kevlacat 5.2 and f60 yammies where did i go wrong

[fromeo]

Finally got my new f60's on but I don't seem to be getting the figures I am looking for ...At WOT 5400rpm for 22knts on yami digital speedo with 14k props with 10 hours on the motors .The motors are fitted so the first mounting hole in the modified pod is 325mm from the very bottom of the POD to the center of the first mounting hole. I do have another hole up adjustment if required . trimed right in the motor cav plate leading edge bottom sits 2 3/4inches above the bottom of the hull . Trimed so the cav plate sits plum vertical to the hull it sits 3 3/4 inches above the bottom of the hull to the lower bottom of the Cav plate. I have attached a few pics
Heaps of spray around the motors ( may need splash plates to solve that problem I think) any suggestions or comments would be appreciated see attached pic.

[peterbo3]

The yam site gives a rev range of 5-6000 RPM. The motors need to be able to rev out to 6K. You could be overpropped or too low. Use search.......there have been a few recent threads dealing with this exact issue. What does the dealer think? Have you been on to KC?

[Brumby]

I'd hazard a guess that with the motors set well back from the hull transom you could afford to go up some more. As said before though the other guys with KC5.2's should be able to give you more definite info. Good luck, disappointing to spend all that money and not get the result you hoped for.

[fromeo]

Thanks for the reply peter been through a few of the threads the height of the motors seems to be ok , may be some the the KC boys can confirm that , And from what i have read so far there choice of prop is a 15k seems strange to say the least havn't been in touch with KC factory as yet the dealer seems to think its ok ?

[finding_time]

Ok Your wot should be 5800 and 28 to 30 knots ! this IS what i get! The best ive gotten speed wise was 32 knots and that was down wind ( quite strong) one day I used to only get 5600 rpm with my 15k props but i damaged both props one day and when i had them repaired i had the cups ajusted to give me about 250 more rpm and this really made a differance with hullshot but i dropped maybe 1.5 knots which is fine by me! I think maybe your still to low but as soon as i can fine my motor pics i'll post!

[Captain Seaweed]

I am only guessing could you be over proped with motors sitting too deep and possibly under powered? I am only guessing here. I changed from 20 pitch to 17 as I had the same problem with rev range. I am thinking under powered as your getting spray off the motors meaning they are sitting too deep and not giving the desired output. I am only having a guess here mate and hope you can sort your problem out. I had a mate with a tinnie that the leg was too long and it had same symptoms.
Like Peter said I would also call KC.
Good Luck
Marty

[finding_time]

Spray is not an issue as it's very easily fixed with some deflectors , mine are made from that white cutting board material but Kevla cat get them made in alloy!

[fromeo]

Hi finding time,

some measurement confirmation would be great , at least I have one more hole up that i can adjust hopefully that will be enough.

[Dean1]

I tried the 14K's and they are NOT the prop for the appliciation. Are they the high thrusts?? I got the same figures as yourself, 4800 pulled only 18kts. With the 15K's I now pull 23 kts at 4800rpm. I havent reached any higher than 28kts but ive just discovered that Ive had 250 ltrs of water in my hulls. Yes Ian ive found my problem ;D This has happened when the plastic spinouts in the rear bulkheads were shattered and water filled the rear bulkheads, obviosly filling the next bulkheads as well. They are not perfecly watertight ive found. 2 3/4 inches from bottom of hull to cav plate is the spot on height, DO NOT CHANGE IT! Go to 15K's and you will be much happier. And check your hulls for water, ive installed extra spinouts in my floor to reassure in the future, a bit of drilling etc. is required here and there tho but worth the excersize. 14's are only required if carrying ALOT of weight. Cheers.

[FNQCairns]

Are both engines singing the same? You can test this roughly by raising one engine, observing wot and rpm, then swapping to observe the other engines numbers, are they adjusted toe in or out correctly (I have no idea what it should be on your boat), is the height correct?, looks good in the pic though but higher never hurts as a test.

