To Trim-Tab or not to trim-tab (and other little speed improvements)

[Ovidgsd]

Probably buying a new 14' Livingston Boat (www.livingstonboats.com). Lightweight Fiberglass Catamaran style hull. Hull wieghs only 250lb aprox without rigging. I'll be putting my 25hp Johnson Outboard on the back. With 2 people, 1 dog, center console, trolling motor and battery, 6 gallons gas, and some gear, I'm guessing that I will get 18-20 mph planning at full trottle in flat water. I haven't tested the boat yet, and will test with 2 people, unrigged, using tiller drive before buying.

At this max speed, I figure that 2-5 extra mph would be a nice extra. How to get this extra is the question. 1) I could get a 3-4 blade prop. instead of the mfg 2 blade I have; 2) I could add trim tabs right from the start?

Not minding the extra cost of the tabs ($200 including install I'm guessing). Will I possibly get 2mph extra from the Tabs? Will I possibly get an extra 1-2mph from the better prop?

Are there any other little "tweeks" that I might consider?

Thanks!

[A Few Dollars]

You may gain a little with a 3 blade prop, but you're looking for a 10% - 25% increase in speed. The boat is rated for 40 hp with remote steering. While 10% is possible, you will never see a 25% increase without major modifications. I would stick with the tiller and leave the dog home.

[Bullshipper]

I have fished in this model and it had an old 30 hp, which would do about 22 mph with 2 fat guys, 15 gallons of gas, 5 rods and a cooler.
Shifting your weight back will get her nose up and help her plane, and helps with speed. The trim tabs will help her already good ride, but sticking the nose down with the tabs will lose you speed, and is not really recommended with a small cat with a low bow, when the chop stars to pick up. Keeping the weight down will really help a lot in all phases of the ride.
This is a small boat that won't be going too far out, so a2 mph difference won't make much of a difference in time anyway. I would rather spend my dough on a fish finder and a little transom hung livewell

[Ovidgsd]

Thanks guys for the suggestions!