Advice on Trim Fins and 4 blade prop

[CHunter]

Hi there,

I've got myself a boat that I will use 90% of the time on the river, cruising, kids skiing and a bit of fishing but every so often I'll hit the coast to catch a real fish.

It's a Quintrex 570 Freedom Cruiser with a 3.0 135hp Mercruiser sterndrive.

At very slow speeds, particularly with extra passengers in the rear seats, it wallows along with the nose in the air, is difficult to steer effectively, and is fairly uncomfortable - especially for the wife whose glass of wine tilts over!

I've been looking at the Nauticus SX9510-80 Smart Tabs 80LB as an option and wonder what others have found with this option? It seems I do need something to assist a bit to keep the boat trimmed up a bit better. I've also looked at the Permatrim but a not sure it's the right solution.

I am aware the motor is at the limit relative to the length of the boat with regards the hotshot, however what impact/benefit will a 4 blade prop give me?

I'd appreciate any thoughts with solutions that mean I won't have to sell a child to pay for them!

Ash

[scottar]

I didn't find I gained that much lift from a 4 blade. Depending on the efficiency of your existing prop, you may get lower slip with a either a 4 blade of a large surface area 3 blade but I suspect you will be better served with either the permatrim or tabs. You would need to calculate your prop slip ant talk to someone to try to ascertain whether it is prop slip that is your issue or simply weight distribution and not enough ponies. I run a set of trim tabs and a permatrim on my rig to give transom lift at slow speeds. I haven't used the nauticus system but being "fixed" apart from initial adjustment doesn't really appeal personally. I have run various foils on my alloy boats without issue and if after a cost effective option, that is the way I would go. If you are after the best option - a set of proper trim tabs though a bit pricey is bloody hard to beat as well as having benefits over the other options.

[TheRealPoMo]

Solas recommend a 4 blade when I chewed the old 3 blade up on my Volvo V6 for that reason. It did lift the back a small amount but not enough to plane at as low a speed as I would like. It is trimmed pretty much all the way in except in glass at 20 knots plus. Trim tabs too expensive to fix an issue I can live with. Maybe more weight up front....90 litres of fuel up there might help.
WOT speed fell from 45 knots to 42 but 20 to 28 is the sweet spot anyway. Holeshot....maybe better but not a concern for me.

[bigjimg]

I fitted a Stingray XR111 foil to drop the nose of my rig while towing the kids. It was fitted to the 135 Opti in less than 15mins once all the tools were gathered.
It worked an absolute treat and would plane the boat at 10 knots.

Unfortunately on the last trip an object went through the prop and didn't make a noise enough for me to hear or feel but the foil was damaged substantially.
I only just fitted up the Permatrim yesterday and was $100 cheaper than the Stingray. $230 delivered.
A foil is a cost effective solution and will make a difference. But a lot longer to install the Permtrim and holes to drill....Jim.

[bigjimg]

Just fitted up a Permatrim only yesterday.
I had a Stingray XR111 that was substantially damaged on my last trip by an unknown object.

The Permatrim at $230 delivered was $100 cheaper than the Stingray.
Hopefully the Permatrim will continue to deliver the same performance as the Stingray or near enough.
The boat is flat at hole shot and would plane at 10 Knots while towing the kids on the tube. Which was my reason to install in the first place.
I swing a 17in 3 blade Vengeance prop.Jim

ps. In case everyone is wondering why 2 posts the first one disappeared and was lost or so I thought..........

[Duckfish]

Ditto to bigjimg. You'll get more effect from a foil then a prop change. My two bobs worth.
Duck

[Lovey80]

I recently went through this on my Webster 4.3CC after a serious amount of mods. The ass was sitting tow low and taking too long to plane if I didn't have the front casting deck full. The [permatrim] made a dramatic benefit. So much so that I began spinning off the rev meter at WOT and had to re-prop the boat accordingly. The performance now is so much better with the foil.

[gofishin]

Ash, it depends a lot on the design of the prop, whether 3 or a 4 blade, as to how much transom lift you get. Generally you will get more transom lift out of a 4 than a 3, and some 4's provide a lot more than other 4's.

I had the same issue with my previous boat, a 610 Freedom Sport, although mine was O/B powered so I also had the benefit of more bow down as I lifted the motor with additional mods/improvements/changes.

Great day boats, but as the seas got lumpier people tended to move aft, where the bumps were smother, but this stuffed the trim - as you are finding.

I had 9x9 tabs on it from the get-go, but they did not do the trick when all crew were down the back. Installed a Permatrim and this was fantastic. Sold the boat before playing with 4 blades on it, but helped the new owner get a good SS 4 blade, and he reported that the boat was even better again (flatter trim, lower min planing speed, and better economy).

I would start with a Permatrim, and if not enough look for a suitable 4 blade with a low P/D ratio, and not too much rake. SOLAS can help there, however you might find some good 2nd hand ones on evilBay.

If money is left in the kitty after above, go for trim tabs - proper ones though, not the ones you mentioned. These would actually be the first thing I would go for, but your usage pattern (and limited budget) mean you could get the other 2 for way less than a good set of tabs.
Cheers
Brendon