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Old 08-17-2012, 11:22 AM   #81
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Originally Posted by Larmex99 View Post
I can only guess based on a short period when my fins had to be pinned to straight while I repaired a bolt housing on the arm actuator. I noticed that my fuel use increased 5-10% without the fins being active. Interesting to note as well that the inactive fins still helped to prevent roll although less than when they were active. A friend once told me that once you have stabilizers you will never want a boat without them. He was correct.
Thanks for the response. My fuel flow meter is analog, so it is hard for me to detect small changes, but your experience confirms what I suspected was the case. Makes sense I suppose, since trawler hulls are generally not designed to be efficient with heel angle induced like sailboat hulls are. Robert Beebe thought that some form of stabilization was essential for any vessel that navigates in blue water. Many boats that are called trawlers are not designed/intended/used for that duty, so probably don't need them, but for ocean work I have to agree with Mr. Beebe. Plus it's nice to arrive at your destination relaxed rather than having felt like you just went through the spin cycle at the laundromat.
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Old 08-17-2012, 12:41 PM   #82
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NAIAD maintain that, except in dead calm conditions, active fin stabilizers actually INCREASE speed through water somewhat. They say stabilizers reduce the wetted surface area of the hull relative to what it would be if rolling and that around a 0.5kt gain is not unusual. In dead flat conditions, a 0.5kt penalty.
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Old 08-18-2012, 05:05 PM   #83
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Mark, I was told by a Bristol trawler in CT that a stay sail kept him from rolling too much. I have the same mast and boom he has but no sail. Should I just call t he local rigger and say fix me up with everything, and is it really worth it?
Steve
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Old 08-19-2012, 05:13 PM   #84
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Just to add our 2 cents-we have the ABT Trac, 9.5 sqft on a 58', 50 ton boat. They are are great, and as noted, once you have them, you will not want to go without. Very reliable, ABT has the ability to work when the boat is at rest, but we did not see the need to upgrade our system. One note on our installation compared to the Bayliner, we have twin keels, one for each shaft, so we can sit on the bottom without worying about damage to the fins. They do not extend beyond the waterline beam so no real damage issues there. With Mitsubishi not having any similar installations, and the fins, from any vendor, having a long solid history in your hull, I would be a bit leery over the gyro. I would have to be really convinced of a substantial performance difference over active fins to consider the gyro.
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Old 08-20-2012, 02:45 AM   #85
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For your choice

I thinking your idea of gyro it is a good choice because :
-you can't put a mast on your boat : no sails , no paravanes
- the Naļads always make a bigger drag and more consumption
- the gyro could work at anchor
- the gyro can't be hit by something , drag a net or rope
We have a hull with hard chine we have a great stability curve...and we roll with a very short period
Last year we added two "bilges" keels around 14' long and 10" wide, a 8m mast with
18 sqm main sail full battens ...it dampen , a litle the roll .(and we have already two sideboards !!)
On Setsail they show some films taken in bad weather and the ride looks good with over sized Naļad ....but unfortunately also over sized for my bank account
But gyro look good, if you can get 'background'.
On one boat we had Naļads it work well, but with all problems listed above : drag,consomption, possible 'trap' for roppe ,,net even bottom of a river side ...
If you choose Gyro please let know to us what happen , you are like a 'cobaye'
(side boards)
Dérives - Le blog de long-cours
(mast)
Māture - Le blog de long-cours
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Old 08-20-2012, 03:40 AM   #86
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I'm coming in at the end of this long thread, so these points may well have already been made.

Fins are availble for at rest or anchored conditions, such as Tracs.

Gyros are becoming more and more popular in the UK.

If thinking about locating a gyro in the lazarette, my concerns would be twofold. The first would be the twisting moment on the hull when in operation, and the second would be if the lazarette is the best position for the gyro. I've only ever seen them in apprx mid-ships positions.

That's my two cents-worth!

Cheers - Piers
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Old 08-20-2012, 04:13 PM   #87
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Quote:
Originally Posted by stevensibs View Post
Mark, I was told by a Bristol trawler in CT that a stay sail kept him from rolling too much. I have the same mast and boom he has but no sail. Should I just call t he local rigger and say fix me up with everything, and is it really worth it?
Steve

I have talked to a number of GB owners who have steady sails. They say they do a good job on a mooring or at anchor of keeping the boat headed into the wind and so usually the waves which reduces rolling.

But almost all of them say a steady sail of the size that can be carried on a GB's stock mast and boom is too small to to much of anything in the way of damping roll underway. And since the mast and stays are not made to take high sideloads, using the sail in stronger winds can, and has, resulted in the mast breaking (wood) or bending (aluminum) or breaking the stay securing hardware.

We considered the idea of adding a steady sail to our boat at one time, not because we find rolling a problem or even all that uncomfortable but just because it sounded like an interesting idea. But after talking to owners who have them we decided against it. On a mooring or at anchor in windy weather if the boat hunts enough to induce a rolling motion on top of the pitching motion we put out a stern anchor which I think does a better job than a steady sail anyway. And with the sail area that we would carry damping a roll underway would be almost unnoticeable and we could easily over-stress our mast and stays.
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Old 08-21-2012, 03:14 AM   #88
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You are right for

Quote:
Originally Posted by Marin View Post
I have talked to a number of GB owners who have steady sails. They say they do a good job on a mooring or at anchor of keeping the boat headed into the wind and so usually the waves which reduces rolling.

But almost all of them say a steady sail of the size that can be carried on a GB's stock mast and boom is too small to to much of anything in the way of damping roll underway. And since the mast and stays are not made to take high sideloads, using the sail in stronger winds can, and has, resulted in the mast breaking (wood) or bending (aluminum) or breaking the stay securing hardware.

We considered the idea of adding a steady sail to our boat at one time, not because we find rolling a problem or even all that uncomfortable but just because it sounded like an interesting idea. But after talking to owners who have them we decided against it. On a mooring or at anchor in windy weather if the boat hunts enough to induce a rolling motion on top of the pitching motion we put out a stern anchor which I think does a better job than a steady sail anyway. And with the sail area that we would carry damping a roll underway would be almost unnoticeable and we could easily over-stress our mast and stays.
the size of the mast ! all the fitting must be strong enough (or stronger than necessary ) pilar, chain plate, section of the mast, diameter of the rigging and also the sail must be in heavy clooth , because our boat are heavy and generally we use sail in bad weather .
Also the sail must have some reefing system .
I have colleague owner of GB and also they say : the main problem is the roll (GB50 GB42 GB48 ) and they all fit stab
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Old 08-25-2012, 03:44 AM   #89
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Have you considered the Seakeeper gyro? They have numerous examples on their website and only use about 2kW of power, thus much more efficient than the Mitsubishi

Seakeeper Website

The installation seems pretty compact too as per this Grand Banks example

http://www.seakeeper.com/images/inst...randbanks2.jpg
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