. Hope it can be fixed.
Looking forward to everyones feedback.
Thanks you in advance.
Nacra 5.2 hulls wanting to Dive
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Posted: Oct 11, 2014 - 09:55 AM
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Posted: Oct 11, 2014 - 11:12 AM
Put a little rake into the mast. That forces the centre of effort back off the bows. My 5.2 likes to be raked so the top of the mast is about at the daggers. Also the 5.2s do tend to dive a bit. Putting the bow on as far as the bridle is usually not an issue and doesn't slow you down.
Also a 5.2 is very hard to pitch pole the hulls are meant to cut though the water.
Edited by Wolfman on Oct 11, 2014 - 11:14 AM.
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Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
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Posted: Oct 11, 2014 - 03:56 PM
Do you have a leak, or is the tendency greater on one tack than the other?
If you have a bunch of water in one of the hulls it runs to the front & wants to drag a hull down. When we first got the N5.0 it seemed to want to bury the port hull right to the beam when pushed moderately hard. I pitchpoled it one day, when I thought the hull should have come back up.
Turned out the drain fitting,(not the plug) leaked badly & there was probably 3-4 gallons in the port hull after a day or two of sailing. Once the bow went down, even a little, that weight ended up right at the bow.
Changed the entire fitting, & now get zero water.
On that boat the mast is raked back a fair bit, & it really has to be driven hard to pitch. Those hulls can be constantly 1/2 submerged at the bow, especially 2 up. We deliberately move forward to keep them down when going upwind,(skeg hulls). It is not uncommon to see the bow go completely under in rougher conditions, but they come back up.
I use less rake on the 5.7, but those are bigger hulls.
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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
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Posted: Oct 12, 2014 - 07:32 AM
Any boat with a jib as oversized as the jib on the N5.2 will tend to do that, the H16 which also has an oversized jib is very prone to burying the leeward hull hence its reputation to pitchpole. Many boats with oversized jibs tend to have footstraps on the stern of each hull. FYI, technically, any jib that overlaps the mast is known as a Genoa:-
Definition:
The term Jib is the generic term for any of an assortment of headsails. The term genoa (or genny) refers to a type of jib that is larger than the 100% foretriangle, which is the triangular area formed by the point at which the stay intersects the mast, and deck or bowsprit, and the line where the mast intersects deck at the rail. Colloquially the term is sometimes used interchangeably with jib. A working jib is no larger than the 100% foretriangle. A genoa is larger, with the leech going past the mast and overlapping the mainsail. To maximize sail area, the foot of the sail is generally parallel and very close to the deck when close hauled.
As above, just check your hulls for water, then learn your boats limits by pushing it hard....
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Posted: Oct 15, 2014 - 01:23 PM
I'll have to dig into some gopro footage but I've buried the leeward hull over the front crossbeam multiple times and it has come back up. This was going upwind though. 5.2 hulls are pretty buoyant.
I had a slow motion pitch pole at the finish line this past season, I was hot on catching up to a boat at the finish and was running a little too hot and with too much sheet. Caught a puff and shift then got wet. Finished the race on my side. Possibly your situation (too hot) if you are flying a hull downwind. I haven't seen too many boats do "the wild thing" without a spinnaker, you might need to head down more when it is blowing out.
When I'm headed down and I catch a puff I can see both hulls start digging. I run a square top main now that sits a little higher than stock so I have a little more force up there pushing the bows down than I used to. Usually if I head down or sheet out a little the sketchyness settles down.
Also you can depower the jib or genoa as mentioned above (I like one syllable words) by playing with the jib cars and sheet. If you get some twist up at the top of the sail then you are spilling more air and depowering the sail. Very beneficial upwind in hairy stuff, technique used a lot on overpowered monohulls.
Edited by cezo823 on Oct 15, 2014 - 02:24 PM.
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Cesar (Cez) S.
Hobie 16 (had a few)
Nacra 5.2 "Hull Yeah"
Vectorworks XJ - A class (not named yet)
West Michigan (Grand Rapids/Holland Area)
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Posted: Oct 17, 2014 - 11:05 PM
Luck of mast rake on Nacra boats should not cause bows to dig in. This year on my N5.0 I have almost no mast rake and I don't see too much difference from last year when I had more. We constanly bury lee hull up to the front cross bar and last week even to the strap in 6ft waves and boat comes out with out pitch polling.
IMO:
Check for water.
Check the stifness of your boat by lifting one bow and observe if the boat twists. If the boat twists then when flying hull windward bow go up and leeward hull digs in.
Relax while sailing, those hulls pierce the water like hot knife throught the butter.
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Adam Bartos
Nacra 5.0
SolCat 18 (sold)
Lake Zurich, IL
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Posted: Oct 17, 2014 - 11:22 PM
On my Nacra 5.0 I have a jib that extends beyound the mast by almost 2 ft, foot of that jib is parrallel to the hulls and profile is baggy rather then a wing, just like genoa. I am just wondering if that jib belongs to that boat or it was changed from original at some point.
What is the profile of the jib on your Nacras 5.0's baggy or wing? Will I see a lot of change in performance if I change the jib to a "wing" profile?
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Adam Bartos
Nacra 5.0
SolCat 18 (sold)
Lake Zurich, IL
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Posted: Oct 18, 2014 - 11:58 AM
A 5.2 is a very different boat than the 5.0 or 5.7. The centre of effort on a 5.2 is much farther forward and the slip resistence is at the daggers, not back at the skegs. My 5.2 likes to run with the lee hull buried to the bridle and can handle being buried almost to the beam. Makes for a wet ride. I've found that a little mast rake makes a huge difference in how much dive you get. A little rake balances the sideslip resistence between the daggers and rudders. Consequently you may have to tuck the rudders a little farther towards or under the hulls to avoid serious whether helm. But generally you get better performance. Try raking the mast at various angles but no farther than the dagger boards. Small changes make a big difference with rake.
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Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
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Posted: Dec 04, 2014 - 10:29 PM
Lots of good information here. I'm excited to make some changes in 6 months when we get Liquid again. Minnesota is such a short season. I'm hoping that 2015 is my year for sailing the crap out of this boat.
Keep the input coming, I appreciate all of it. -
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Posted: Dec 07, 2014 - 01:43 PM
"Keep the input coming, I appreciate all of it. "
I think the above pretty much covered all the normal stuff you could encounter.
If its not leaking just trim the mast back.
You won't believe the difference an inch or two makes! In mast rake, that is... -
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Posted: Dec 07, 2014 - 07:09 PM
The guys at the cat-club called my P18-2 the "submarine" cause they are
known for digging in the leeward bow quiet hard. So was mine.
Trimmed the mast one hole aft at the stay-adjuster. That helped a little .
Then some-one told me to leave the main sheeted, and ease the jib-sheet
when the leeward bow digged in. That worked really well.
For me, the best way to find out how far I could submerse the lee bow
was pitch-poling the P18-2. Did it two times and try not to do it again.
What I learned was you can dig in a leeward hull much more then I felt
comfortable with. Halfway the bridle and the front beam is no problem.
Regards, André
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Tornado (80's Reg White)
Prindle 18-2 (sold)
Dart 16 (hired and hooked)
13 mtr steel cutter (sold)
Etap 22, unsinkable sailing pocket cruiser.
Amsterdam, the Netherlands
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