Boatmad.com


Reply
 
Thread Tools Display Modes
 
Old 01-09-2016, 01:52 PM   #1
Registered User
 
willwood6's Avatar
 
Country: England
Location: Manchester
Occupation: PM
Boat make: Phantom 18
Engines: Rude 150HO
Cruising area: Windermere/ Barrow

Join Date: Jan 2008
Location: Manchester
Posts: 226
Evinrude 250HO on Phantom 18

Hi guys,

Given this set up a real good go over the last 2 seasons and I have it somewhere near drivable.
Unfortunately I am conceding defeat with the huge torque and extra weight of the HO over my old merc. I just cant get the boat to settle. More so now with the magnum gearbox over my broken lightning box.

Thinking of either dropping the rude down to a 175 or 150HO or possible going to a P20/21 or maybe something else, Bernico maybe.

Anyone got any thoughts? Open to ideas at the moment. Season ends in a month and need to be sure of what I want to do by then.

Thanks in advance
Will
__________________

willwood6 is offline   Reply With Quote
Old 03-09-2016, 10:41 AM   #2
Registered User
 
glen76's Avatar
 
Country: england
Location: southampton
Occupation: engineer
Interests: lots
Boat make: scorpion 8.1
Engines: 250HO
Cruising area: solent

Join Date: Mar 2004
Location: southampton
Posts: 1,338
Why did you switch to m2 gear case? How much did it change it?

What's height of engine and position on transom? Any pictures?
__________________

glen76 is offline   Reply With Quote
Old 05-09-2016, 09:14 AM   #3
Registered User
 
Burty's Avatar
 
Country: UK
Location: Weston Super Mare
Occupation: Electrical Engineer

Join Date: Mar 2004
Location: Weston Super Mare
Posts: 6,351
Send a message via AIM to Burty
Phantoms are just too narrow to cope with the torque of the new style motors, even P21's dont like the 300xs
Burty is offline   Reply With Quote
Old 06-09-2016, 04:38 PM   #4
Registered User
 
willwood6's Avatar
 
Country: England
Location: Manchester
Occupation: PM
Boat make: Phantom 18
Engines: Rude 150HO
Cruising area: Windermere/ Barrow

Join Date: Jan 2008
Location: Manchester
Posts: 226
Lightning gearbox snapped the prop shaft clean in half at the gear selector end.
Magnum is 2:1 ratio so revs its nuts off with the 24 I was running but anything bigger is almost impossible to drive with the torque.
All set up on a full transom so inch or so below the hull line.
The boat is fine for regular use with the smaller prop but the gearbox ratio kills it.
Top heavy nature of the engine doesn't help the racing and I'm a bit worried it'll rip the back out of my 26 year old transom!

Decision is now made to re-power over the off season. Will be looking for 150HO or 175 ETEC or maybe go back to a racing merc. Maybe a good 280 ROS or something of the like.
willwood6 is offline   Reply With Quote
Old 06-09-2016, 05:28 PM   #5
Registered User
 
Country: UK
Location: Bromley
Occupation: shopfitter
Interests: Boating jet ski and Scuba diving
Boat name: Insane
Boat make: Phantom 21 1990
Engines: Evinrude 250 HO
Cruising area: Isle of Sheppey

Join Date: Feb 2013
Location: Bromley
Posts: 67
I have 250HO on my P21. It is running a 24" five bladed Trophy Plus prop. The engine is bolted direct to the transom with the pointy part of the gear box running about 5-6" below the boat pad. This is not ideal and i will be fitting a lifter to get to run level/1" below depending on the water pickup. At present the engine will torque lean the boat at about 3000 revs, which is easily solved by trimming the engine as soon as you accelerate. The boat hits 76 on the i-commard GPS before it starts chinning. Needs a little playing with set up wise, maybe i will also fit some trim tabs.
May be its a little large for a 18 but i would get some to video you and see how it sits in the water.
Purple 21 is offline   Reply With Quote
Old 06-09-2016, 09:34 PM   #6
Registered User
 
willwood6's Avatar
 
Country: England
Location: Manchester
Occupation: PM
Boat make: Phantom 18
Engines: Rude 150HO
Cruising area: Windermere/ Barrow

Join Date: Jan 2008
Location: Manchester
Posts: 226
Hope the file uploads. Sits pretty well on the water i think you will agree. Be good for a record run!
Attached Thumbnails
Click image for larger version

Name:	12961527_10209645715120243_4450901579697206812_n.jpg
Views:	320
Size:	33.5 KB
ID:	46551  
willwood6 is offline   Reply With Quote
Old 16-12-2016, 06:03 PM   #7
Registered User
 
