4.5 Porpoising

[BGG]

I've just taken delivery of a 4.5 Side Console with a 60 Honda on the back. All it wants to do is porpoise. And yes, fully trimmed in it still porpoises.
Has any one had a similar experience?

[Gravy]

I've just taken delivery of a 4.5 Side Console with a 60 Honda on the back. All it wants to do is porpoise. And yes, fully trimmed in it still porpoises.
Has any one had a similar experience?

Have noted my 4.1 Tiller Steer with 50 Etec also has a slight tendency to do this. Still evaluating as only had the boat on the water once, believe it could be related to a full forward live well or my unfamiliarity with trimming the boat.

Gravy

[PerfectPoly]

try changeing motor height and prop, if no luck u may have to get a hydro foil or chuck to deep cycle bats up the front.

[bushbeachboy]

I fitted a Permatrim to mine. Fixed the problem immediately.2thumbsup

[Dave]

HI BGG and welcome

Porpoising is usuallly due to the weight distribution in the boat, motor height and sea conditions.
A boat may porpoise in certain conditions but should not do it all the time as you suggest.
If this is the case, check the motor height.

You can adjust the motor height yourself, all you need is a trolley jack and a couple of correct size spanners.
Take the weight of the motor with the trolley jack
Remove the two bolts that are in the fixed holes.
Loosen (but do not remove the bolts in the slide adjustment holes.
Move the motor up or down, depending on current location. The plate should be approx level with the skeg (bottom) of the boat.
Tighten bolts and replace the removed ones.
Lower jack.

Test on water and check for results. Further refine position.

Once you are happy with the position, you will have to remove the bolts and put silicone in the holes to stop water ingress. If you dont do this, the water will seep into the hull and you will have the space between the hulls constantly fill with water. Dont use the silicone until you are happy with the position as it just makes it harder to work on. Keep in mind when you put it in, that there will be water entering the hull so make it a test run. If you live a long way from the water, take the trolley jack and silicone with you to the ramp. That way you can finish the job and then go for a fish.

If you are not entirely happy with the response of the boat in moving the motor, then seriously consider a permatrim or similar. It does provide better performance due to the weight of the boat and the power of the the motor.

Let us know how you go.

[BGG]

Thanx Dave
I might start with the dealer and see what he has to offer first. I've fitted motors before and the height/set up of this one looks OK.

[poly]

I fitted a Permatrim to mine. Fixed the problem immediately.2thumbsup

Yep, i have one as well and it fixed the porpoising, but it cause cavitation in tight turns
doh Paul doh

[DvrDve]

guys
havent tried it yet but the sx trim tabs some members swear by

[poly]

guys
havent tried it yet but the sx trim tabs some members swear by

Hmmmmmmmm if i were to start again to fix a porpoising problem, that would be my first choice.

Paul

[bbayjohn]

My 5.3 used to porpios. i have two bateries electric motor and fishing gear up the front. Changed the prop to a 4 blade and no more problems.
Permatrims can be dangerous. Check corect proping and motor hight first

[Andy]

As I said on AF, get some photos from the rear of the boat in line with the keel. The poly is tricky, as it does not sit like a normal boat and the bow sits quite high when they are trimmed correctly on the plane. I looked at the picture you put up on AF and i reckon the motor might be a fraction to high.

As also stated by Dave, weight distribution plays a big role in the hadnling of the boat. I spent a while playing with mine to get it right. I filled the arse end of mine with water by reaching out very carefully and loosening up a bung (dont let go of the bung!!). Tried a little weight in the rear, to a lot (water up over the floor) and found weight in the back was the best. I use my boat in moreton bay, typically in 0.5 to 1.5m chop, but sometime bigger, so conditions will also play a role in weight distribution.

[Rod]

BGG I have a 4.5 sc had the same problem. 60HP yam on the back. I have fitted 5 degree motor wedges and the boat planes flat with two people siting in the back. Fitting the wedges forced me to lift the motor one hole. Fixed

[PerfectPoly]

rod is right i have wedges in back to, and mine rides fine and i can sit 3 down the back.

[BGG]

Thanx all. It's back with dealer so I'll let you know how it turns out.

[BakerBill]

BBAYJOHN, "permatrims can be dangerous". I have one fitted and am wondering what you meant by your comment. It has greatly enhanced my boat which cavitated a fair bit when the motor was new. Since fitting the permatrim it has totally fixed this issue as well as having other benefits. The only thing I find in certain conditions it can leave the boat tilting as a plane does coming out of a corner. I fix this by steering out of the lean. I intend to fit SX Trim Tabs when my minister of finance okay's the project.

[chin]

I think the Permatrim works pretty well on Poly hulls because they have the reverse chines which prevent the boat leaning over while on the plane.
There have supposedly been some negative effects on other brand hulls, but it just seems to work well on my boat anyway.

[Pirate Pete]

I also believe that it's the wing style that stick out the side of the cave plate where one comes out of the water in a turn & then looses lift & makes the boat misbehave.

[BGG]

The dealer fitted a 5 degree wedge which made an enormous difference. I've also fitted a permatrim which has made the performance not just great but fantastic. This rig really punches well above its weight.
As for the new 60 Honda, I keep re-checking my figures because I can't believe the economy I'm getting and I'm still running in. Once I get a few more hours up I'll post the consumption figures.

[BigFella]

Some interesting reading in this thread!
Great to see all the different opinions on handling and boat set-up!
Polycraft are a unique brand in how they come out of the mold is unpredictable!
I have been paying particular attention to the hulls when they come down and you really need to fit up each boat individually!

Unlike quintrex, Allycraft, tab, Stacer or any other mass produced alloy boat where the parameters are often within millimeters of each other!

Some boats come out with whats called a "rocker" and some have a "hook" now these characteristics are mainly restricted to the last third of the hull's planning surface! I have seen some that had both, now that was hard to counteract as each side of the boat was responding differently!

Now what you see on the trailer may not be duplicated in the water either?
The very characteristics of "plastic" that we have come to adore can and often is working against all known theory's on boat handling and boat set-up!
Thats why it's paramount your dealer is "familiar" with Polycraft boats!

Trim Tabs, Hydra-foils, Permatrim, Solas Lazer-foil all have there place and one may perform better than the other but mainly it comes down to personal choice!

Stay Premium Gentlemen!

[BGG]

BigFella
I totally understand your comments. I"ll happily accept the differences between different boats if they perform the way they do. I've owned many boats from 3 metres up to 8 metres and now I'm just a poly convert.
LONG LIVE THE POLY

[Pirate Pete]

Glad to hear that you have your poly worked out BGG.

They a top little boats but do seem to need a little extra to get them set up.

I have found that my 5.3 doesnt seem to be effected too much with a load. I quite often fill the front bin in my cuddy cab & use it as a live tank when I fish & she still trims out & runs without any problems.

I have had thoughts of fitting trim tabs due to the fact that the "orphan" likes to sit at the rear on the leeward side of the boat & this makes it lay over to one side. As we dont run very far on most trips I havent worried about it.

[BigFella]

BigFella
I totally understand your comments. I"ll happily accept the differences between different boats if they perform the way they do. I've owned many boats from 3 metres up to 8 metres and now I'm just a poly convert.
LONG LIVE THE POLY

Thanks BGG,
I wasnt having a shot at anybody. Rather just trying to say owning a poly boat is a world of compromise! I wouldnt have any other boat, well other than a 24ft Tri-Toon with a 200HO Etec! But thats another story!