Owner modifications to mass production boats

[Nicky17000]

Dear Glenn,
thanks for offering your highly appreciated advice on this forum.
Mostly everyone ends up doing modifications or adding gear to more adapt their boats to their tastes\needs.
Here I was thinking(fantasizing) about possible modifications that DIRECTLY effect the behaviour of the boat. Well, the intention is to improve not ruin it.
My question is, to what extent one is allowed to mess about the standard configuration of a boat without causing harm?
Although this is a general open question, our boat is a Hunter 23.5 water ballast. Examples of things that go through my mind ;
Replacing the fixed jib-sheet blocks with adjustable car.
Adding another reef to the main, near the boom (intention is to flatten in a blow since it is designed with a big belly)
Constructing a skeg\stump in front of the centreboard and possibly going aft around opening(intention is to improve directional stability upwind in very short choppy waves)
Inventing some different uphaul for the (heavy) rudder blade
or something else that you suggest.
Thanks for bearing with me.

 

[ghen]

Nicky,

Repalcing the jib sheet blocks with an adjustable track is easy. Little can go wrong there. The largest risk is going through the core and keeping it from leaking and soaking up water. It is not uncommon to add a reef to a mainsail. Adding the skeg/stump gets tricky. Instead of going through that effort, try raising the board some in those conditions. Two things happen. The first is you move the Drive Center of the centerboard aft. This moves the Center of Lateral Plane of the underbody aft therefore reducing helm pressure. That should make it easier to steer. Also the board is now not so vertical so the hull cannot pivot around the boat as much. It is in effect making the "keel" longer for and aft. Actually a third thing happens. The Drive Center of the board also is raised vertically. That helps stop the boat from tripping over the board. This a common practice in dinghy sailing. That make the boat easier to steer. If you add the skeg\stump you must worry about the drag you will incur.

 

[sailingdog]

Dear Glenn,
thanks for offering your highly appreciated advice on this forum.
Mostly everyone ends up doing modifications or adding gear to more adapt their boats to their tastes\needs.
Here I was thinking(fantasizing) about possible modifications that DIRECTLY effect the behaviour of the boat. Well, the intention is to improve not ruin it.
My question is, to what extent one is allowed to mess about the standard configuration of a boat without causing harm?
Although this is a general open question, our boat is a Hunter 23.5 water ballast. Examples of things that go through my mind ;
Replacing the fixed jib-sheet blocks with adjustable car.

Garhauer makes a nice system for this, that is reasonably priced.

Adding another reef to the main, near the boom (intention is to flatten in a blow since it is designed with a big belly)

If you're trying to flatten the sail, without reducing sail area, a cunningham would make far more sense.

Constructing a skeg\stump in front of the centreboard and possibly going aft around opening(intention is to improve directional stability upwind in very short choppy waves)

This could also cause problems if you ground the boat or when you're trailering the boat. IIRC, the H23.5 is a trailerable boat.

Inventing some different uphaul for the (heavy) rudder blade
or something else that you suggest.
Thanks for bearing with me.

Could you add a block to increase your leverage on the rudder uphaul??

 

[ghen]

I forgot about the rudder question. You could add purchase by making a 4:1 block and tackle versus the existing 2:1. On the Hunter 25 I made a lever system. It seems to work pretty well. It is very powerful. Another try is make a strut off the back of the rudder so the angle of the lifting line is a greater negating need for more power. It would be potentially ugly but would function much like a "Dolphin Striker" on a bobstay. It would make lifting the rudder easier.