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Rip it up
08-01-2013, 06:54 AM
Hello members.

Chasing some help to increase bow lift on my little forward steer fibreglass runabout. Cruise craft rogue 14ft. Current setup Yamaha 60hp 4st. 13 1/8 x 13" prop.

It has recently built a lightweight transom and floor in the boat. This has changed the boat balance. With two people in the boat the nose will not lift when I trim the outboard.

What would be the best solution to help encourage bow lift.
Motor bolt heights
Prop replacement. ( it's chewed up pretty bad) aluminium yammy.
Fast tail foil. http://www.fastcompanymarine.com/fast_company_technical.php

Cheers guys help fix my crabbing weapon.

Chimo
08-01-2013, 07:04 AM
R I U

1 Check motor height, lift if neeeded, (cav plate to be at or above water surface when boat on plane)
2 replace prop to achieve motor specified revs at WOT
3 Foil will aid lift to allow slower plane speed. At med high speed the motor should be trimmed out so foil is more or less clear of the water surface to avoid drag

Are you having fun yet?

Cheers
Chimo

Dan5
08-01-2013, 07:41 AM
I'd be looking at Engine height and then if your still not happy i'd look into a permatrim.......

Dan

Fed
08-01-2013, 07:46 AM
Too much weight up the front or the hull is hooked.

Horse
08-01-2013, 07:59 AM
I don't think wedges are going to give any more bow lift. They are used to correct transom angle to keep the bow down. I would be looking at a couple of options. Firstly see if you can move weight aft. If you have changed the centre of mass then the hull may not perform as designed. Weight foreward brings broaching to mind.
Secondly, look at a stainless prop which is raked. This is the cupping at the end of the blade. This will give you significantly more bow lift

Dan5
08-01-2013, 08:06 AM
I don't think wedges are going to give any more bow lift. They are used to correct transom angle to keep the bow down. I would be looking at a couple of options. Firstly see if you can move weight aft. If you have changed the centre of mass then the hull may not perform as designed. Weight foreward brings broaching to mind.
Secondly, look at a stainless prop which is raked. This is the cupping at the end of the blade. This will give you significantly more bow lift


Yes you are correct.......i have misread/understood the post........wedges will keep the bow down not up....my mistake.

Dan

Gon Fishun
08-01-2013, 10:05 AM
Have you checked for weight distrubution. I noticed in an earlier post you would have the battery up front. Might be to much weight up front with people, anchor etc etc.

ericcs
08-01-2013, 11:28 AM
would have thought the extra weight of a 60 4st would make it more nose high than nose down, especialy on a little rogue. won't fitting a foil on the engine just help keep the nose down?

cormorant
08-01-2013, 11:59 AM
throw 2-4 jerrycans full of water down the back and see what happen. will determin if you have a hook pot or belly on teh planing suface.
Put a normal ally good condition prop on it to test. Crap prps can cause all sorts of stern lift issues and so can 4 bladers . It is not the size but teh shape and design that matters in regards to lift
Leave fat mates on land - get light mates and still get you crabs. Crabbingis a cut throat business.!!!

Rip it up
08-01-2013, 01:47 PM
Just noticed that my iPhone changed the forum name. Sorry about that.

First of all a little background for those who missed the rebuild thread.

The boat originally had a 1976 Johnson seahorse 2st on the back. Changed to 4st 60hp in June. Put 40hrs on the motor with original floor that was damaged and wet.
Twin battery in stbd aft corner. 25L fuel in port.

Always been a forward steer.

Rebuild took 150kg of wet timber out. And put 60kg back in. Moved to a single gel battery under passenger seat.
Chasing a second fuel tank now. To put in each corner.

So now the weight distribution has changed.

I will call Solas to discuss a SS prop. Fresh blades should help.

The motor was bolted back into the same holes.

So in theory the cav plate should be closer to the surface if the bow sits lower.

Revs has not changed. Before and after still 5400-5500 WOT depending on load.

Yes I am very happy with the boat.

Rip it up
08-01-2013, 01:49 PM
I am confident the hull is not hooked. As the hull was rebuilt in a cradle. The deck lid came off once in the cradle. Then replaced with ease into exactly the same position. No tweaking needed to install.

Fed
08-01-2013, 05:11 PM
I hope it's not hooked RiU but I'd check it anyway before spending money on other things trying to fix it.
I just read your other thread, great job you don't muck around, I've seen builds take years to do what you have done in weeks.
After seeing your other thread you could probably unhook the hull in half a day.

Rip it up
09-01-2013, 05:37 AM
Cheers fed.

I will setup some string lines and straight edges to check the HOOK.
It still needs a cosmetic touch up. .
So I will be taking motor off shortly and flipping the hull for a polish and clean up of some nicks.
I will be respraying the lid and transom when the bottom is sorted out.

tunaticer
09-01-2013, 05:49 AM
The lighter transom will not be giving you grief I think. Weight placements in the fore end will give you the problems you are experiencing. Move the battery back aft and whack an esky with the same quantity of water in it as what you want to increase the fuel and go for a run. Move that esky about to work out the best location for that weight. Be sure you have your usual deckie on board for this as his weight will change the atitiude of the bow too.
Check a dimension from each chine at the transom to the skeg of the motor when fully lowered, it could be half an inch to one side which dramatically changes the boats attitude.

Rip it up
09-01-2013, 05:58 AM
Tunaticer thanks for the ideas.
I have a 70L long esky which sits against the motor well in its normal position. I will load this up fully and check the trim.
And I will throw a tape over the motor fully down.

I originally had a safety gear shelf up under the bow. Which stored my flares, life jackets. Not a lot of weight 5kg tops. But it was under the bow.

Before the rebuild the wet timber from the floor had settled into the last 2ft of the hull. This is the major contributing factor for the old bow lift I was getting. I'm talking 100kg of wet mulch type timber.

Time on the water moving weights around should help.

I got a response from solas last night. They suggested I move the motor up a hole. And throw on a new 13" pitch prop.