When it comes to Boom Beach offensive unit you select the effective one that can help you to destroy the enemy village. The most important unit is the Gunboat; this gunboat is very useful to your attack and a unit that can help the assaulting unit.
Rocket launcher is one of the good unit and due to his heavy splash damage and also long range can able to destroy armies with low HP. When you upgrade this weapon the damage level will increase but the range is still the same.
Mortar is next to rocket launchers, this weapon should be put at the back of your base. Mortar is very useful and has a long range attack but the bad thing about mortar you have to wait 3 seconds per attack due to reloading processes.
Sniper Tower is very effective to human base unit, a long range tower that can kill a single troop in one hit. If you upgrade the sniper tower the damage and range will be boosted. Place the Sniper Tower close to your mortar they are good duo when it comes to long range.
Flame Thrower is short range but heavy in damage. This tower is every effective for troops and vehicle. The bad thing about flame thrower is he by having a short range; he is not good when the attacking unit is a long range type.
Shock launcher is good for matching up sniper tower; every attack of this tower is areal which mean once a group of unit is within the range splash radius will be affected in one attack. This tower must be place in front of your base.
Cannons are very common they may be simple from the start but when you upgrade this tower it is very effective from enemy troops to vehicle unit. Cannons are mid range but they are good in attack due to fast reload and fast cast rate.
Machine Guns the weapon that you should have in front of your base and also to your corner defense. This machine gun tower is very flexible they are effective in troops and vehicle units. They may not be good in damage but they are a good defensive tower because they can delay attacking unit.
Boom cannons are one great tower that is good to be place at the center of your base. A long range and heavy damage that can cripple attacking unit. The down side of this tower is very slow in reloading.