Let's talk speed

[stinkynathan]

I got the boat out on some big water on Lake Oahe tonight and borrowed my dad's GPS to check my speed. My loadout is as follows:

Starcraft 14' Seafarer
~1986 Mariner 15hp
6 gallons of fuel in rear
1 battery in bow
6 poles, tackle bag, bait
No decking
me (220)
Girlfriend (assuming ~135)

I was only able to hit about 13.4 with all of that in the boat no matter what I tried with placing her, adjusting trim, and moving the gas tank. Alone, I was able to hit 16.1.

Now, my prop has been dinged, but I did bend back the one little divot on one blade and filed off all of the rough edges. Maybe I don't remember how slow our old boat was, but 13.4 with 2 people seems pretty slow to me. I feel like it's _just_ barely getting up on plane. I was hoping for about 20 with just me and 17-18 with a passenger. Tomorrow morning I'm going out with my dad and he weighs about 225, too. Should be interesting.....

At the least I need to get a Tiny Tach and make sure this thing is adjusted and propped correctly. I'm thinking I'm going to have to chase down a 30-40 hp motor this summer since this thing is rated for a 40.

What speeds are other people getting with similar setups?

 

[grizzly]

i'm certainly no expert on what to expect with different setups for speed, but it seems a bit on the slow side to me.
my 12' vee, decked, one battery close to bow, 3 gal of gas in stern, 1980 7.5hp evinrude, usual tackle, TM on bow, and 25lb dog, goes -

15.7 mph on my gps when alone. (i'm 155lbs)
add my girlfriend (120lbs) we slow to 14.2 mph.
add our 9 yr old daughter (80ish lbs) and we slow to 12 mph.

these numbers were on a fairly calm day with slight chop, if the lake was smooth as glass i feel i'd add atleast one mph or slightly better. i don't know for sure cause i've only had my gps turned on a couple times in the boat.

 

[Loggerhead Mike]

with me and my a co angler im running about a mean 5mph's with my 3hp johnson :mrgreen:

 

[crazymanme2]

Is your cavitation plate even with the bottom of your boat? What pitch prop you running?
My boat is a 12 footer with a 15hp with a 10 pitch prop & I run a solid 25 mph.
When I put my 20hp on it it'll run a little over 30mph with the same pitch prop.Horse power does make a difference.

 

[Quackrstackr]

I don't know what your takle bag weighs but you are pushing around 450 lbs of listed gear not even counting it. I would say that you probably are not too far off of your top speed, depending on hull design.

 

[stinkynathan]

Is your cavitation plate even with the bottom of your boat? What pitch prop you running?
My boat is a 12 footer with a 15hp with a 10 pitch prop & I run a solid 25 mph.
When I put my 20hp on it it'll run a little over 30mph with the same pitch prop.Horse power does make a difference.

The prop is a 9.25x10P aluminum.

The cavitation plate was an inch low. I shimmed it up with a piece of 1x2 steel. Probably won't be on a lake big enough to open it up tonight, but I will be able to do that tomorrow.

Will report in on speed once I get it out on the water.

 

[cjldad]

You don't sound too far off.. I have a 14' Starcraft Super Star and I can only obtain a max of 22mph with my 15hp Yamaha.. Total weight in the boat is probably 400lbs including myself.. If I remember correctly, the Seafarer is wider, or atleast wider than my 48" boat.. All of that added up, plus a prop that has been bent/fixed and maybe a weaker 15hp motor will slow you to that speed.. For the record, I have everything in the bow of my boat.. (Battery, fuel tank, anchor, misc. other items) And my motor sits probably 2 inches lower than I would like, but doesn't bother me that much.. Wish I would have changed that when I swapped out the transom, but too late..

What's the max motor for that hull??

Also, I think I'm running a 9.25 x 10.5 prop....

 

[stinkynathan]

I adjust the motor up an inch and was able to get it up to 17.2 on the GPS on a tiny lake. I think I could have gotten a couple more points out of it if I had more space. It got us up to 12.x on big water with a 15 mph wind. I still didn't really feel like it was fully planed out at that speed.

At this point, I'm thinking replacing the prop and checking the RPMs at WOT are the next step. I now remember a change that I made to the throttle that may affect power. ...but I'll take that up in the motor forum.

You don't sound too far off.. I have a 14' Starcraft Super Star and I can only obtain a max of 22mph with my 15hp Yamaha.. Total weight in the boat is probably 400lbs including myself.. If I remember correctly, the Seafarer is wider, or atleast wider than my 48" boat.. All of that added up, plus a prop that has been bent/fixed and maybe a weaker 15hp motor will slow you to that speed.. What's the max motor for that hull??

Also, I think I'm running a 9.25 x 10.5 prop....

The boat is a 1448 and is actually rated for a 40hp motor. It's a hull from the 60s though, so I assume that would mean a 35 hp in today's motors.

Hopefully with some motor work and a new prop I can get into the 20s. I still see a 25-35 hp motor in my future, though, and hopefully this winter.