Ok I should know but I don't so asking for advice

[MisterBaxter]

@Sea Hustler if you were in the mood for spending money, a feathering prop might be quite a big improvement for your boat. She'd sail a great deal better, given that she probably has quite a large prop for her size, being a motor sailer.
She might also be better in reverse, as some feathering props can be given a finer pitch in reverse, reducing prop wash and giving somewhat more responsive maneuvering.
But greatly improved sailing performance would be a certainty. Even a small propeller makes a big difference - I had a Sonata with a 4hp outboard and it felt like she was towing a bucket with the motor tilted down.
You could also get the right size and pitch of prop if you were changing it.

 

[oldmanofthehills]

You have been amazing, I have learnt more in these past few days about the boat than in the past 18 months. I have scoured T'internet for any information I can find on her but apart from some basic information on the Sailboat Data website, and an article about the designer, there is nothing.

The gearbox ration is written on the gearbox, the prop outside diameter can be measured ( i might guess 15 or 16 inch) and the pitch should be written on the prop. And you know the hp

So thats all you need to calc prop suitability

 

[westernman]

You can of course get a prop re-pitched. It was a lot less expensive than I was expecting when I did mine.

 

[William_H]

Not sure what blade and slot mount actually is but the mast is deck stepped into a U shaped upright and secured by two bolts. Strangely enough when doing some work on the forestay mount, I checked the two bolts and while both were secure through the foot of the mast, I was able to easily undo the nuts and pull both bolts (one at a time) out through the mast implying there was no pressure on them, not sure if that good or not.

This is quite normal in fact desirable that the bolt (s) through the mast base are loose. It means that all the down load of the mast is on the base of the mast itself. Not on the bolts. I use a 1/4 inch bolt in a 3/8 hole which gives me slack to allow for mast swing when lowering. In my case just one sideways bolt.
So the bolt is only to ensure base stays in place fore and aft (and possibly sideways) Just make sure it does not fall out. As Nigel says mast base location fore and aft does not result in much if any variation in boat handling. Blade mount is what my little boat has. In stead of U channel for mast to sit in it sits on a single up turn (blade) fitting into a slot in the base of the mast ol'will

 

[Refueler]

Not sure what blade and slot mount actually is but the mast is deck stepped into a U shaped upright and secured by two bolts. Strangely enough when doing some work on the forestay mount, I checked the two bolts and while both were secure through the foot of the mast, I was able to easily undo the nuts and pull both bolts (one at a time) out through the mast implying there was no pressure on them, not sure if that good or not.

As Will says - the mast sits on its base .. and the bolts are there to stop mast stepping out of the frame. Some boats use a wood wedge under the mast for base to stand on.

On previous boats that had Tabernacle - the upright U frame .. I always tightened the nuts so they would not get lost - but not that they put force on the frame. Use of a smaller diameter than the frames hole ? TBH - don't see the point of that as long as the bolt used is correct and fits properly.

If the frame is what I think it is ... you can remove the bottom bolt and then once stays sorted - pivot the mast down on the top bolt.

 

[oldmanofthehills]

You can of course get a prop re-pitched. It was a lot less expensive than I was expecting when I did mine.

If the engine gets near max revs, which will be near 4000 rpm for a marine diesel the boat is not seriously over propped

Unfortunately the engine issues are almost certainly something else, and I think we may all have got side tracked into prop discussions. Useful for the OP to know about but not the presenting isssue

 

[Sea Hustler]

@Sea Hustler if you were in the mood for spending money, a feathering prop might be quite a big improvement for your boat. She'd sail a great deal better, given that she probably has quite a large prop for her size, being a motor sailer.
She might also be better in reverse, as some feathering props can be given a finer pitch in reverse, reducing prop wash and giving somewhat more responsive maneuvering.
But greatly improved sailing performance would be a certainty. Even a small propeller makes a big difference - I had a Sonata with a 4hp outboard and it felt like she was towing a bucket with the motor tilted down.
You could also get the right size and pitch of prop if you were changing it.

