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Old 03-27-2015, 11:07 AM   #13
ksanders
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City: SEWARD ALASKA
Vessel Name: DOS PECES
Vessel Model: BAYLINER 4788
Join Date: Feb 2011
Posts: 6,267
As a guy thats been considering stabilization for some time here are some issues I've identified with either fin or gyro stabilization.

Fins

The actual fins for our boat would be placed behind the forward head vanity and under the berth in the "bunk" stateroom. This would require dis assembly of these internal areas, and significant hull build up in these areas. This is an extremely labor intensive process.

The hydraulic pump would be located on one of the transmissions, and a 5 gallon hydraulic tank would be located in the engine space as well.

I was quoted $27K from Wesmar for the basic gyro and fins of a proper size to provide underway syabilization. For the advanced gyro and larger fins to provide at rest stabilization the parts cost rose to $39K. Wesmar has done several 4788 installations so they have allot of the engineering done for my boat.

As far as installation fins require significant specialized labor skills that I do not possess. The fiberglass layup at minimum would have to be outsourced. I could do the mechanical and electrical work myself. I'm estimating it would take a "season" to do the install by the time I do everything and get it all cleaned up.

Advantages of fins are that they do not require the generator to operate.

Disadvantages are that the specialized labor for the fiberglass work is not readily available in Seward Alaska.

Since I sometimes run my boat at a higher than displacement speed cruise, my performance would be impacted. The simple fact is that fins will add drag and at a higher power setting the drag needs to be accounted for.

SEAKEEPER GYRO

The Gyro unit would be located in the lazarette. As Pete indicated the best place would be where my generator currently is. On my boat the two main stringers run the length of the boat and would be a perfect place to bolt the gyro unit to.

Moving my generator and re-arranging my lazarette is something I could easily accomplish myself with my existing skill set.

Bolting in the gyro is also something I could accomplish myself. I would consult Seakeeper and probably have a set of brackets to fit my stringers made up. They also have the potential of bonding the unit and or the brackets to the stringers to help dissipate the loads.

I'm estimating that the lazarette re-arrangement would take me a week to do. Installing the gyro might take me another week but I think it would go much quicker than that if I had mounting hardware pre-fabricated.

Gyro advantages are that the thing works at anchor and while drift fishing.
Running the generator is a disadvantage. This disadvantage is mitigated by the fact that I have a brand new Northern Lights generator that is very quiet and designed for continuous operation.

Weight is a disadvantage of the gyro, but we need to remember that the fins are not without weight themselves. The weight of the fins is a few hundred pounds total but the weight is distributed better with the fins than the gyro.

This is interesting enough that I'm going to start studying the feasibility of fitting the gyro into my lazarette.


There has been allot of discussion in this thread about loads being applied to the boat. We need to keep in mind that these are not shock loads, they are loads that are applied to counteract wave action loads.

With fins for example, in an installation on my boat they have been successful with a 2'X2' backer being glassed into the hull beneath each fin with only one edge having a connection to an existing stringer, and that stringer not being one of the two "main" stringers on the boat.

The gyro the unit would be attached to the two main stringers and the loads would be applied to those stringers. Those stringers run the length of the boat and by nature would dissipate the loads into the hull areas which are attached the entire length.

The only worry I have with the gyro is to spread the loads applied to the stringers over as large an area as possible. If for example I had a mount (think engine mount here) fabricated then the force would all be applied to the mount creating large compression loads in a small area. If I was able to use a plate for example and spread that load over a 3' area of stringer then the loads per square inch would be much smaller.
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Kevin Sanders
Bayliner 4788 Dos Peces
Seward, Alaska - La Paz, Baja California Sur
https://maps.findmespot.com/s/XLJZ#history/assets
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