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Author Topic:   Hull with Hook In Bottom

bullet posted 06-18-2010 02:33 PM ET (US)
On my 14-foot tri-hull skiff I recently replaced my old Mecury 35-HP twp-cycle outboard with a 2005 Mercury 50-HP two-cycle outboard. The boat runs great at half to three-quarter throttle, but the bow starts to dig in at any higher speeds. Trimming the motor does not help the bow lift any. When I look down the bottom of the boat hull I see a hook in the last foot of hull. Will raising or lowering the engine help the boat perform better? Or, will I have to fix the hook in hull to ever get it to run correctly? Any ideas would be appreciated. Thanks
Buckda posted 06-18-2010 02:47 PM ET (US)
Bullet -
What is the max HP rated for this hull. It seems that the designers didn't want it to be a high-speed vessel, and the hook was DESIGNED into the boat to make it run relatively flat at slower speeds.
I don't think you can change that characteristic with more HP unless you change the design of the boat.
contender posted 06-18-2010 04:24 PM ET (US)
Buckda is correct: you need to take the hook out of the hull.
bullet posted 06-18-2010 05:47 PM ET (US)
Thanks guys, I do not know what max hp was on boat. When I found boat twenty years ago it was leaning up against a tree with small trees growing through the deck. I totally rebuilt boat and made it a center console.I'm guessing it was not rated for alot of hp. With the 35 hp it performed well, but it even road nose down at wide open with it.The 50 hp magnified the problem. Guess I will be happy with half throttle, it is still plenty fast. I use it for running the marshes and fishing. Guess next spring I might try and glass the hook out. Thanks again, Dave
jimh posted 06-19-2010 10:25 AM ET (US)
I think Boston Whaler incorporated a bit of hook in the hull bottom of the original 13-footer, probably to keep the bow down at higher speeds. Is my recall correct?
Tom W Clark posted 06-19-2010 12:08 PM ET (US)
Jim -- No, not quite. The hook in the 13 foot Whaler was there to help make it easier for small outboard motors to get the boat on plane and keep it there, something a "hook" will do.
The classic 13 foot Whaler was never designed to go 40 MPH but it was designed to plane with as little as 10 HP.
It is sometimes hard to imagine the need for a hook in this age of power trim and tilt, trim tabs and large outboard motors up to 300 HP or more; back in 1958, a 40 HP outboard WAS a big outboard.
number9 posted 06-19-2010 02:52 PM ET (US)

quote:
Will raising or lowering the engine help the boat perform better?

Didn't see this question addressed in the previous replies. Since I have no known experience with a hooked hull it would be good to know for future reference.
Bill
Ric232 posted 06-19-2010 05:18 PM ET (US)
If you remove the hook, the boat will probably porpoise quite a bit with any trim. Just something to consider.
Russ 13 posted 06-22-2010 02:39 PM ET (US)
Having a 86 13' with a 40 @ stroke Yamaha.
Raising the engine mounting height will not reduce the
hook's affect on the hull.
If mounted too high, it will just ventilate the prop, increasing it's slip.
This design was not designed to run fast, as there are no lifting strakes on the hull.
The 13' is VERY weight sensitive, moveing weight along the centerline, helps it's water manners.
I would suggest moveing the battery or fuel forward, try different positions, to find what works best for you.
pcrussell50 posted 06-24-2010 06:21 PM ET (US)
My take on all this:
If you use a SPORT 13, which has a hooked hull, in the ocean, MOST days will be to rough to go 40mph, even if there was no hook and you had plenty of power to do it. If you use your boat in water that is smooth enough to go fast most of the time, AND speed is important to you, you should probably not have a Whaler.
-Peter
Seminole Jack posted 06-25-2010 11:11 PM ET (US)
Why do some folks think a 13 ft. Whaler is a performance boat and try to make one out of it?
thegage posted 06-26-2010 12:50 AM ET (US)
For the same reason they put a big engine in the mid-size Pontiac Tempest and created the GTO: because it's there!
John K.
bullet posted 06-26-2010 01:23 PM ET (US)
Some of you guys need to start at the beginning of the thread. I am not talking about changing a 13 Whaler, my 13 runs fine with a 50 hp Mercury. I have an older tri hull that I just repowered and it runs bow down, (digs) at higher speeds. There is a hook in the last foot of the hull. I know this is hurting the performance of the boat. I have glass and matt on the way to remedy this situation. Thanks Buckda and Contender for your input.
David Pendleton posted 06-26-2010 05:27 PM ET (US)
Can someone explain to me what this "hook" is?
Whalerdog posted 06-26-2010 07:26 PM ET (US)
hook is a concave surface on the hull bottom in instead of straight.
How big is the hook on the boat?
bullet posted 06-28-2010 10:32 AM ET (US)
About the last 18" of the bottom of hull.

