Porpeller

rag&stick I don't have trim tabs fitted, it is something I have thought about but am going down the prop route first, I am definitely over-propped and that needs sorting. If I continue to have issues I will look at tabs

Billy Looking in the official Mercury book with the dealer there are a loads of props that will fit on my engine the 16" diameter being the largest that will go on

Good bit of advice from Bennetts Trim tabs:

Using Your Power Trim and Trim Tabs Together

It is a common misconception that if a boat has power trim on the outboard or outdrive it does not need trim tabs. Yes, power trim can be used to adjust the boat’s attitude, but it is highly inefficient.

This is because a propeller is designed to force the boat forward. When trimming the boat with the prop, the prop must not only push the boat forward but raise the stern as well. In this situation, prop slippage is greatly increased thereby wasting RPMs. Power trim also cannot correct listing, and is ineffective at slower speeds.

For increased speed and power, use your trim tabs WITH your power trim. Bennett Trim Tabs, in combination with power trim, enable both the hull and prop to be trimmed independently. The trim tabs trim the hull, while the power trim adjusts the prop. The result is optimum performance and efficiency not attainable by the use of power trim alone.

To achieve maximum performance:
1. Adjust the trim tabs to achieve a planing attitude.
2. Use the power trim to position the prop path parallel to the water flow.
3. If necessary, re-adjust the trim tabs to “fine tune” your tabs. In other words, use your trim tabs to trim the boat and your power trim to trim your prop.

Just a bit of an update on the prop, We decided to go for a 15" pitch in the end.

The result being another 1300rpm (topping her out at 6000rpm) which is bang on the limit for a light clean boat (our calculations have worked out she should drop to roughly 5500rpm when I'm loaded for fishing)

Gained another 3kts so now get 27.5kts WOT. More importantly my cruise rpm is 4100rpm but this comes at a lower throttle setting so should see a small reduction in fuel consumption, roughly working out at 20 l/ph down from 24 l/ph