Boat name: P21
Boat make: P21
Engines: Evinrude 250 HO
Cruising area: Solent

Join Date: Jul 2015
Posts: 92
I have a Mark 2 P21 with a 250 HO etec as well. I cannot run four blade props, simply twists the boat like a corkscrew. I'm running the Lightning gearbox so don't have to look for high numbered pitches. I have loads of props but managed to find A Raker 24 that seems perfect . I've had 73 mph on GPS with a four blade Bravo 25. I think this Raker will add a bit more to it, haven't managed to speed run it yet. Is yours a mark 2? Regards Dom.
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	275
Size:	110.4 KB
ID:	46875  
Fantom2 is offline   Reply With Quote
Old 20-12-2016, 08:11 PM   #8
Registered User
 
Country: Finland
Location: Helsinki
Interests: Everything fast
Boat make: Hydrostep 650, TG 5000XR, Kimach 450 Speed, Stopper
Engines: Merc 115 ProXS 4S, Merc 60 Formula Race, Yamaha 20
Cruising area: Helsinki

Join Date: Apr 2014
Location: Helsinki
Posts: 67
I know water conditions are quite different here up north, but the fact is that with pretty much any 250+ hp engine the prop torque is just too much to handle on a light weight boat if you bury the prop below surface. The only way to ease prop torque is to raise the engine on the transom. Don’t really know the dynamics of a Rude and its gearbox but would assume prop axle at pad is a good starting point. Merc suggests engine height on their sporty “racing” engines like 250XS and 300XS with a Sportmaster gearbox that the prop axle should be anywhere from even to 1½” above pad.

Personally I’ve had a lightweight P21 with a 250XS and now a heavier P21 with a 300XS. I’ve run both normally with prop axle around 1” above pad. Need to note that with the 250XS I used a 6" set back lift and with the 300XS a 4" set back lift. The P21 goes steady as a train, no chine walk and no excessive steering torque. You also gain quite a bit of speed. I’ve done 85mph with both and next summer the current one will be set up for 90mph.
Carrera is offline   Reply With Quote
Old 20-12-2016, 08:28 PM   #9
Registered User
 
Boat name: P21
Boat make: P21
Engines: Evinrude 250 HO
Cruising area: Solent

Join Date: Jul 2015
Posts: 92
That is very interesting and much appreciated. I will check and measure dimensions when I get chance. The etec 250 Ho is apparently about 283 hp at the prop and massive torque. I do use it as a general boat, ie A to B, skiing etc so a compromised boat for speed is probably not going to work for me, although never say never. I reckon im an inch or so below, a good source said don't go higher than 26 inches on the transom, but I'm very close to that. I will need a bobs nose if I go higher. Also won't the taller weight cause handling problems? I've also heard P 21 s don't go well with 15 inch legs so presumed your on 20 inch legs? Don't shoot be down if I'm talking rubbish , I accept it lol!
Fantom2 is offline   Reply With Quote
Old 20-12-2016, 08:29 PM   #10
Registered User
 
Country: uk
Location: salcombe
Occupation: semi retired
Interests: racing(middle east class 3 6l)
Boat name: still no worries
Boat make: phantom18
Engines: 2.5 efi
Cruising area: salcombe

Join Date: Dec 2007
Location: salcombe
Posts: 499
Hi
Try using a small hub big pitch prop ! (Small hub 26 laser) just to see what it's like., it will slip a lot getting on the plane if the nose cone is level with the bottom of the boat.
still no worries is offline   Reply With Quote
Old 20-12-2016, 08:47 PM   #11
Registered User
 
Boat name: P21
Boat make: P21
Engines: Evinrude 250 HO
Cruising area: Solent

Join Date: Jul 2015
Posts: 92
Thanks I will try that. I'm running a 24 pitch Mark 1 Raker, that feels great , not too much boat twist, I haven't had a chance to nail it but guessing 73 plus mph when I get the chance. I have raker 26 that pulls 5200 RPM AND 72 mph ( bear in mind I have a lightning 2 gearbox so spinning faster than most hence lower pitches. ( ps I have a vgc lightning gearbox1 shell if anyone needs) . Think I got a small hub Raker I can try. Too cold at mo tho. Really appreciating the info guys thanks.
Fantom2 is offline   Reply With Quote
Old 20-12-2016, 09:19 PM   #12
Registered User
 
Country: Finland
Location: Helsinki
Interests: Everything fast
Boat make: Hydrostep 650, TG 5000XR, Kimach 450 Speed, Stopper
Engines: Merc 115 ProXS 4S, Merc 60 Formula Race, Yamaha 20
Cruising area: Helsinki

Join Date: Apr 2014
Location: Helsinki
Posts: 67
It will add a bit to your overall cost but I would strongly suggest considering either a manual or hydraulic lift. It makes it so much easier to adjust the engine height depending on whether you want to cruise with friends, ski or go all out. That’s the way I do it

A Bob’s nose cone is a good choise. It will handle low water pick up quite high up and will provide an additional “ski pad” as well balancing the boat.
Then there is of course the eternal prop question. In order to got for top speed on a P21 you need a bow lifting prop. Hydromotive 4-blade and Turbo TXP OT4 have worked well for me. For cruising and water skiing you need a more neutral prop that lets the boat run on a longer water line. Can’t help you on those

You are correct in that the lower you can keep your weight the better. A higher point of gravity will eventually cause handling to be more difficult but nowhere close to the handling characteristics caused by an underwater 4-blade prop. I’ve always used standard 20” legs. I’ve never tried a 15” leg on a P21 but I wouldn’t hesitate to try one if I had a chance.

