Trim setting - Brig 500L

[wonky]

Does anybody have a Brig 500L and find that it naturally rises bow high?

I have a Yamaha 50 and it’s trimmed all the way down, but when a passenger stands next to be at the helm the stern sinks and it comes off the plane. I can up the refs and get it back on the plane, but not within the speed limit in Poole harbour .

Any thoughts on solutions / similar experiences would be much appreciated.

Thanks

[midlife]

Trim tabs worked a treat on mine

[wonky]

Ah, not a bad idea. What ones did you go for?

[Jojosrib]

Originally Posted by wonky

Does anybody have a Brig 500L and find that it naturally rises bow high?

I have a Yamaha 50 and it’s trimmed all the way down, but when a passenger stands next to be at the helm the stern sinks and it comes off the plane. I can up the refs and get it back on the plane, but not within the speed limit in Poole harbour .

Any thoughts on solutions / similar experiences would be much appreciated.

Thanks

This happened on a 5 m rib that I had a while ago. Fixed with wedges on the transom.

[The Black Pig]

Originally Posted by wonky

Does anybody have a Brig 500L and find that it naturally rises bow high?

I have a Yamaha 50 and it’s trimmed all the way down, but when a passenger stands next to be at the helm the stern sinks and it comes off the plane. I can up the refs and get it back on the plane, but not within the speed limit in Poole harbour .

Any thoughts on solutions / similar experiences would be much appreciated.

Thanks

Does that happen every time you go out Wonky?

[Iankristy]

What’s the speed limit in Poole harbour?

[Limecc]

Originally Posted by wonky

Does anybody have a Brig 500L and find that it naturally rises bow high?

I have a Yamaha 50 and it’s trimmed all the way down, but when a passenger stands next to be at the helm the stern sinks and it comes off the plane. I can up the refs and get it back on the plane, but not within the speed limit in Poole harbour .

Any thoughts on solutions / similar experiences would be much appreciated.

Thanks

This could be a design problem then. Our caravan neighbour on holiday had a brand new Navigator 485 which looks like it has the Falcon 500 tubes that have been shortened by removing the pointy bits (sponsons?).

Fitted with a Suzuki 40 it was running so bow high and low at the stern, following and observing him (+ wife) within Salcombe estuary speed limit I thought water was going to go in over the transom. It didn't look balanced.

[Fender]

Originally Posted by Iankristy

What’s the speed limit in Poole harbour?

most of poole is 10knts, my rib won't plane at that - it'll sit on the hump and make lots of noise but not get out of displacement mode, we just run at 7-8 and enjoy the day till out of the harbour

[Iankristy]

Originally Posted by Fender

most of poole is 10knts, my rib won't plane at that - it'll sit on the hump and make lots of noise but not get out of displacement mode, we just run at 7-8 and enjoy the day till out of the harbour

That’s what I was getting at. Brigs May well be a bit back heavy I don’t know but either way hoping to plane sub 10 knots is optimistic. If it runs well and planes nicely at a reasonable speed then no action required. Chilling out seem the way to go [emoji41]

[jonp]

Wow that doesn't sound right, are you sure the engine is fully trimming in?

You can purchase outboard transom wedges which allow for more trimming in.

There are also self levelling trim tabs which are quite inexpensive and easy to fit yourself. I would recommend using the smallest bennetts self levelling trim tabs, these can be setup at three different settings of pressure and would certainly bring your bow down.

[Locozodiac]

Is the 50 Yammie a manual or electric trim motor powering a central console rib ?

Happy Boating

[midlife]

Originally Posted by jonp

Wow that doesn't sound right, are you sure the engine is fully trimming in?



You can purchase outboard transom wedges which allow for more trimming in.



There are also self levelling trim tabs which are quite inexpensive and easy to fit yourself. I would recommend using the smallest bennetts self levelling trim tabs, these can be setup at three different settings of pressure and would certainly bring your bow down.

They worked on mine

[Last Tango]

I'm going to guess anything "fixed" that gets you on the plane at 10kn is going to cause problems at higher speeds. The only thing cheap enough and easily removed if it doesn't work, (ie no holes in your transom) is Doel fins and dependent on the engine setup they might cause problems at higher speeds.

[jonp]

Originally Posted by Last Tango

I'm going to guess anything "fixed" that gets you on the plane at 10kn is going to cause problems at higher speeds. The only thing cheap enough and easily removed if it doesn't work, (ie no holes in your transom) is Doel fins and dependent on the engine setup they might cause problems at higher speeds.

Not necessarily, the slt tabs also work at speed without any adjustmeant, most of the time improving handling and fuel economy. The only real downside is reversing at speed but with extra trim up this is soon overcome.

https://m.youtube.com/watch?v=vJjImrGFd04

[jonp]

I've also used this brand before without any complaints, personally I've found the smallest more than enough. There are some for sale on the world fishing forum, new for £80 https://www.worldseafishing.com/foru...#post-48331769

https://m.youtube.com/watch?v=rQub7Q_1Euo

[Last Tango]

Originally Posted by jonp

I've also used this brand before without any complaints, personally I've found the smallest more than enough. There are some for sale on the world fishing forum, new for £80 https://www.worldseafishing.com/foru...#post-48331769

I had exactly the same boat as the SeaRay in the video with a 4.3LX 205hp Merc for 4 years and the only way it could be made porpoise like that was by badly over-trimming the drive. That boat has absolutely no requirement for trim tabs which makes me a bit dubious about their claims.

https://www.youtube.com/watch?v=VDq90lmK9tc

Similarly with the Boston Whaler the outboard is plainly trimmed wrongly to create the bow up issue.

I'm not dissing their potential benefits if there is a problem with trim but the OP is trying to get his boat to plane at 10kn so the issue has more to do with his expectations rather than any failing with the boat.

[Locozodiac]

Wonky,

Why would you like running a Rib fully trimmed up or down when both motor and boat manufacturers sates on their Owner’s Manuals how you should ride a boat powered with a motor. Check pic...

My Boating Club has installed new Yams and Tohatsu HP motors on different size Ribs recently and would be most pleased to help you out with a new motor optimization for spot on water performance if that’s OK with you ? If so, as a starter would need to know if the motor is a clamp or bolt on transom model to go from there…

Happy Boating

[jonp]

Originally Posted by Last Tango

I had exactly the same boat as the SeaRay in the video with a 4.3LX 205hp Merc for 4 years and the only way it could be made porpoise like that was by badly over-trimming the drive. That boat has absolutely no requirement for trim tabs which makes me a bit dubious about their claims.

Similarly with the Boston Whaler the outboard is plainly trimmed wrongly to create the bow up issue.

I'm not dissing their potential benefits if there is a problem with trim but the OP is trying to get his boat to plane at 10kn so the issue has more to do with his expectations rather than any failing with the boat.

I've used them on the last five boats I've owned and found improvements in exactly what the manufacturers state. However I did try a set of the smallest bennetts on my current 550 pro where I found no noticeable difference in performance at all. My zodiac handles very well, what I was trying to achieve was even better results by reducing less drag by raising the tubes higher with more stern lift. The stern did lift marginally but there was no worthwhile improvement so I removed them.

I honestly believe they would greatly improve the boat in question but my question is why does this boat do this, sounds like a poor design or simply some issue where the engine doesn't trim correctly. After a conversation with a major propeller manufacture, who stated small boats that need aftermarket tabs are poorly designed. I also use my own judgement from experienceing something rather by how something looks.