Changing propeller size for Salmon trolling

[Georgevb]

We purchased a C28 and enjoy cruising and Salmon fishing.

The engine is a Yanmar 6BY2- 260 and has a trolling valve to assist in reducing the boat speed at idle. Unfortunately that feature also works like a clutch and will wear it down after significant use; we fish a lot.

I was wondering if anyone replaced their factory prop with a different pitch prop, allowing the idle speed to be lower and minimum impact to the top end speed.

Thanks

 

[baz]

I've been told it will take a long time for the clutch to be compromised with extended use of the Low-speed mode on my 300 HP Volvo Penta.

 

[Georgevb]

Thanks,

Our boat is a 2011 and the previous owner fished a lot also, so the adjustment for trolling is not so easy to get set right. We will contact our local prop shop to get the right size prop.

 

[baz]

Thanks,

Our boat is a 2011 and the previous owner fished a lot also, so the adjustment for trolling is not so easy to get set right. We will contact our local prop shop to get the right size prop.

It does take practice to get it right.

 

[kelpline]

We have a 2011 Cutwater 28 with the Yanmar 6BY2-260 and fished salmon in 2020. Our trolling valve did not engage, so we have to troll at 3 knots or so. First we tried towing a bucket to slow down. Then we lengthened out our tails behind the flashers to 72", and easily caught our annual (Canadian) limit of 10 chinooks. This winter I found a 19x18 three blade prop with the right shaft size and taper for $300 on craigslist. We had to make a steel prop puller for the 4 blade, then fire up the tiger torch to get it off. We are splashing the boat soon, but the areas inside Vancouver Island are closed to sports fishing until July 1 or 15. So its cruising, e biking and prawn fishing for a couple of months (tough life). I'll give a report in August when fish show up.

 

[Georgevb]

Update - I was referred to the prop Shop in Mukilteo and they said they have a process for modifying propellers. They do it all the time.

They asked me about my boat size, how many blade prop I had, etc. and also how much reduction in speed I was looking to get at the low end. I let him know i need to reduce my speed by one knot. They can do that by sizing down my propeller a bit and not cause the engine to over rev at the high end.

Will let you know how that works out.

 

[bob daily]

I have a question for you, have you dropped your trim tabs fully while trolling and seen any difference in speed? Was just wondering would be nice to know! Bob

 

[bob daily]

The reason I asked the question is I've been looking at Nauticus Protroller - trolling plates and trim tabs all in one! They say with the trim plate detractors kit (about $50) you can turn any trim tab into trolling plates to reduce your speed by about 40%. The one draw back is you have to be able to reach the detractors from the boat, but compared to the price of a trolling valve I'm sure that can be figured out! Just dreaming about my next boat. Bob

 

[baz]

Update - I was referred to the prop Shop in Mukilteo and they said they have a process for modifying propellers. They do it all the time.

They asked me about my boat size, how many blade prop I had, etc. and also how much reduction in speed I was looking to get at the low end. I let him know i need to reduce my speed by one knot. They can do that by sizing down my propeller a bit and not cause the engine to over rev at the high end.

Will let you know how that works out.

Well done. The Prop Shop in Mukilteo is excellent. I had two of my 4 prop blades slightly bent on their tips after colliding with a log. The Prop Shop repaired my bent prop tips without any fuss and for a reasonable price.

I hope your new prop does the job for you, and ask that you post back saying how the new prop allows you to go at a slower speed for trolling. Thanks.... 🙂

 

[kelpline]

Update on our 3 blade propeller: the engine ran faster (about 200 rpm), and cooler, but it flutters a bit. So we changed back to the smoother 4 blade. Fishing was not so great this summer, chinooks were hard to find up where we fish in Blackfish Sound.

 

[knotflying]

My only comment/observation is that the prop is usually sized to achieve proper RPM under load. I am not sure how changing the pitch will affect the RPM on the high end and over rev when trolling is not required. Wouldn't adding a small HP kicker provide you the slow trolling you require, hence leaving the engine configuration the same.