Don’t worry, won’t shoot you down. You will see, there are far more truths out there than you could imagine. There are the old school 80’s Steve Baker “true believers” who will tell you the P21 runs best with the engine straight on the transom, submerged and the most puritan belief is that a Laser2 is the best prop on earth At the other extreme we have the Nordic guys who are more accustomed to calmer conditions who will tell you get a hydraulic lift, jack up your engine and get a huge bow lifting prop. Guess which “religion” I believe in You’ll find the truth somewhere in between.

All in all, the P21 is about the best possible speed boat. You can make it very fast and still drive safely and you can also drive it more leisurely if you wish.
Carrera is offline   Reply With Quote
Old 20-12-2016, 10:05 PM   #13
Registered User
 
Boat name: P21
Boat make: P21
Engines: Evinrude 250 HO
Cruising area: Solent

Join Date: Jul 2015
Posts: 92
Great advice again, putting in the two arguments is good to hear because I've not only heard don't run 15 inch on the p21, I have also heard don't run an offset ( IE a lifter even with a small offset.) I assumed because it would mean deeper water away from the stern, remember I'm not in the know so assumption is silly on my part! Ps I had a four inch offset lifter, and thought even if I fit it ,will hit the sea star steering?
I think for now, because I'm skint and it's winter, my aim will be to optimise what I have. Come summer I may be a little more inclined to try a lifter and experiment. Someone told me over hub cleaver fir outright performance on calm ish water? Must admit all the phantoms 20 years ago on Hayling used to run hem from what remember. I only had laser 2 s tho.
Fantom2 is offline   Reply With Quote
Old 20-12-2016, 11:25 PM   #14
Registered User
 
Country: Finland
Location: Helsinki
Interests: Everything fast
Boat make: Hydrostep 650, TG 5000XR, Kimach 450 Speed, Stopper
Engines: Merc 115 ProXS 4S, Merc 60 Formula Race, Yamaha 20
Cruising area: Helsinki

Join Date: Apr 2014
Location: Helsinki
Posts: 67
There are a lot of differing opinions. I know it’s difficult to know who to believe. I’ve always run lifters on my Phantoms, had 6 Phantoms so far. I got one P21 from the UK without a lifter and it was a disaster. Drove it a couple of times and immediately put in an order for a lift. With the lift, or actually by lifting the engine 4”, I gained 5mph on that boat with the same crappy prop. With a better prop I added another 3-4mph. I have had SeaStar or Seastar Pro steering on all my Phantoms and never had any problems with the lifts.

You are right that you need to think things over and make changes, if any, gradually. That way you will gain knowledge on what works and what doesn’t.

In my opinion cleavers are not the optimum choice for a P21. Admitting though that I've only tried one on a P21. It was quite OK, but as a cleaver is very neutral the boat ran on a very long water line and was not particularly fast. You are right that 20 years ago it was the (only) way to go in racing. Nowadays cleavers are used more on very light small boats and cats. Most of the bigger monohulls and even cats use round blade props instead of cleavers. A cleaver can be fast, especially in the rough, but in calm conditions I opt for a normal prop. Also, especially an over the hub cleaver can be quite problematic in everyday use as it is so hard to get on plane. I must admit I used a 3-blade cleaver on my 3A boat last summer but it was really tricky to drive and nearly impossible to get on plane despite a hydraulic lift. If I will run the same setup next summer I already have a couple of more appropriate props for it on the shelve.

And don’t take me too seriously. The Laser and Laser2 are OK and can be even good props. Just note that they are proper props for a submerged setup and can be very dangerous if you lift your engine. They are very bad surface piercing props.
Carrera is offline   Reply With Quote
Old 21-12-2016, 08:07 AM   #15
Registered User
 
Boat name: P21
Boat make: P21
Engines: Evinrude 250 HO
Cruising area: Solent

Join Date: Jul 2015
Posts: 92
Great info again. I will be looking into all those options, I kick myself for selling my lifters now! Keep us informed with your progress, I'll do the same although it will be slow going for a while!
Fantom2 is offline   Reply With Quote
Old 23-12-2016, 05:53 PM   #16
Registered User
 
Boat name: P21
Boat make: P21
Engines: Evinrude 250 HO
Cruising area: Solent

Join Date: Jul 2015
Posts: 92
I've just measured my engine height. Its about 2.5 inches below the V. I may have the option on a lifter. It is quite a big offset 10 inch I think can you tell me what you think the optimum offset for the lifter is? As I will get it cut and welded exactly where I want it, if I buy it. I'll be in the market for one of those props as well lol. One step at a time though.
__________________

Fantom2 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Powered by vBadvanced CMPS v3.2.3

All times are GMT +1. The time now is 06:13 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×