Townsville....who can re-rate a hull's max HP?

[Scott nthQld]

Hi All,

As mentioned in an earlier post, I am in the process of rebuilding and old Cruisecraft Rogue 14 hull.

Anyway, back in their heyday, they were rated to a max hp of 60. Unsure of what weight though. Currently the boat has a 50hp 4 stroke on the back, and being one of the first lot of fourstrokes before they started getting popular, is weighs a ton, somewhere in the vacinity of 150kg if i remember correctly. Boat perfoms and sits well with that weight hanging off the back, but i was looking into upgrading to a few more ponies, now that the engines are lighter, I was thinking of putting at least a 70hp 4 stroke on the back as I'm a bit of a speed demon.

i haven't done it yet, but will be replacing the transom, and am toying with the idea of putting a full width pod to get a bit more bouancy in the bum end, especially since it will no longer be a runabout, front steer, unit, but a centre console, so this will hopefully counteract the extra weight further towards the stern, and the missing weight up at the pointy end.

Anyway, If I decide to go ahead and pod it my face lit up a bit when it dawned on me that perhaps i could put even MORE HP on her, and thought of chucking a 90 back there .

But anyway, does anyone know of anybody in Townsville, or even Cairns or Mackay, who can instruct/test/re-rate my hull to meet any possible new requirements? by instruct i mean someone who can recommend what i need to do, as in materials and methods I will need to use to ensure the extra strength I will need?

[STUIE63]

Scott try the fibreglasser on the left side of Pilkington st going towards the RAAF base just before the railway line . if he doesn't do it he should know who does

[Scott nthQld]

Thanks Stu, didn't even know that bloke existed.

I might have to send the bloke from Galeforce and email too, pick his brains about how he build his transoms with no timber....really don't want to use timber at all in this boat

[eugah]

Scott try the fibreglass mob accross the road from the bottle shop at the Queens road, Railway ave lights, they always have boats in there being repaired or modifed.


Adrian

[Camhawk88]

Yeah the guy at NuWave (Pilkington St) knows his shit. Not sure about the new one on Putt St- (FibreFinish?) but worth talking to both of them if nothing else to compare a price.

[ozbee]

scott most of the pods down here are made out of ally and then sandwich between fibreglass and matting, some dont bother and spray two pack. there is some strick mathematics to abide by to make a pod perform . a 90 is not a over kill . have a look at one of my workers boats has done exactly that and has a 90 honda on it

[thump-a]

P M sent

Cheers Graham

[Jarrah Jack]

Nick Lockyer can give you the correct certificate once the work has been done. He on the goldie but can do the work at a distance. It may be worth discussing it with him. He's at kpsmarine.com.au.

[Scott nthQld]

Tanks fella's.

If I can get it done its then only a matter of choosing an outboard. Narrowed down to 3 brands is the Suzuki, Honda or E-tec, all 90hp and all very similar in weight etec being the lightest, suzi another 5kg ontop of that, honda another 5kg or so on top of the suzi, and the honda is only 10-15kg heavier than the current outboard, so for an extra 15kg (max) I am gaining potentially 40 extra hp.

Just depends where I can get the best deal and service

[Moonlighter]

Just a word of caution: Are you sure you want to put a 90 on a 14 foot boat? Sounds overpowered to me. My previous boat, at 4.75m (15 1/2 ft) and with a wide beam, had a max of 90 on it, so a 90 on a 14 footer could really be pushing the limits!

The Australian Standard AS1977 specifies the formula that manufacturers (and presumably anyone qualified to certify boats) have to use to determine the max hp for their hulls. It says this:

Length of boat X waterline beam width at transom X 16 less 67 then X 1.34 =
absolute max hp you can use on your boat.

Then that result has to be verified as safe by doing a serious practical on water slalom test, at full throttle, through an on water course specified in the standard, including performing a 90 degree right angle turn at full speed also, within a prescribed distance, safely and without shipping any water.

If it cant do that, then the max hp has to be lowered and a new test done.

An example of how the formula works for a mythical 14 ft (4.26m) boat with a 1.8m beam at the stern (waterline level) is as follows:

4.26m boat X 1.8m beam at waterline at the stern =7.668 X 16 =122.688 less 67= 55.68 X 1.34 = 74.62 hp.

Maybe do some measuring of your hull and run the above formula on the actual measurements on your boat yourself before you get too far down the track.