Is it deano here that gets really good figures out of his cat? I have said it before i do have trouble getting my brain around some of the numbers obtained here on the cats with the 50/60 yamaha's but at the same time I do not disbelieve either, just do not have the experience in cats to say for sure.

cheers fnq

PS You simply cannot go down to 13p it will be a dog, 14 or 15 is where it's at with correct WOT (your dealers comments shows him as inexperienced or lacking in character)

[fromeo]

Hi Dean,

How did water get from the rear chamber where the original spinouts are located to the next sealed chamber how do you check are sealed chamber without drilling holes ? My rear chambers always gets full of water especially now with the extra weight on the 4 st letting a heao more water through the scuppers I just cannot seam to find spin off that actually work and keep water out anyone got any sugestions

[Dean1]

Hi Dean,

How did water get from the rear chamber where the original spinouts are located to the next sealed chamber how do you check are sealed chamber without drilling holes ? My rear chambers always gets full of water especially now with the extra weight on the 4 st letting a heao more water through the scuppers I just cannot seam to find spin off that actually work and keep water out anyone got any sugestions Well ive been reassured that the bulkheads are not watertight. Well when full of water( the rear bulkheads that is) and whilst motoring, things twist and flex a bit, thats boats. I was out the banks on a glassed out day, 2 of my overweight mates ( no names been said ;D ) stood on the plastic pieces of rubbish spinouts and this broke them through, causing the whole bulkhead to fill. I kept the boat in the water for another 8 hours, it was sagging in the rear bigtime but it was glassed out so I hung around. Take out your rear spinouts, get a battery drill with a 1/8 bit in it and drill forward as low as you can to the bottom of the hull forward to the next bulkhead and see what comes out. I replaced mine with alluminium spinouts but bought stainless ones up the coast here for cheaper. Sikaflex them to the floor. I can talk over the phone probably easier coz theres a few other little tricks ill have to tell you.

[finding_time]

Yes Ian ive found my problem ;D This has happened when the plastic spinouts in the rear bulkheads were shattered and water filled the rear bulkheads, obviosly filling the next bulkheads as well. They are not perfecly watertight ive found. .


I knew something was wrong!!! You have got me thinking about that water i get in my front storage areas now!

How did you find the water and how did you get the water out?

[fromeo]

Hi FNQ ,

the engines seem to run perfectly the cat is very responsive to trim , If I trim out to far its like a blizard around the back the starbord engine tries to drown the Port motor and vice versa man got to get those spray plates made up quick

[Dean1]

Spray plates on my old 70's, they now live on my F 60's. They will fix all spray issues they are amazing!

[fly_1]

I have had no dramas with mine either. And Ian, I used to get a bit of water in the front as well, and we traced it to a leaky side window. Water coming in along the side and staight into my forward storage areas. I just sicca flexed them shut, and have had no dramas since. I thought something was wrong Deano !!!!
I was told very very early on that you should check the rear hatches and pods every few months, as plenty of moisture can be sucked in thru the seals on the cheap plastic spinouts.
As far as props go,I have the 15's on mine and after 400 hrs in the last 2 yrs, they have never missed a beat...

[Dean1]

Well well what a difference 250 litres of in your hull can make!! I took mine for a spin today and man what a difference.

I knew I was in for a nice suprise as soon as I launched it. It sat up so much higher in the rear. About 60-70mm.

Gets up straight up on plane now and I got 30kts WOT at 5700- 5800rpm. Cruises very easy 23kts 4800 1.5-1.6 klms/ 1 litre.

Its got that floating feeling back. I'll try to put up a few pics of her in the water.

Fromeo put on 15's 2 3/4 inches from bottom of hull to cav plate check for water in hull and youll get the same figures. Cheers.

[finding_time]

All i can say deano is , About friggin time mate!!!


Fromeo

Deans figures mirror mine and dare i say Trents ( fly1) get the 15k's get them the right height and you'll be very happy!

[Dean1]

Ian I have pics how it used to sit in the water and what a difference.

The pics are 8mp and they wont load. The motors sounded like they were doing it so much easier today, quieter and so much punchier.

I'll look into getting the props shaved a bit. Bring on the hards trips!!

