Stabilizers Grand Banks Classic

[BlueSkies46]

Hello Grand Bank Owners,
I have a 1987 Grand Banks 46 Classic non stabilized. I am wondering if anyone has installed Stabilizers on their boats and what type. I am looking at Bilge Keels. I have looked at the Gyros and they will not work for me do too price and Location under the main cabin mattress and Hight restrictions. Looking for something that will just cut down on the roll at anchor and Underway.

 

[Papas]

I have a 2001 GB46 CL and just got through investigating various stabilization options incl. Humphree and CMC Waveless, Naiad, and ABT. CMC appeared to be the best option - esp. if zero speed/anchorage stabilization is desired). Install costs were just too high for me (estimate came in over $100K). Several have suggested hydraulic, but since I would need to add pumps, lines, etc. (which result in more loss of ER space relative to the CMC's), the cost estimate ended up being comparable to electric.

I previously inquired about any GB's w/ Paravanes, but others didn't feel it would be practical given the additional reinforcing support structures (cabin structure, mast supports, poles, etc.) would likely end up being cost prohibitive.

If others have identified more cost-effective stabilization for GB's (besides buy a boat already equipped ), I'd be interested in hearing more too!

 

[Mambo42]

I don't have a GB, but a Defever 49, which had bilge keels, but was still rolling like a drunk chicken in a port, marina, on anchor and at sea. So the bilge keels had to go.
Gyros were not for me either and unfortunately other than flopper stoppers there is not really a cheap solution.
I installed electric fins, CMC waveless stab 25 (20 is the smallest) and have been happy ever since. We are steady at all speeds, our comfort increased with 1000 % and we will never ever buy another boat that is not stabilized at all speeds (also zero speed).
It is an investment, it is expensive, but if you use your boat a lot and you want stability at anchor, don't have a lot of space available and want to be able to run them off the battery, I can highly recommend CMC. We have them on 24 hrs per day, means they are always ready to intervene, but as long as you don't roll they don't use any electricity at all.
I know that some hydraulic stabilizer companies now also started looking into offering a modification so that those stabilizers can work at zero speed, but hydraulics are just to slow to come close to the efficiency of an electric stabilizer fin.
To give you an idea of the space needed for installation inside the boat. The motor sticks about 10 cm out on the inside of the hull, that is all.

 

[Papas]

FYI - the CMC Stab 20 is what would be appropriate for the GB46 (per CMC / my investigation).

A friend has them on his 55' navigator and loves them too. Space, zero speed, and overall simplicity / maintainability was why they topped my list if I ever change my mind and accept the cost.

Electric fins will consume more battery at anchor as they have to move significantly more than when underway. It seemed to me that unless one has a large bank (e.g. 1000ah) of Lithium where state of discharge can go well below 50% w/out concern, that generator usage would be necessary to make it through the night in a rough anchorage.

@Mambo42 - what size battery bank (and type) do you have, and what has your experience been with overnight energy consumption (average and under more trying conditions)?

 

[ksanders]

I installed bilge keels on my Bayliner 4788 and they dramatically changed the boat for the better.

But...

My bilge keels are 12" wide and 24' long.

A bilge keel works by making the boat's rolling motion move water weight. The larger the better results.

In another thread here on TF, a Naval Architect explained that Bilge keeps do not change the roll period. They reduce the roll angle, and since the roll period stays the same the roll velocity, and acceleration is reduced.