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Author	Topic: Hull with Hook In Bottom
bullet	posted 06-18-2010 02:33 PM ET (US) On my 14-foot tri-hull skiff I recently replaced my old Mecury 35-HP twp-cycle outboard with a 2005 Mercury 50-HP two-cycle outboard. The boat runs great at half to three-quarter throttle, but the bow starts to dig in at any higher speeds. Trimming the motor does not help the bow lift any. When I look down the bottom of the boat hull I see a hook in the last foot of hull. Will raising or lowering the engine help the boat perform better? Or, will I have to fix the hook in hull to ever get it to run correctly? Any ideas would be appreciated. Thanks
Buckda	posted 06-18-2010 02:47 PM ET (US) Bullet - What is the max HP rated for this hull. It seems that the designers didn't want it to be a high-speed vessel, and the hook was DESIGNED into the boat to make it run relatively flat at slower speeds. I don't think you can change that characteristic with more HP unless you change the design of the boat.
contender	posted 06-18-2010 04:24 PM ET (US) Buckda is correct: you need to take the hook out of the hull.
bullet	posted 06-18-2010 05:47 PM ET (US) Thanks guys, I do not know what max hp was on boat. When I found boat twenty years ago it was leaning up against a tree with small trees growing through the deck. I totally rebuilt boat and made it a center console.I'm guessing it was not rated for alot of hp. With the 35 hp it performed well, but it even road nose down at wide open with it.The 50 hp magnified the problem. Guess I will be happy with half throttle, it is still plenty fast. I use it for running the marshes and fishing. Guess next spring I might try and glass the hook out. Thanks again, Dave
jimh	posted 06-19-2010 10:25 AM ET (US) I think Boston Whaler incorporated a bit of hook in the hull bottom of the original 13-footer, probably to keep the bow down at higher speeds. Is my recall correct?
Tom W Clark	posted 06-19-2010 12:08 PM ET (US) Jim -- No, not quite. The hook in the 13 foot Whaler was there to help make it easier for small outboard motors to get the boat on plane and keep it there, something a "hook" will do. The classic 13 foot Whaler was never designed to go 40 MPH but it was designed to plane with as little as 10 HP. It is sometimes hard to imagine the need for a hook in this age of power trim and tilt, trim tabs and large outboard motors up to 300 HP or more; back in 1958, a 40 HP outboard WAS a big outboard.
number9	posted 06-19-2010 02:52 PM ET (US) quote: Will raising or lowering the engine help the boat perform better? Didn't see this question addressed in the previous replies. Since I have no known experience with a hooked hull it would be good to know for future reference. Bill
Ric232	posted 06-19-2010 05:18 PM ET (US) If you remove the hook, the boat will probably porpoise quite a bit with any trim. Just something to consider.
Russ 13	posted 06-22-2010 02:39 PM ET (US) Having a 86 13' with a 40 @ stroke Yamaha. Raising the engine mounting height will not reduce the hook's affect on the hull. If mounted too high, it will just ventilate the prop, increasing it's slip. This design was not designed to run fast, as there are no lifting strakes on the hull. The 13' is VERY weight sensitive, moveing weight along the centerline, helps it's water manners. I would suggest moveing the battery or fuel forward, try different positions, to find what works best for you.
pcrussell50	posted 06-24-2010 06:21 PM ET (US) My take on all this: If you use a SPORT 13, which has a hooked hull, in the ocean, MOST days will be to rough to go 40mph, even if there was no hook and you had plenty of power to do it. If you use your boat in water that is smooth enough to go fast most of the time, AND speed is important to you, you should probably not have a Whaler. -Peter
Seminole Jack	posted 06-25-2010 11:11 PM ET (US) Why do some folks think a 13 ft. Whaler is a performance boat and try to make one out of it?
thegage	posted 06-26-2010 12:50 AM ET (US) For the same reason they put a big engine in the mid-size Pontiac Tempest and created the GTO: because it's there! John K.
bullet	posted 06-26-2010 01:23 PM ET (US) Some of you guys need to start at the beginning of the thread. I am not talking about changing a 13 Whaler, my 13 runs fine with a 50 hp Mercury. I have an older tri hull that I just repowered and it runs bow down, (digs) at higher speeds. There is a hook in the last foot of the hull. I know this is hurting the performance of the boat. I have glass and matt on the way to remedy this situation. Thanks Buckda and Contender for your input.
David Pendleton	posted 06-26-2010 05:27 PM ET (US) Can someone explain to me what this "hook" is?
Whalerdog	posted 06-26-2010 07:26 PM ET (US) hook is a concave surface on the hull bottom in instead of straight. How big is the hook on the boat?
bullet	posted 06-28-2010 10:32 AM ET (US) About the last 18" of the bottom of hull.