Solas prop

[MerryFisher]

I've got a Yamaha F115 with standard 15P alloy props. It performs adequately under normal load, however when I have 4 or more people on board it slips a bit and takes much longer to get on plane. I've been looking at Solas Saturn of the same size and pitch. Would this give a better grip than the stock alloy one?

[dunc333]

it will perform better than the alloy prop you have and if you had prop slip it sounds like your prop hub was stuffed.

[MerryFisher]

It could be the prop hub, however it's a new motor and prop so I don't think it's a likely case. I've tried the 17P prop as well, got a higher top speed but took forever to get on plane due to prop not having enough bite.

[GoingFishing]

Hi Mate

What boat is the outboard fitted on? The addition of 1 or 2 additional people (say 150kg total or 75kg average) shouldnt change your outboard performance so vastly. 

Changing prop can enhance and tweak your boat performance but it sounds like you might be underpowered......

[MerryFisher]

It's on a 6m glass boat. It does sound underpowered, however 115 is the stated max horsepower by the manufacture. With 15P prop it performs well with up to three people, cruise at 20 knots around 4500 rmp and max out at 30 knots. I feel like the issue is not power but a lack of grip by the prop as the acceleration around 10 knots before jumping onto plane is slow with a heavy load. With a 17P prop it becomes revs get higher with very slow speed increase before planning. The boat is a merryfisher 605 by the way.

[Fishop]

Id call solas and see what they say.  Ive heard they are good at matching up props with engine/boat combos.

Your prop must be larger than mine as I have a 5.6m glass boat with a 90hp and 16p prop.  Props stainless though.  I get similar cruise and wot speeds/rpms as you.

When I called them they suggested a 4 blade.  Down a pitch but due to the 4 blades you get more bite.  They said their alloy props are almost as stiff and strong as the stainless ones these days so that should save you a few hundred bucks.

[GoingFishing]

I just had a look online and the stated hull weight is 1440kg.......

Seems very odd that the manufacturer has such a low max HP for such a heavy hull. 

For comparison my hull is 6.2m and 980kg with max HP of 150Hp.

Id also explore another option such as hydrofoil for your prop. Im not an expert but ive heard some models help with getting boat on plane and balance. Others might know more on hydrofoil

[PaddyT]

Go prop before foil, foils have there own problems- but gee's that boat sounds way underpowered.

[zmk1962]

Since I was not familiar with a Merryfisher 605 I had a quick look at the hull and specs ... this is what I found: 

So hull is 1080kg and laden with 4 crew plus gear you're in the 1400-1600kg payload weight - pretty much what @GoingFishingposted. 

Looking at your hull configuration with the full half cab design, it suggests to me that when you have 4+ on board they all tend to stand/sit behind you - so you are very stern heavy - which would throw out your hull dynamics and hence contribute to a longer time to get on a plane. I had similar issues with my Haines 635L half cabin after installing the following at the stern: Auxiliary (50kg), live bait tank (35kg), 3 x batteries (60kg), 10L oil tank (10kg) etc.  Then adding all the crew who undoubtedly prefer to sit out in fresh air on the seat across the stern - it is the softest ride in a chop after all !!!  No one likes to ride in the cabin (it can also be dangerous in a chop).

Given you are restricted to a max115hp motor, consider the following options:

1) weight distribution to improve the balance : Get the 4 crew to move forward and stand next to or directly behind you. This will be a quick, no cost way to confirm if its balance related and to see if you are back to your previous hole shot performance. Also, get some mates and experiment with them sitting forward in the cabin as well - note where they are sitting and how the hull behaves for hole shot. 

2) If your test shows its balance related: and you want a cheap solution - make sure all your gear is stowed as far forward in the cabin as possible. Consider putting a counter weight as close as possible to the bow  (I installed a 100L fresh water bladder under one of the bunks) - depending on where the center of gravity is on your boat - 100kg at the front may counter balance 150kg+ at the stern - noting where you mates were sitting will also be a good guide. A bit of extra weight at the bow helps the ride cutting through chop (but the trade off is you are pushing around more weight all the time). I also installed an anchor drum winch (50kg) which is mounted right at the bow for other reasons, but its proven a great permanent counterweight.

3) Install trim tabs or similar on the stern - to help lift the boat stern at lower speed. 

4) Install foil on motor - similar effect as trim tabs (but like @PaddyT said - they have problems). 

By all means experiment with the prop to get more thrust - but I would suggest having a go at weight distribution with the current motor/prop set up first. 

PS - given what you have described, it does not sound like you have blown a prop bush that's giving you prop slip (especially if you have not hit anything with the prop).

Cheers

Zoran

Edited October 11, 2018 by zmk1962

[PaddyT]

) Install trim tabs or similar on the stern - to help lift the boat stern at lower speed. 