Cheers
ML

[Scott nthQld]

yeah, boat is a bit wider at the transom at 6'6", about 2m roughly, will give me a bit more room to work, and i will only be putting a 90 on if i pod it, and it will be a full width pod, other wise a 70hp will go on, which will be well within that formula.

Weight wise though a suzi 90 would be better, its actually a couple kilo's lighter then the 70 due to being the same block, just bored out a little more I think.

It's not something I havn't considered, I've done the leg work and have found a couple of the same boats with the 90hp fitted, 2 and 4 strokes

Just going by that formula:

Boat Length 4.26m
Waterline Beam: 1.98m

4.26 X 1.98 = 8.4348 X 16 = 134.9568 - 67 = 67.9568 X 1.34 = 91.06hp

So in theory could chuck a 90 on as is

[oldboot]

I'd be scheptical about a 30% increase in HP.

It sounds like the realms of engineering reality to step from a 60 to a 70.

But I recon you are being a bit hopefull to go to a 90.

Have you had a chat to the boys at crusecraft, they may be able to enlighten you about the original design.
My understanding is they are very keen to have well restored old crusecrafts running arround.

If the boat was originaly a good thing ( well balanced ect) in its original form, doing a runabout to CC conversion AND adding a pod is realy going to push your centre of gravity way back.

My boat , an 14"( in reality) aluminium stacer, has had a pod fitted ( before or after manufacture I realy don't know), and I am doing a refit to try and move some weight forward.

Because no matter what you do as it was the nose stood up quite high getting out of the hole and over chop and waves it flew quite nose up.

The crusie crafts are known to be a sweet boat, be carefull you don't bugger up that balance.

As it is, I recon you need to make sure you get some weight ( tanks batteries)forward to compensate for what you have shifted back.

cheers

[Scott nthQld]

I'd be scheptical about a 30% increase in HP.

It sounds like the realms of engineering reality to step from a 60 to a 70.

But I recon you are being a bit hopefull to go to a 90.

Have you had a chat to the boys at crusecraft, they may be able to enlighten you about the original design.
My understanding is they are very keen to have well restored old crusecrafts running arround.

If the boat was originaly a good thing ( well balanced ect) in its original form, doing a runabout to CC conversion AND adding a pod is realy going to push your centre of gravity way back.

My boat , an 14"( in reality) aluminium stacer, has had a pod fitted ( before or after manufacture I realy don't know), and I am doing a refit to try and move some weight forward.

Because no matter what you do as it was the nose stood up quite high getting out of the hole and over chop and waves it flew quite nose up.

The crusie crafts are known to be a sweet boat, be carefull you don't bugger up that balance.

As it is, I recon you need to make sure you get some weight ( tanks batteries)forward to compensate for what you have shifted back.

cheers

Yep, taken everything into account already, fuel tank(s) will be moved as far forward as possible, seating arrangment, though skiper seat will be further back, in its original form, with the oldscholl back to back seating, you were already sitting about midship. Batteries will be moved forward to under the skipper seat, casting deck will be inplace, to make up for the weight lost for the runabout style front end, as well as underfloor storage. The boat currently is not fitted with underfloor tanks, rather a deck tank that sat right up the back of the boat, these used to be 2X 30L tanks, so that's another 50 odd kg being moved forward, plus an additional 40kg roughly with fuell carraige being raised to about 80-100L, depending what i can fit.

Boat sits quit ass heavy now with the current 4 stroke, but these engines, even the 90hp are the same in weight as the current 50hp (really old 4 stroke). i was goig to go with a full width/depth pod though that should give me a bit more floatation in the bum end as well....if done correctly that is.

under the future casting deck will be tackle lockers, as well as provision for a deep cycle battery for the bow mount, which will give me a bit more wieght up there as well. I've done all the sums, and currently I am about even with weight distribution, if not a bit more nose heavy than standard fitout.

I have already contacted Cruisecraft, months ago, and they weren't interested in anything, emailed me the old brochure (which is where i got max hp from as there is no plate on the boat) and that's about it. Upping the horsepower was only something that I only really started considering over the last few weeks, i was always going to go to a 70, but with the addition of a pod a possibility, i considered going to a 90.

[myusernam]

If you are modifying the hull that much just reregister it as a custom build and put whatever you want on it. (dont call it a cruisecraft) put yourself down as the boat builder.

Reckon you will ever do it? Or will this be another ford ranger/ buying a longboat thread that wil go for twenty pages and nothing will happen?

[Scott nthQld]

dunno if I'll put the 90 on, like I said, depends if i pod it, but yes the boat will definately get done, cos it's on it's way to my joint now.