that sort of moment myself but you could look at trim tabs or a hydrofoil stabilizer for the engine, sounds like in a cross swell it wants to corkscrew.

 Have a talk to Epic marine site sponsor. He'll have the right advice for you. 

 Keel won't make too much difference, it's more of a structural thing than handling on that size boat, I would avoid hydrofoils as I have seen them dig in in similar situations you are talking about, I would adjust your driving style maybe, trim engine up to lift the nose and when you feel it start to dig sometimes putting a bit of power on to lift the nose is better than backing off hope that helps 

Don't know a hyrofoil would be the answer may even make things worse.

Need more detail as to exactly what occured -

did the nose bury into the back of a swell ahead or was it coming down the swell?

What was motor trim at the time?

Speed (including relative to waves)?

add on pics?

westerbergs generally have a fairly flat hull particularly if they are an older model. This makes them a fairly stable boat particularly with a following sea. Deeper V hulls tend to be a bit more prone to broaching

first thing to do would be check your trim, nose up when coming home with a following or sideways sea

Sounds like its broaching in a following sea?

You may need stabilisers
wwww.boatcollar.com.au
or
even a hydrofoil on the leg of motor may fix it.

 Should get a pic up for a bit of scrutiny on the hull .. what was the swell / conditions like on the day was this it’s maiden voyage with you at the helm   

 North coast is spot on, a lot of Ali boats broach when surfing swell. Suggest when a bigger swell comes in or you feel like your starting to surf, back off on the power a little bit will solve the problem mostly.

Its probably more noticeable when your going over 3 mile or shallow reef where the swell stands up and has a steeper front face.

If its fitted with a hydrofoil then remove it asap, they give the stern lift and in a following sea it can be deadly.

As others have stated, trim the nose up and back off on the throttle, better to slip back up the face of a wave instead of ploughing ahead into the back of the one on front.

 Tilt up motor to lift the bow right up should help. My boat likes digging a trench when in a seaway but never wanted to broach. Tilting up makes the ride a bit more pleasant.

I think the best thing to do is to take a couple of good photos of your boat (from the stern and bow) and go to one or a couple of boat builders who support this site and gain there professional opinion on what is causing you to have so much excitement.

 thanks heaps to everyone ,will take a couple of pics and post them, 

 Try shifting weight from front to back also can make a big difference in a following sea.

 having owned a few old westerberg of that size I'd suggest you are going way to fast and motor trimmed right down.  And that's a horrible idea in following sea in any boat.  

I'm presuming you have a skippers ticket yourself?  If not I suggest you get it and you drive the boat yourself don't let idiots drive ( father in law or not) as it will wreck your motor,  the gear you just flooded and maybe cost you your life. 

Learn from mistakes but stand your ground.  If it's his boat etc. Then just don't go out in it 

feral totally agree

banjo id take that advice and follow it up asap

id also be checking how front heavy the boat was loaded ?? how much gear was in the nose ?? how far forward are the seats positioned ,?? with a bit of gear and 2 solid boys in the seats /front of the boat @ 5 metres that and the motor trimmed down even a little will get you in the wrong place quick enough in a following sea at speed

hezzy

As most have said.... driver take care.

Very hard to work out without much more info.
but. if the boat had a meter add to it, it may pay to have a look at where fuel tanks are (underfloor and too far forward ?/ fuel sloshing with no baffle)batteries etc are and general weight distribution is.

and FWIW :Hydrofoil ....not a fan at all.

Mate has an older deep v aluminium 6m based on the Kolyn/ Star looking hulls. It can take off left or right and breach even in mild chop in the Mandurah estuary, its ok if you pick it coming, but can be dangerous if someone or something weighty goes arse over resulting in all weight on one side. Don't have an answer other than being aware and briefing the crew on staying alert if it takes place.

 mate, this can happen to anyone in any boat. Good advice from the crew, no matter what boat you are in, you need to learn it's good and bad habits and drive to the conditions, just like on the road.

As for the father in law......if it's even conditions are a little bit Suss, I never let anyone else skipper, learnt my lesson one day out of Dampier when a mate punched the throttle in a swell on full lock!!!

The older Westerbergs could be scary when driven wrong and in my opinion they were prone to broaching without warning, particularly when in a confused sea and engine trimmed down.

As everyone else has said, slow down and trim up. If you are in a 5m runabout, there is going to be a fair bit of weight forward. If you are going flat out and trimmed in, this is only going to push the nose down which is asking for trouble.

If the boat is prone to broaching make sure the motor is trimmed out to lift the bow, travel on an slight angle to the following sea (not the exact same direction as the waves even if you have to tack back and forth) and slow down (don't let the Father in law drive in following seas if he won't listen).

May pay to check weight distribution as suggested moving it rearward where possible.  

 Massive thanks to everyone thats helped ,will be the only one driving the boat  from now on ,and if there is a following sea will trim the motor to suit ,always been a big fan of the tortuise and the hair ,so will get there in the end  , and  in one piece.

 There are very few times i'm on someone elses boat and i actually feel comfortable with the trim of the boat!!

The biggest dead give away is the trim from take off!!

Keep the bow down until she starts to plane!!

If the Skip doesnt even get that he is definately not going to understand how the boat rides/performs when tricky situations arise.

I get sarcastic on here becuase you get sick of people asking dumb questions that relate to safety instead of gaining self experience like old mate that asked the listing to one side question! Get you're ass out there and gain the experience. Use logic!!

Get on the flattish water if you have to (river maybe) and gain experience.

I know i will get the haters on here for speaking my mind but thats a forum.

Banjo100, My rant isn't aimed at you but you're issue sounds like a trim problem and thats purely experience and understanding how you're boat performs.

Keep clocking the hours up and observe, if you're really not confident in you're own boat go out with a fella that knows what he's doing and learn from him.

You've got to learn to drive to the conditions, Boats are just like cars. You dont drive in a straight line then all of a sudden the cars turns and nearly rolls. Its the same in the ocean. You have to be able to see whats coming and adjust. 

 question you dont have to answer if you want? do you have water in your hull when you get back to the ramp? do you carry alot of anchor chain? where is the fuel tank and how much fuel was in it,  often overlooked when extending a hull. there are many reasons a boat broaches, design, weight,displacement, driver error and so on but one thing is true it is a very scarey event,, if you are in the mandurah area one day feel free to drop in and have a chat best of luck Todd