is 13 hp yanmar too small for 33ft steel yacht?

[Celestialsailor]

Originally Posted by Kanani

I don't think that your "Stopping" problem was due to a lack of HP. That is usually a matter of having a poor prop (Foding, 2 blade etc).

If I were going to have a vessel that was under-powered, I would strongly consider a Maxi-prop (or similar) or at the very least a well pitched 3 blade prop. The prop will make a world of difference on a vessel like that. The critical thing is to be sure that you can get max RPM out of the engine without being able to over-rev the engine while motoring (again....clean bottom....very important). That will give you optimum performance.

Point well taken. It could have been the prop but problem solved anyways. New engine, new prop. I actually opted for a broader bladed 3 blade prop designed for motoring. The folks told me that their experience with my design of boat and all her wetted surface is the boat speed would not be greatly affected by this prop and they seem to be right. I am very happy with the way the boat gets up and goes now and stopping it. I just live with the prop wash while manuvering.

[Southern Star]

I tend to agree with Alan - 4.9 tonnes seems quite light for a 33 foot steel boat. In comparison, my previous 36 foot Cartwright Pilothouse (also in steel) tipped the scales at close to 20,000 lbs. equipped. She had a 50 hp diesel.

I would certainly want to test her out upwind and into a chop.

Brad

[Kanani]

Originally Posted by Celestialsailor

Point well taken. It could have been the prop but problem solved anyways. New engine, new prop. I actually opted for a broader bladed 3 blade prop designed for motoring. The folks told me that their experience with my design of boat and all her wetted surface is the boat speed would not be greatly affected by this prop and they seem to be right. I am very happy with the way the boat gets up and goes now and stopping it. I just live with the prop wash while manuvering.

Soon, you will do more than, "just live with the prop wash while manuvering". Eventually, you will learn to use it for steering and it will become "PART" of you manuvering. It's just a matter of getting used to exactly how the vessel reacts when you put it in forward and reverse.

[dcstrng]

Removed cuz somehow I posted twice... too many thumbs...

[dcstrng]

<weighs 4.9tonnes and is powered by a 13 hp yanmar...>

My little spreadsheet says 18hp is more in the ballpark, at a minimum -- and that assumes fairly cooperative water...

[Catamount]

14 hp 2-cylinder diesel with a folding prop on a 10,000 pound 34-footer (fiberglass) with relatively low wetted surface and a nice clean bottom works for me.

Minimize the effects of adverse tidal currents by timing your trips appropriately. Waves and chop usually mean wind, so you can sail instead of motoring.

But really it all depends on what your expectations are.

[KBT]

Originally Posted by neilrob

Hi to all
Im new to this forum and was wondering if anyone would give me their opinion regarding a yacht that I am looking at.
The yacht is 33 ft, steel construction, weighs 4.9tonnes and is powered by a 13 hp yanmar.
I have sailed on a 25 ft fibreglass yacht with a 8 or 9 hp bmw and the 250 nm voyage was slow going when with out wind at about 4 knts
The broker states that the yacht Im looking at will make 5 to 5.5 knts.
Questions
Does 5 to 5.5 knts seem optimistic?
Is this motor too small for me to do comfortable coastal cruising?
Thanks for helping
neil

Seems very small to me Niel, I would have thought 20-25hp min for a boat that size. Bill.

[hugosalt]

I am under impression 1 hp. for each 500 lbs. total weight boat, tankage, provisions and crew plus correctly sized/ pitched prop. That should be around 20 hp plus min.
Usually these formulas are approx rule of thumb. As stated 13 hp will get you in and out under benign conditions but if the question "is this motor to small for comfortable
coastal cruising? You will find yourself under powered at times.
Hugo

[Alan Wheeler]

Hugo you are correct. Rule of thumb is 1Hp/500lb as minimum. This covers usage such as slipping and basic manourvering.
1.5Hp/500lb is the low end of the OK scale. This covers manourvering in confind marinas, channel transit and other general purpose get you there instances. It will drive refers and generation, but the boat does not have reserves for heavy weather. 3Hp/500lb is the high end of the OK scale. This produces a very capable boat for any situation. It will handle driving the boat with reserve power for refers and generating while still battling into a headwind. So that would equate to ruffly 20Hp, 30Hp and 60Hp respectively.
Going above the 3Hp/500lb is only wasting power.

[Kanani]

All of this info is correct and well and fine, if you are designing a boat. This boat is already equipped with what it has.

I think the OP may be asking, "Is this boat worth re-powering". If that is the question, a lot more information needs to be looked at. If the vessel is in good shape and priced well enough below value to pay for re-powering and that is your desire, then maybe yes.

If the vessel is priced with not much wiggle room and you have big plans for coastal cruising, then maybe no.

The fact is, the vessel is obviously manueverable and if you are going to use it on fair days with a good forecast, it will be safe. Another thing that must be taken into consideration is the skill of the skipper. As has been mentioned before, a lot of people sail boats with no engine at all.

Web Chiles was a freind of mine. It seems to me that "Resorgam" (his Sparkman-Stevens 36) had a very small engine. It didn't matter anyway, he wouldn't start it unless his life depended on it (maybe not even then). If he were to reply to this post it would be with a laugh.

Now that I think about it...........what happened to the OP......maybe the darn thing sank.....