Doel - Fin

[GJ]

I have a 16 foot Orkney fastliner with a 15hp outboard. Top speed was about 10 mph and no matter how I trimmed the outboard the boat would sit with its bow high in the water. I fitted a set of doel-fins to the outboard and it has made a great improvement.

The boat now run quite level (the bow is still pointing up a bit)
It is lighter to steer and holds its coarse better. But best of all now has a top speed of 13mph and 30% improvement for just 20 quid.

[mark]

you\'ll probably find fuel economy has gone up as well!

depending on hoe the motor is trimmed, you might get a bit more out of it by adjusting the motor trim a bit more, the nose will come up higher under power, but migh plane a lot beeter, and therfore be a bit faster

if there\'s anu rim adjustment available on the leg, move it so that the prop is closer to the transom, trial and error but can make a huge difference

my last boat had a 40hp johnson on it, adding doel fins ,and bringing the trim in, sent top speed from around 15knts to a scary 25!

that said thoug, 15hp might be a bit underpowered for a 16foot boat

[Charlton]

GJ surprised with a orkney that you could not trim it so bow even, how many do you take out with you and where do they sit, and where do you store all your gear sinkers, ropes, fuel tank etc. If you all the weight is near the back you will have problems with a small outboard. Try evening the weight out

[GJ]

There is normaly only 2 on the boat and I try to keep most of the gear toward the front of the boat so that there is more space at the back when you are fishing. The fuel tank sits right at the back but that will only weigh 4 stones when full. It might be like Mark says that the outboard doesn\'t have enough guts to push the back of the boat out of the water.

[Charlton]

try puttin the tank as far forward as you can, but tend to agree withhmarc altough longliners are pretty light, could also have something to do with the fact your hull is a displacement and not a planning hull, but should still ride on an even keel if everything trimmed and balanced properly. My first baot was a much heavier boat that yours and i only had a 10hp outboard on, and could still get it on an even keel. If nothing else works, chuch somebody overboard.

[mark]

fastliners are semi displacement, but do need a good shove from behind to get them on the plane, but the increase in power required, rises dramatically...

to get from 13 mph to 20 will need a leap to a 40 to 50hp motor

had a one years back, which managed about 18 flat out with a 40hp mercury on the back, but that was at a cost... keeping it just starting to plane at at about 10knots would give maybe 6 or 7 miles to the gallon, running it hard to get18 would drop that to about 2 miles to the gallon, makes it expensive to get to those off shore wrecks!

[GJ]

With things as they are now I can go out 6-8 miles fishing wrecks all day and get back in again on about 5 gallons. Although it would be nice to do 20mph the economics of getting the boat to do it, out weigh the benefits.

Next option ( in my dreams according to the wife ) would be a bigger boat.

[mark]

absolutely. thrashing the old boat last year in scotland, 32 miles done on the plotter....

18 gallons of petrol burnt! not a cheap day out!