None of my S;NE ships have shields so I guess that from my perspective, the No Shields weapon trait would be fine. 
I imagine that those folks whose ships have shields as their primary protection will be a bit annoyed if it became a wepon trait tho...
How would the proposed weapon trait "No Hull Damage" work?

I never liked Ignore Shields. To me, it always seemed like a one-up trait, something you put on a ship only if you're facing ships that have shields. And I really don't like the thought of spending 1/2 my ships cost on shields, and you 100% ignore them with a single trait.
Piercing is fine to me, it already massively degrades the value of shields.

Personally, I think "piercing" gives enough of an "ignores shields" flavor, but I've never been one to tell people what they can or cannot do with their own Starmada settings.

If you wanted to have a weapon that cancels shields (abbreviated [xSh]?), I'd use an SU multiplier of x2.74.

I would say that I wante'd both!
And for all reasons said here. NHD can be very interesting for some settings (primary or energy  beams from starfire, for example), and IS is also used on some universes. And as already say, I don't feel it could be cheesy as there are two other défenses.
ECM can be reduced by scout, but there is still nothing that counteract, at least a bit, armor. I would think as a weapon that destroys two armor for each damage. That's just an idea to make all defense with a counter, but this is not as 'compulsory' as NHD.

Marc

Interesting,
How would these work?

<copy/paste from my supplement manual>
--------------------
Crippling Shot

    Starships can (broadly) target specific systems on an enemy ship. This tactic is most often used by raiders to cripple potential prey that they can't convince to surrender outright.

-A crippling shot can only be made at close or medium range.
-A crippling shot can target one of Weapons, ECM, Shields, or Thrust.
-A crippling shot suffers an additional -2 attack modifier.
-A crippling shot attacking a ship's engines (thrust) can only be made through the target's AA (4-8) arc.

Resolve the attack as normal. Any [5] not stopped by the target's shields does damage as per the Effects of Damage rules. If any of the attack dice rolled came up [6], mark off one box on the targeted system, regardless of the amount of [6]s that were rolled. Any additional [6]s that were rolled score damage as normal.

Example:
    A ship targets an enemy vessel's engines using a Crippling Shot.
After applying all modifiers, it rolls five attack dice, coming up with [2],[4],[5],
[6],[6]. The defending ship makes a shield roll and does not stop any hits.
Two of the three hits are applied as normal damage. Because at least one of
the attack dice was a [6], one hit is directly applied to the target's Thrust
system.
--------------------

I'm still creating the supplement material so I haven't playtested the rule yet. If it proves too effective I may make it so even a roll of [5] misses, or increase the modifier to -3, etc. The idea though is that a crippling shot can only knock off 1 box per attack, so you shouldn't be able to blow off a ship's engines in a single salvo. I should probably add something about weapon restrictions as well, so only direct-fire weapons can do it or some such.

Indeed, you could really play with it to create some interesting dynamics (ECM systems, for example, should be significantly harder to hit than engines).

It's actually not a weapon trait, it's simply an alternate type of attack you can make at any time. Most of the ships in my alternate universe are very small by most people's standards (25 hull would be a large ship, frigates are 5-8 hull). So by making this type of attack you're likely going to prolong the amount of time it takes to destroy a ship over a straightforward attack.

But, like I said, the rule hasn't been playtested yet, so it's all conjecture at the moment.

I was aiming for a more BFG-sized feel with mine (BFG had cruisers 8 HP, escorts had 1, BBs had 12) and I wanted to significantly restrict the weapons on the hulls so one-shotting is kept to a minimum. Cruisers are sitting around 250 points, escorts around 50, with most ships somewhere in between. Having said that I'm fairly unfamiliar with the Starmada system (I originally designed my game using my own system, but it was too clunky) so it may not work out as well in practise. I should really stop designing ships and go playtest more 

If I was doing a direct conversion of BFG ships I might be tempted to do that (especially with BFG escorts -they had ONE hit point!). Funny enough, I realised yesterday I forgot a weapon trait on one of my weapons.. which meant redoing my entire fleet and resulted in ships being 1-3 hull larger anyway. Funny, that.