I think by hull he means ship class.
There should be a delete button at the bottom of the class design(f5) window, if you don't see it try clicking 'reduced height windows' under 'game parameters' on the main menu.
And to the OP, you should concentrate a lot of your starting production onto factories and automines, even convert maybe half of your starting mines from earth into automines, then use freighters to move the mines and a mass driver onto planets with good mineral availability and reserves.
At the start of the game the most important thing is finding a few planets with high availiability for many different minerals to bulk up yours reserves. In order of importance at the start of the game you'll need heaps of Duranium, corundium, then tritanium and vendarite in order to keep churning out mines and factories constantly which will help your production in the long run.
Also of concern at the start is Wealth and Fuel reserves, income basically comes from trade with colonies, all you really need is to build a few hundred infrastructure and ship it to mars, then your civilians will build colony ships to move population from earth to mars automatically, also note every populated planet produces Infrastructure by itself, so even without any of your factories producing infrastructure you will have enough being made for significant long term growth of any colony anyway.
Regarding fuel, don't make your initial ship designs fuel hogs, larger engines with lower multiplier are more fuel efficient and for freighters the extra transit time with slower engines doesn't usually matter, but make a few high speed freighters just so you can move mass drivers and critically important installations fast as necessary. And don't forget to ensure the ships have enough range for whatever task you're giving them, a mining colony on nepture for example will need freighters with a range in excess of 10 billion kilometers. And finally when you do eventually have a ship run out of fuel somewhere deep in the kuiper belt, It doesn't take long to design and build one of these :
% Tyne class Tanker 500 tons 9 Crew 85. 4 BP TCS 10 TH 18 EM 0
1800 km/s Armour 1-5 Shields 0-0 Sensors 6/1/0/0 Damage Control Rating 1 PPV 0
Maint Life 57. 2 Years MSP 107 AFR 2% IFR 0% 1YR 0 5YR 1 Max Repair 6 MSP
Intended Deployment Time: 12 months Spare Berths 1
9 EP Ion Drive E. 386 (2) Power 9 Fuel Use 38. 58% Signature 9 Exp 7%
Fuel Capacity 230,000 Litres Range 214. 6 billion km (1380 days at full power)
Thermal Sensor TH1-6 (1) Sensitivity 6 Detect Sig Strength 1000: 6m km
This design is classed as a Fighter for production, combat and maintenance purposes
Small enough to be made in a fighter factory, which doesn't need retooling, the small engine takes 2 weeks for 5 20% bonus researchers to research, the ship only takes 6 weeks to make with the 60 fighter factorys you start with in a normal game. And greater fuel capacity can be had if you've researched small engineering spaces instead of the normal sized one this ship has on it.
Good luck.