Many thanks Mark. I think you are right, the paint layer on the right mark must be gone and the grey is the next layer. I'll try to source a...
I just took my 17.5 ft fishing boat out for engine service anti fouling etc.. While at the marina one of my fenders got lose and mid port side of...
Rick many thanks for that, you are right the 2.21 gear reduction will deliver 1629rpm at shaft not 1689, typo by me. Given the engine...
I recently installed a new inboard diesel engine 3YM20 21hp yanmar on my boat. Max rpm is 3600rpm at the crank and 1689rpm at shaft. Displacement...
Hi, I have a small boat 18ft with an inboard diesel but want to mount a bracket for an auxiliary 4hp probably 25-30 kgs directly on the back of...
Joakim just to clarify the data I give on the old prop was the best info I had from what was stamped on the prop, however when I spoke to the...
Thanks for new data Joakim, I spoke with an experience prop shop in the UK and they are recommending a 14X11 prop, so I think I'm just going to...
Thanks Joakim for all your help. I'm going to trial a 13" and increase the pitch to 12 and see how I get on. That is a very comprehensive book...
Frosty found it hard to gain anything from that link , appeared to be relevant for a gas engine not inboard diesel set up. I think 9 diameter...
Joakim from what you said I would read it that 14X10 might be best option then 14 X 11 ? More of concern is I only currently have 2.5 cm (1 '')...
Thanks Rick that's a bit more encouraging, I'll talk to the prop supplier also to get their advice on the prop size they would recommend. Paul
Joakim thanks for that, the stamp on the old prop definately says 12.78 and I measured the diameter and its very close to 13'' so that metric...
Rick, it's about 1400kg fully loaded
Joakim Prop calc application from Castle Marine suggests best prop is : 1. If full displacment hull 13.34 X 8.68 2. If Semi displacement...
I have a small boat with inboard board engine which I am replacing with a new Yanmar 21 HP , 3600 rpm, reduction ratio if 2.21. I have to change...
On a small 18 ft with inboard, I have just installed a new Yanmar 30YM20 (21 MHP) 16 kW at max 3600 RPM , gear ratio reduction is 2.21 giving...
Thanks Par, at least I know now and maybe down the line I'll put a larger engine in to get her to plan. Many thanks for your feedback. I need to...
Determining Hull Type: more photos Please see attached more profile and stern photo's which will hopefully give me info on whether she is...
Thanks Par I used her for near shore fishing , but with new engine was hoping to get out into the bay a bit quicker, putting in anything over...
Thanks Tom, that's useful, I'll post a clearer picture tomorrow if I can get out to the boat which will make it much easier to read.