[lippa]

fat mates aye deano?is it the same fat mate that told you ya had water in ya hulls 4 months ago?

good to see its goin well again

[Scaredy Cat]

Has anyone with the 5.2m tried 4 blades,
Thanks to Ian and a trip out through Round Hill Bar in atrocious conditions (only to dump the frames of his fishing expedition), I have parted with my money and am now in the elite K/cat Club,;D ;D I am running 60 bigfoot Mercs that appear to be over propped with Vengeance 16p, talked to Solas last week and Steve recommended 4 blade/15p.
Any thoughts would be highly regarded, as $1300.00 is a lot of money if little extra is achieved. On Fri in great conditions on Morton Bay, Wot was 50km at 5200rpm, average WOT offshore 38km/h at 5000RPM, seems to dig in excessively and bleed speed in following sea and sluggish response in bar and to plan,

[insideout]

Very interesting question.... for a kc 5.2 is a couple of yammy f60s better than yammy f60 high thrusts? what is the difference? Thanks.

[FNQCairns]

Has anyone with the 5.2m tried 4 blades,
Thanks to Ian and a trip out through Round Hill Bar in atrocious conditions (only to dump the frames of his fishing expedition), I have parted with my money and am now in the elite K/cat Club,;D ;D I am running 60 bigfoot Mercs that appear to be over propped with Vengeance 16p, talked to Solas last week and Steve recommended 4 blade/15p.
Any thoughts would be highly regarded, as $1300.00 is a lot of money if little extra is achieved. On Fri in great conditions on Morton Bay, Wot was 50km at 5200rpm, average WOT offshore 38km/h at 5000RPM, seems to dig in excessively and bleed speed in following sea and sluggish response in bar and to plan,

Don't do it's bad advice, with the exception of where you are coming from then anything will see you happy, your potential well propped cruse speed which is what the cats are famous for ie the ability to sit at good cruise speed and take on all water till destination) will suffer as will fuel. the extra surace area it will afford is always nice but it's not a fair trade.

With respect your boat is a total dog ATM try not to fall into the trap of anything is better because it probably will be, it's expensive too! save your money. 3 blade 15p with low cup to help get those revs up might be better. Also if the 4 blade props are no cup it might be worth a test but with an eye toward not falling into the anything is better/see you happy. Try not to compromise on reaching full RPM, if you can get there it will all come together.

cheers fnq

[finding_time]

Very interesting question.... for a kc 5.2 is a couple of yammy f60s better than yammy f60 high thrusts? what is the difference? Thanks.


Nup , you need the high thrusts for several reasons but the main one is leg lenght! It keeps the power head out of the water

[finding_time]

Has anyone with the 5.2m tried 4 blades,
Thanks to Ian and a trip out through Round Hill Bar in atrocious conditions (only to dump the frames of his fishing expedition), I have parted with my money and am now in the elite K/cat Club,;D ;D I am running 60 bigfoot Mercs that appear to be over propped with Vengeance 16p, talked to Solas last week and Steve recommended 4 blade/15p.
Any thoughts would be highly regarded, as $1300.00 is a lot of money if little extra is achieved. On Fri in great conditions on Morton Bay, Wot was 50km at 5200rpm, average WOT offshore 38km/h at 5000RPM, seems to dig in excessively and bleed speed in following sea and sluggish response in bar and to plan,

Scaredycat

Mate Fnq is spot on! As usual !;) But you have to do something as at the moment your trying to bite of more water than your engines can chew! Get you Revs at wot to 5800 and you'll get your speed! I haven't had much to do with the big foot mercs but there specs are very similar to the yami's so the performance should be similar! Trent ( Fly1) has tried many differant props from solas but settled on the standard Yami 15k alloy props as they offered the best all round performance! As fnq sais a 3 blade prop with lower pitch may well be the go as they work on the yami's.

Good to see there is another kc in the pba you can start giving that kittycat a run for his money!;D

ian

[Dean1]

fat mates aye deano?is it the same fat mate that told you ya had water in ya hulls 4 months ago?

good to see its goin well again Yes Bryan thats correct it was Santa Claus ;)

[Dean1]

Scaredycat

Mate Fnq is spot on! As usual !;) But you have to do something as at the moment your trying to bite of more water than your engines can chew! Get you Revs at wot to 5800 and you'll get your speed! I haven't had much to do with the big foot mercs but there specs are very similar to the yami's so the performance should be similar! Trent ( Fly1) has tried many differant props from solas but settled on the standard Yami 15k alloy props as they offered the best all round performance! As fnq sais a 3 blade prop with lower pitch may well be the go as they work on the yami's.

