Hanna Tahiti

[CMcC]

Hi,
I've just bought a Hanna Tahiti, 35ft, steel. It's junk-rigged, single mast.

It's a lovely boat, but even in light seas it rolls more than I'd like it to when motoring. Haven't had the sail up yet and I'm hoping when I do it wont be quite so bad.

Anyone had or got a Tahiti with similar problems? Any solutions short of redesigning the entire keel? I'm wondering whether lighter, shorter aluminium masts, ketch rigged would change things, but I suspect the problem is all in the hull shape.

Any ideas?

CMcC

[dcstrng]

I’m sure someone far more knowledgeable will chime in soon enough; however, having the sail up will calm down almost any sailboat quite noticeably…

Who’s design is the steel…??? Weston Farmer did a multi-chine steel rendition of Hanna’s Tahiti, but I don’t recall it being 35 foot (although maybe with sprit…). In any case, the Hanna design was not noted for having form stability anywhere close to today’s super-sleds, so I’d guess you’ll enjoy her more with the sail up…

[clockwork orange]

I know a guy who built a Tahiti ketch to Hannas plans about 30 yrs ago with the intent of taking the family cruising,they sailed it out of the great lakes and got as far as Florida,i dont recall him saying anything about rolling but they couldnt take the excessive pitching and sold it.
Steve.

[GordMay]

Yes, I think you & Larry are right about the hull shape being conducive to rolling, with no steadying sail.

[anjou]

WHat is her design displacment and does she match that?

[barnakiel]

Well, it is in the design. All Archer-like designs roll like hell. But you bought other things with the boat that may compensate. Hanna Tahiti is a beautifull boat, with loads of living space per LOA.

Taller or heavier rig will change the characteristics of the rolling motion. Try motoring with some amount of the sail up (but if you have a junk rig then you might be better off trying out a s/h jib sail flown in place of the original sail).

You will not eliminate the roll, but you can lessen it.

b.

[CMcC]

Thanks for all that info. I'm sure you're right about the sail taking out some of the roll. I'll find out this weekend. The design was taken from a Tahiti, but altered to 35ft. It was home-built, but they made a really nice job and the hull is very fair. Anjou - I'm not sure of the displacement or ballast ratio. I have the specs, but not in front of me; I'll check that out. I believe Hanna played about with his Tahiti ballast until he got it right, ending up at around 32%, I think..

I bought it because I believed it would go anywhere safely. I have sailed it briefly on the test and I was amazed that it pointed, but we were in calm seas. I'm happy to modify ballast and even the rig if necessary - they seem to go better with more sail. Would having a ketch rig mean less or more roll than a single mast? Luckily, the builder is still in town, so I can get some details (mast weight, etc) from him.

Barnakiel, you're right about the rest of the boat - she's lovely. But can you explain that bit about a jib sail in place of the original sail, please?

I'd like to know whether what I've got is all I'll ever get, or whether the motion could be improved. So, if anyone out there has had any experience on one of these, or knows of any group dedicated to this type of boat, please let me know.

Colin

[Hampus]

No personal experience, but I like the Tahiti. A lot of them were ketches and I'm quite sure that with a ketch rig, possibly a shorter main mast and masts of aluminium you'd improve the characteristics. A heavier and taller mast will increase the roll angle but the rolls will be slower due to more inertia. A lighter, shorter rig will decrease the angle of roll, but the roll rate will be faster.

A ketch rig will give you more options with regard to sail combinations and possibly increase the value of the boat. Besides, and this is my personal opinnion, they look better with a ketch rig.



You have any pictures of your boat?

Oh! Think about a gaff rig, like the one in the picture! It's slightly more work, hoisting the main single handed but it's not really a problem. You'll also be able to increase the sail area even more and keep the masts quite short.

/Hampus

[barnakiel]

Originally Posted by CMcC

Barnakiel, you're right about the rest of the boat - she's lovely. But can you explain that bit about a jib sail in place of the original sail, please?

You said junk, thus no jib. You can have a s/h jib hoisted (e.g attached to the mast with a loose Spectra loop, and hoisted with a halyard). Then the tack can be tied at the foot of the mast and the clew tied out to make the sail flat. I do not think you can use a huge jib, depends on how much and at which point the mast can be loaded. Now such a sail may slow the motion somewhat.

Raising part of the junk sail may help too, but I have seen them rather flapping arround than hold the boat onto the air). This is why I say use a jib in place of the junk main.

You can influence the motion and quite a lot, by moving the center of the rig's weight - and this not only up and down but also fore and aft - in this respect converting to sloop/cutter or ketch would change the amount and how she rolls too. Remember you are altering the relative placement of the weights (rig vs. ballast) but also vs. the center of displacement.

It is hard to say how much it will make things 'better' as better is subjective - some like it quick (see the pretty nervous move of a cat) some like it slow (see a narrow deep long keeler).

I think if you like how the boat moves under sail then you can just live with how she rolls when powering without sails up - because most boats roll in more or less nasty way then.

b.

[42AFJ]

A friend owns and cruises a Tahiti ketch. Having sailed in calm conditions I could not comment. He says that she can roll a good bit. Then again our boat can roll just as bad. The shorter aspect would help. In regards to the design, both Farmer and Merritt Walker (tahiti rover) had steel plans.

[CMcC]

Thanks and keep 'em coming. It's good to know there are others with the same problem. I'll hoist the sail and see what happens.

I was attracted to the Junk after reading "Voyaging on a Small Income" by Annie Hill. Simple, easy to use and cheap to run. The guys who made the main on my boat said they did it for about US $200 of cloth. They built the mast by wrapping fiberglass around a hollow wooden core. It's probably heavier than aluminium stock. I have to admit, though, these boats do look better with a ketch rig. Blondie Hasler designed a great-looking junk schooner. I have a habit, however, of changing things I don't like, then finding I've made no difference at all. I'll proceed with caution.

I'll take pics and post them Monday.

Colin

[barnakiel]

In our marina there are two active junk rig boats. One of them has just changed the mast from a heavy alloy to a lighter alloy because he did not like how the spar "pulled" the boat's bow when rolling.

The sails do look like very easy to make, but this refers probably only to a very basic sail (still, can be done). We met a Brit lady sailor in the Azores who had them made in double PCV coated fabric. But the other of the boats in our marina has a state of the art junk sail and believe me the difference is obvious. Definitely a good sailmaker's job and at a price.

Then, there is also a steel boat looking like a Hanna Tahiti, or a clone, here, and this one is a ketch (marconi or bermuda). She looks very well but does not sail much. The for mast is pretty fore and there is a short bowsprit. The main looks like stepped in the cockpit aft of the cabin trunk.

If you can find a s/h mast that you can buy at a very good price to make the main mast, then it might be an option to convert to a ketch. The mizzen mast will be easier to make as you will probably find a good s/h dinghy mast that fits. But beware there is a cost to everything, and usually much higher than we guess.

If you are happy with how your boat sails, remember to calc and mark the center of SA and keep the ketch rig plan pretty flexible to avoid getting the boat of balance with the new rig.

b.