1979 Thunderbird Formula Leaning to the side

[welovetoboat]

I have a 1979 Thunderbird Formula 18' Had it out twice since got it. It is leaning to the passenger side. We had approx same amount of weight on each side. Moved one person to the drivers side and it leveled out. Now I have 3 people on one side and one person on the other side. So: 195 pounds on the leaning side and 565 pounds on the other side just to level the boat out. What could be the cause of this? I have had 3 other boats and NONE of them did this. I am baffled! ANY help is appreciated.

 

[Splat]

Re: 1979 Thunderbird Formula Leaning to the side

Is the list only present underpower or is it present floating at rest?

If only underpower it could be a torq issue.

If happening at rest its a weight probllem. Could be as simple as weight distribution, or muck more serious like water logged foam.

When you pulll the boat out of the water and pull the plug does it constantly drip water?

Bill

 

[P 0 P E Y E]

Re: 1979 Thunderbird Formula Leaning to the side

We once had a boat that used to inexplicably capsize. A 20 foot Maxim with a big yamaha...a fast boat that performed well but a stinker of a sinker.

Usually after a rainy night on it's mooring the fugging boat would go belly up.
The bilge pump was new, heck we put two separate pumps in and still found the boat upside down after waves and Storm conditions on the mooring.

We hauled the boat, used a air pump to put some pressure in the bilge and found no leaks externally just the access to the battery well and around the cable boot.

After giving up we removed the cockpit sole under the console and forward of the console and guess what we found?

When the boat was made, the weep holes on the ribs/bulk heads were not fully drilled through.

The left over splinters around the holes, combined with bilge funk and left over assembly debris made each weep hole act a perfect check valve.

As the bow was lifted and lowered in the wave, any rainwater in the aft bilge was being passed forward and being trapped by the "check valves"

You may have just a similar problem.

 

[welovetoboat]

Re: 1979 Thunderbird Formula Leaning to the side

Is the list only present underpower or is it present floating at rest?

If only underpower it could be a torq issue.

If happening at rest its a weight probllem. Could be as simple as weight distribution, or muck more serious like water logged foam.

When you pulll the boat out of the water and pull the plug does it constantly drip water?

Bill

The list is only present underpower. Sits perfect in the water when still. When we pull the plug not a drop of water comes out. Seems to be when pouring on the power this happens.

 

[Splat]

Re: 1979 Thunderbird Formula Leaning to the side

The list is only present underpower. Sits perfect in the water when still. When we pull the plug not a drop of water comes out. Seems to be when pouring on the power this happens.

Well there's the answer. The list is caused by torque or rotational forces on the boat. When the power is supplied to the propeller the prop spins in a clockwise direction. That rotational force is counteracted and an opposite force is placed on the boat causing it to list to port. This is normal, and more apparent on some boats.

A prop change may help with this, perhaps going to a high performance or stainless prop with less drag may produce better results. The other option here is to invest in a set of ADJUSTABLE/POWERED trim tabs such as those from Bennets.

Also for future reference keep your questions about responses here in the forums, not in private messages. This is what these forums are for, so everyone can gain some knowledge, and throw their .02 cents in. This is how we get good at this stuff.

Bill

 

[P 0 P E Y E]

Re: 1979 Thunderbird Formula Leaning to the side

My earlier post would most likely not apply to your question. Please excuse.

Do you have trim tabs?

Is there a depth sounder or any other transom mounted device that might be in the slip stream effecting attitude of the boat? A swim ladder or platform too low perhaps.

Is the hull sound and strong or might it have an irregularity or previous repair that could be throwing things off?

Is the drive unit plumb...(straight up and down, side to side?)

 

[welovetoboat]

Re: 1979 Thunderbird Formula Leaning to the side

Thanks for the info. I really appreciate the help! I can not tell you how much I have learned about boating in the forums!!!