Good to see there is another kc in the pba you can start giving that kittycat a run for his money!;D

ian Ye I wouldnt be too keen on the 4 blade Solas Props myself.. I spoke to solas recently and they are doing a 13p 3 blade stainless job that they claim gives you the revs easily with the speed as well. They gaurantee them, if not happy you dont pay. Ive been thinking about giving them a run! Nothing to lose only performance to gain! Solas claim that yamaha "K" series props are a bad design altho im happy with mine now. $1100 for the pair.

[BM]

Scaredy Cat,

Mercury make the best props in the business, hands down. Stick with Merc to get the right props for your rig.

cheers

[Dean1]

Scaredy Cat,

Mercury make the best props in the business, hands down. Stick with Merc to get the right props for your rig.

cheers BM good call i know a guy with F 60's on a 5.2 kc that had Stainless Mercury Vengenance (whatever their called) props and raved about them. Merc props do fit yammies hey??

[BM]

Merc props fit everything mate! You buy the hub you need to suit your brand of outboard and pop it into the prop. Pretty logical really. Why just make props for your own engines when that same prop can be made to fit every engine.

Since the dawn of boating Merc have spent the most on prop R&D and as such they are the market leader.

Cheers

[Scaredy Cat]

Scaredy Cat,

Mercury make the best props in the business, hands down. Stick with Merc to get the right props for your rig.

cheers


Can you suggest the best people to talk to in Brisbane, as I’m a bit reluctant to go back to the dealer that put the existing set-up together.:P
Has anyone got the rest of the yammies prop details- size, part No, as it would be good to get the Merc equivalent ::)

[Mr__Bean]

Are you sure you need (2x) 4 blades for your 120 combined horsepower?

Sounds more like (2x) 3 blades would already give very good grip on the water.

Adding the extra drag would seem contradictory to what you guys are trying to achieve here.

- Darren

[Scaredy Cat]

Scaredycat


Good to see there is another kc in the pba you can start giving that kittycat a run for his money!;D

ian

With the threat of starting another debate, does that mean I can fish the PBA 1770 week and then get another bite of the cherry by backing up for the Ausfish week. :D :D
He will be harder to catch now he has the 90 Suz :-/ , we will both have to work together 8-)

David

[finding_time]

Can you suggest the best people to talk to in Brisbane, as I’m a bit reluctant to go back to the dealer that put the existing set-up together.:P
Has anyone got the rest of the yammies prop details- size, part No, as it would be good to get the Merc equivalent ::)

There just the standard Yami 15k alloy props!

[finding_time]

He will be harder to catch now he has the 90 Suz :-/ ,
David

Just means he's burning more fuel!;D ;D

[Dean1]

Just means he's burning more fuel!;D ;D With a bum heavy rear!! Sorry Wayne had to say it ;D

[FNQCairns]

Can you suggest the best people to talk to in Brisbane, as I’m a bit reluctant to go back to the dealer that put the existing set-up together.:P
Has anyone got the rest of the yammies prop details- size, part No, as it would be good to get the Merc equivalent ::)

The yam prop is 6E5-45947-00-EL (I think), 13.5 x 15, an option for you might be Michigan wheel equivalent # 101032, there is also Turning Point with the torq flow equivalent hub, I have no idea just how close the cross references actually are, Mercury do not make a good equivalent that I am aware of anyway.