LOL... Not sure I am willing to instal a prop that would be worth more than the rest of the boat although it would be nice if I could. I am the essence of 'boating on a budget' Looking back over the past 18 months, I am acutely aware that had I had the finances, I could have had her back in the water last summer. Sadly, that is not the case and I just have to do what I can then wait until the bank manager says I can do the next job.

 

[Sea Hustler]

The gearbox ration is written on the gearbox, the prop outside diameter can be measured ( i might guess 15 or 16 inch) and the pitch should be written on the prop. And you know the hp

So thats all you need to calc prop suitability

Thanks for that info, I will look for the numbers on the gearbox, probably hidden under the blue hammerite at present because I cannot remember seeing any. The prop I can measure next time Im at the boat at low water (just avoid stepping into the mud, it stinks) and I do recall seeing some numbers stamped on the hub of the prop, so I will check that all out,
Thanks.

 

[Sea Hustler]

If the engine gets near max revs, which will be near 4000 rpm for a marine diesel the boat is not seriously over propped

Unfortunately the engine issues are almost certainly something else, and I think we may all have got side tracked into prop discussions. Useful for the OP to know about but not the presenting isssue

Sadly the rev counter is not working and Im pretty sure the last 1/3 of travel on the throttle lever does not do anything to the revs (hence the idea that she may be over propped) I do have a digital IR doohicky which tells me that at what sounds and feels comfortable, she is doing between 16/1700 rpm. I plan to test her at various throttle settings and mark up the Morse control in 1,000s until I can establish why the tacho isn't working. (is it supply from the alternator or just that the gauge sat for 5 years doing nothing). As I say in a later post, I am the true essence of 'boating on a budget' This is my first boat and it is taking a lot of time and every penny i have to slowly bring her back to life again, this means that there are many jobs still to do that I will get to when they reach the top of the list, meanwhile, if it does not stop the engine running, the prop turning, the anchor holding or the sails sailing, it don't get onto the 'do it now list' and will just have to wait.

Fortunately, while I have a certain skill level and can do more than I think I can, this Forum has been so supportive with advice and guidance that I am confident I will eventually get her fully restored and back doing what she does best, which is sailing.....oh hang on, the reason for this post was because she doesn't do that very well at all LOLOLOL

 

[Sea Hustler]

As Will says - the mast sits on its base .. and the bolts are there to stop mast stepping out of the frame. Some boats use a wood wedge under the mast for base to stand on.

On previous boats that had Tabernacle - the upright U frame .. I always tightened the nuts so they would not get lost - but not that they put force on the frame. Use of a smaller diameter than the frames hole ? TBH - don't see the point of that as long as the bolt used is correct and fits properly.

If the frame is what I think it is ... you can remove the bottom bolt and then once stays sorted - pivot the mast down on the top bolt.

Thanks, Yes my mast sits in a U shaped thing which I have always understood is called a tabernacle. I was concerned that the nuts on both bolts as well as the thread ends were showing signs of corrosion which was why I removed them to check but its only surface rust and the main body of both bolts are clean and in good condition so I just put them back, if memory serves, they are M10's

 

[Refueler]

If the engine gets near max revs, which will be near 4000 rpm for a marine diesel the boat is not seriously over propped

Unfortunately the engine issues are almost certainly something else, and I think we may all have got side tracked into prop discussions. Useful for the OP to know about but not the presenting isssue

Once Sea Hustler mentioned removing the 'nut' from the injection pump - believing it to be the bleed screw - I think we may have a reason for the engine putting out fuel into the water .. and the max revs ... Maybe.

I would get that injection pump checked and setup - then try again ...

 

[Refueler]

My 25 ran for over 40yrs with no rev counter ... previous owners and myself - we just set the throttle at a nice sweet engine level ... kept a nice steady 4.5 - 5kts .....

I fitted a Tacho sensor that straps to outside of alternator ... fitted a gauge and bingo - simplest rev counter setup for about 50 quid all in ...
When I tacho'd with my hand held to make sure it read correct ... then went for a sail - I was amazed that I found my guesstimated rpm of 1200 - 1300 was near the fact !!

My 38 has no tacho .. and I have another 50 quid setup ready to fit to that boat ...

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