 

Agree with this, trim tabs are a far better option than a foil, personally i'm amazed that he even gets that boat on the plane

[Fishop]

Exactly what zoran said.  My boats a pig when everyone ones to hang out in the back.  Its hard to convince people to sit/stand up front especially when its choppy.    I noticed minimal differences with a foil on mine. Next step is trim tabs and moving weight forward like batteries and the esky.   Someone on a facebook page even said he put 150kg of lead up the nose of his boat to help with weight distribution!!

[MerryFisher]

Thanks for the suggestion guys. When I had 4 adults and 2 kids on board the seating configuration goes 3 adults in the cabin, 1 adult and 2 kids at stern for the majority of the trip. At times I had everyone except 1 adult in the stern and it did not make much difference in the times it took to get on plane. I can rule out weight distribution as most of time no one sits at the stern in my boat, as the enclosed cabin is a lot more comfortable that's protected from the elements. I think I will try a 4 blade prop as suggested, as it sounds like the most economical solution. Anyone know if Solas Amita 4 is a good option? 

Edited October 11, 2018 by MerryFisher

[MerryFisher]

Here's a diagram of the seating configuration. Blue dots are adults, red are the kids, they move around.

Edited October 11, 2018 by MerryFisher

[jeffb5.8]

See what your selling dealer recommends and maybe they have a couple of different props you could try and also give Solas a call.

im sure your the not the first to have this issue.

 

p.s

nice looking boat

 

[zmk1962]

Yup... as @jeffb5.8 said I'd be giving the dealer a call.  They should be able to tell you at what speed the hull should start to plane, so If you are within your max crew capacity rating, and you are comfortable the balance is correct, then its pretty well thrust related.

You are limited to the 115hp, so experimenting with higher thrust (lower pitch) props is a path forward. With lower pitch you will lose top end speed, but you will hit planing speed sooner.

One other thing occurred to me - have the dealer check your outboard height mount. If the outboard is mounted too high, you may be getting cavitation (ventilation) around the prop, which will affect your hole shot - this will be more noticeable with increased load. This could be why you are describing the prop as "slipping" - its actually cavitating so has reduced contact with water.

Cheers

Zoran

[GoingFishing]

Just for fun ill add..... 

Should have went 2 stroke.... ?

 

[PaddyT]

9 hours ago, MerryFisher said:

Thanks for the suggestion guys. When I had 4 adults and 2 kids on board the seating configuration goes 3 adults in the cabin, 1 adult and 2 kids at stern for the majority of the trip. At times I had everyone except 1 adult in the stern and it did not make much difference in the times it took to get on plane. I can rule out weight distribution as most of time no one sits at the stern in my boat, as the enclosed cabin is a lot more comfortable that's protected from the elements. I think I will try a 4 blade prop as suggested, as it sounds like the most economical solution. Anyone know if Solas Amita 4 is a good option? 

Solas know their stuff, every boat is different, usually they will allow you to swap props if the first one they send doesnt do what you want for free (your shipping expense) go on their advice over "dr google"

[zmk1962]

46 minutes ago, GoingFishing said:

Just for fun ill add..... 

Should have went 2 stroke.... ?

BAHAHA.... Sam Sam Sam.... I reckon that would be a great topic for YOU to kick off as a separate thread... and I'm sure Donna would let you start it only if you volunteered be a moderator to handle the extra posts and vigorous discussion !!! ?

Cheers Z

[mrsswordfisherman]

51 minutes ago, zmk1962 said:

BAHAHA.... Sam Sam Sam.... I reckon that would be a great topic for YOU to kick off as a separate thread... and I'm sure Donna would let you start it only if you volunteered be a moderator to handle the extra posts and vigorous discussion !!! ?

Cheers Z

Just for fun I’ll add NO. ?

 

[GoingFishing]

Hahaha sorry guys not trying to stir but we have to introduce some fun occassionally !!!!!

[mrsswordfisherman]

14 minutes ago, GoingFishing said:

Hahaha sorry guys not trying to stir but we have to introduce some fun occassionally !!!!!

Have fun often life is short Sam

[zmk1962]

Yeah but was the NO to the topic or to being a mod??? ? 

[zmk1962]

Hey @MerryFisher hope you postback with the outcome of your conversations with the dealer and solas. I for one am really interested in how this is resolved. Your hull looks like an awesome layout and it would be a shame not to have it performing optimally. 

BTW maybe this topic should be renamed to “Improving Hole Shot”.  A Solas prop is just one approach. 

Best of Luck. 

Zoran

[MerryFisher]

Will do, got a few days off next week, see if I can sort something out.

[rozza_b]

Dont bother ringing solas in aus they dont exist anymore, they went out of business in about june i think, the business has changed there name, cant for the life of me remember what to

Also as mentioned above get your motor height checked, motor to high could be causing cavitation but also if its to low with the extra weight it might be struggling to get up out of the water and onto the plane, this caused a issue on my boat.