Lobster Boat - too much pitch and roll

I am not to sure you would want to be hitting up and down trim buttons at the same time you are turning the rudder and watching out for the doubledecker wave also

I don't believe thats what I said or intended to convey, (but with the way things are 'mooderated' round here - who can tell anyones real intent anyway! ), however - I understand maybe what I've said has been mis interpreted.

I said nothing whatever about operating trim tab buttons while steering, only that a rudder in large heeling moments effectively beconmes a large trim tab in it's effect.

That is - while heeled in a long roll moment round bilge boat - the rudder alters bow trim angle - which can have the opposite effect to what the helmsman intended with course corrections.

For example- burying the bow with rudder correction (by oversteering) - mistakenly believing it will alter course - may NOT be the desired result in a following sea, where a buried bow - might increase the chance of a broach situation.

What the heck - I'm not sure anyone will understand what I'm saying anyway.

No doubt someone else will likely want to mooderate it or misinterpret it anyway!.

I'll keep my opinions to myself in future- wouldn't want to risk upsetting anyones delicate political sensibilities any further.

Opinions are like ***holes - everyone has one!

Anyone wants mine has only to ring and ask - least what I think or say can't be altered by anyone else to change it's meaning without my permission - when I speak on the phone!

Cheers!

[JR-Shine]

You could also make the roof lighter by making a new one from foam core or honely comb. What is the current roof made from and how thick is it?

[Thunderhead19]

weight distribution must be playing a part here....fore and aft weight distribution! This boat is obviously broaching in a following sea, and getting weight out of the bow and moving it aft should help in addition to what has already been suggested.. It may actually be that you boat isn't HEAVY ENOUGH. She may not be sitting on her marks.

[cyclops]

Shorelinedesign. I did not cover one serious condition in the 3' to 4'waves. If you were to loose power or rudder control in the worst part of the tall wave. Do you feel the boat could really continue on to it's side ? Honest answer here. Is she that rolly?

[Guillermo]

Shorelinedesign,

I believe you should first check your boat's stability, through a proper stability test. It seems to be too much high weight in that canopy. If you have a too high CG, that can be dangerous, specially when in a following sea with waves of length equal (more or less) to the boat's length. A wave crest amidships significatively reduces stability.

Furthermore, sailing in a following sea with a small GM and long natural roll period, may easily induce a parametric rolling movement when waves steepness and encounter period are adecuate. May become really dangerous, and it is not an easy problem to solve by the only adition of appendages or other methods.

You should first check your boat's GM in sailing condition, correct whatever necessary to lower KG, and then change sailing direction and/or speed when in dangerous following seas. Other solutions only after that.

I suggest you to read the following:

http://www.rina.org.uk/rfiles/IMO/SLF48-4-8.pdf
http://www.uscg.mil/hq/g-m/nmc/imo/p...1/Msc0/707.pdf

[shorelinedesign]

Top is about 1/4" glass over fiber core. Not exceptionally heavy, but certainly not a bimini.

Boat is a bit heavier with new roof and sits a bit lower in the front - the wooden splash rails (right word?) now touch the water line - it dirves me crazy. I'm in denial about the roof - it was a lot of work.

Boat will toss you about in heavy following seas. Only once did it feel like it wanted to go over, but I cut back the throttle and it righted. Probably was going too fast.

I know nothing about testing the GM - and not even sure what it is. I'll read the links though.

This boat is mainly a put-put, she sounds nice with the 302 inboard, and likes to cruise at about 10 to 12 knots. I like it best just above idle, However, it will top out at 17 knots but lists to the port side. Does that tell anything?

[cyclops]

The good news is , full power causes a lean. In trailing waves it adds to your lean going down them. BUUTT!! It straightens up if you chop the power. All is not lost. --------------Take 1 of these pills each time you go out in her.--------Pick a trip that has NO possibility of 3' to 4' waves. -----Results will be immediate and positive.------- She is a good boat. You need to be more selective on weather reports. Fix the keel before rot kills her.

[Guillermo]

Originally Posted by shorelinedesign

I know nothing about testing the GM - and not even sure what it is. I'll read the links though.

Be careful: Lack of stability kills people!
In my country it would have been illegal to alter the lightship weight distribution, even for a small boat like yours.
You may perform a simple rolling period test instead of a full inclining experiment, just to have an idea about your boat's initial GM. See Stephen Ditmore's #79 entrance at the "Ethan Allen" thread, and others there.
Ask a reputable Naval Architect in your zone to advise you, if in doubt.
The name of the game here is: Your life

[JLL]

As your boat is single engine, you need to look how the rear end of the new keel will end and where, and if the stern tube will be enclosed in it or not. If you note when running that the boats turns slower than before, you must to consider to change the rudder to a slightly bigger one. Before that , I don´t consider a rudder change.