BTW those 16p props you have are pretty rare and sought after second hand they pull good prices for a prop secondhand around $350 at times, sell like lollies at $250 on ebay.

cheers fnq

[kitty_cat]

deano you know jelousy is a curse ,

i will try a few diferent engine hights with scaredy cats 1900 new model
but will advise against 4 blades as i have triied them and they give too much stern lift (dangerous in a cat and will cause bow steer)


dont mind the banter and as for a little friendly rilvalry between the cat owners is fine by me bring it on because as we know we are in a league off our own.
but just so people know
fuel 0.8 - 0.9ltr per klm 200klms trip 170lts fuel not bad and i dont mind using all off the 180 hp and untill the box is full and 3 fat buggers in the back no wet deck bit different with the 3 guys down back and full esky (just some facts so potential 90hp suzuki buyers dont get put off )

wayne

[John_R]

Hey Scaredy Cat, I sent Ian a PM like you asked. Coorparoo Marine is a Mercury dealer - maybe try them.

Wayne - are you doing the Ausfish Trip in Sept or the PBA one in Oct? I suggested to PBA that Oct is no good due to school holidays and no houses available, but they have not responded yet.

I reckon PBA should go up in Sept with Ausfish.

[kitty_cat]

hey john
my responce is in m & g but yes ausfish week is better for me but will be there for both 4 days ausfish 1 weekend pba
still havnet got a bite on witch team iam on ,they are too busy fighting over shirt colors

wayne

[BM]

Scaredy Cat,

I don't have a

[BM]

Scaredy Cat,

I don't have a listing with me but try a respected Merc dealer in your area or try The Prop Shop here in Melbourne. They are very good and they are Merc prop dealers also. They will be able to help but they may also be able to steer you towards a similar outfit in Bris.

Cheers

[Dean1]

hey john
my responce is in m & g but yes ausfish week is better for me but will be there for both 4 days ausfish 1 weekend pba
still havnet got a bite on witch team iam on ,they are too busy fighting over shirt colors

wayne Hey Wayne good to see you didnt take it to heart ;D Another 60hp could be handy but im pretty content for now! You should check your hull for water, you never know. When is Ausfish week???

[Scaredy Cat]

Thanks to all, and let the games begin,
I will get a set before going to Rainbow Beach next weekend and look forward to telling you all about my improved performances

[Scaredy Cat]

Hey Wayne good to see you didnt take it to heart ;D Another 60hp could be handy but im pretty content for now! You should check your hull for water, you never know. When is Ausfish week???

I know Wayne does get a little water in the hull, I think it was also coming from leaking spin outs, the boats got a pump in each side from the previous owners.
Installation of pumps would also help in the event of fat friends breaking the covers :-/

[Dean1]

Yeah I thought about pumps, put them in my last cat but it had weepholes that allowed the complete hull to drain to the rear.

I have 4 spinouts in my floor now that ill regularly check, drilling into the forward bulkhead is neccesary tho or you dont know whats sitting in the other side. 1 spinout accesses 2 bulkheads, i didnt link them all up so as they still act as seperate bulkheads, just bigger ones.

And I cant believe Kevlacat installs those cheap plastic spinouts from new, their rubbish and the use of ally or stainless should be normal practice.

Kevlacats built to survey require access to all bulkheads, which makes sense, i may even put 2 up the front near the seats as I have not check all bulkheads, tho I put one in the storage hatch up front and drilled back to the rear and they were dry. Theres 9 bulkheads all up, its nice to know that they are all nice and dry ;)

[termi]

Make sure your spinout has some sort of sealant where they screw to the floor,as mine didn't. Also put vasaline on the threads of the lids, you'll find this will keep most of the water out.

[fromeo]

A quick note just to let you know that all is now as it should be , put 15K Yami Props on and wow did the Boat come alive Top speed 28knots into a 30knot southly across Botany bay at 5400..5500 RPM WOT so the combination of 2 3/4 inch between the hull bottoms and the cavplate and 15K Props are definatly the way to go with FT60's.
A Very Special Thanks to Deano and Ian who took the time over the phone to give me advise and point me in the right direction ... Ps it also helps if you TRIM the motors way out to make those props work and get those big rooster tails happening .

[finding_time]

Great to hear Fromeo! Those 14's just must have to much cup. Now the fun begins and tinkering starts with trim to make the boat go even better ! a LITTLE TRIM MAKES A HUGE DIFFERANCE! Have fun!


ian

[Mr__Bean]

Just try to remember it is a boat, not an aircraft.

It is meant to spend some of its time in the water.

I am not sure Ian has fully grasped that concept.

- Darren