Just bought a “new to me” 19 ft Sea Hunt Bay Boat with a 115 4stoke Yamaha. The hole shot is not good. The RPM’s are about 5400-5500 at WOT so I am thinking that I have the right pitch prop. The boat doesn’t list or porpoise with a reasonably even load. Will a Hydro-foil (fin) substanially help my hole shot and what will I be giving up in return?
Any insight would be appreciated.
I think it depends on the boat. Ive installed five of them on different boats. On one of them, it was fantastic, two were pretty good and the others so so. Cobra Marine makes one out of aluminum that looks better than most and can be painted to match the motor.The self leveling trim tabs work pretty decent at a price less than hydraulic. You might give up a mph or two at WOT but you probably wont notice it much.The boat it worked best on was a 20 foot SeaCraft.Hopefully this helps.
Does your boat not have trim tabs? If it doesn’t, it should. I would go that route and suggest you learn to use them. Tabs are useful for nearly every type boat you will ever fish from.
I may be telling you info you already know. If so, please disregard.
Might want to try and play with some different props. If hole shot is what you are wanting/needing, the correct prop should help you more than anything.
Don’t have any personal experience with your boat, but guessing it may be a little underpowered, therefore difficult to plane when loaded. I have the same motor. That motor should be closer to 6000 rpm at WOT, so you have a little room to play with.
When choosing a prop, I’ll look at a few things depending on boat/application/normal load. Normally I’ll prop my boat for cruising speed at max efficiency for fuel burn.
Plenty of places on web to do the math for you as far as what prop is needed. If you let us know what prop you have now, it would be a good starting point. For any of the equations, you will need your gear ratio- 2.15, slip is normally considered at 10% or .1, and you already know your rpm’s at WOT.
If hole shot is what you want, may want a 4 blade prop. You will lose top end, but gain what you are looking for. Stainless props will normally give a little better performance versus aluminum.
Sorry, but never been a big advocate of the fin. Kinda like fixing a symptom, not the problem. You can find/borrow used props for a test run before buying a new one.
Good Luck.
Have you tried dropping your motor down one or two holes on the bracket so it’s closer to the transom? That should lower your bow and help your hole shot; your trim and tilt should offset that adjustment once you plane out? It won’t cost you anything to try it.
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If you needed to add any sort of device to the rear of your boat, I’d look in to trim tabs first.
Does the motor seem to develop it’s power properly, or could it be the motor itself struggling to reach WOT?
“Sire, it belongs in truth to the Church of God, in whose name I speak, to endure blows and not to inflict them. But it will also please your Majesty to remember that she is an anvil that has worn out many hammers.”…Theodore Beza
It is a 115 .They sell the boat rigged for the best price.Most 19 footers need a 150.Live with it or get a 150.
Stonoman
DISCLAIMER: I am probably the least experienced person on this site as far as experimenting with different props goes.
That being said, a 3 blade prop of the correct pitch may get you where you want as far as RPM at max load (WOT), but you may find that a 4 blade prop (with the appropriate pitch) can provide the same top end with a slightly better hole shot. It’s not the cheapest route, but it’s less expensive than buying a new engine and could make a huge difference. Even going with another 3 blade prop with a different blade profile but similar pitch would probably made a difference.
Just food for thought.
edit: typo
I’m not sure of the exact specs of your boat, but I found this data performance sheet on a vessel similar to yours. This isn’t an answer to your question per se, but it might be worth a look.
As you can see, when you ask a question on this site yourre going to get a lot of different opinions, which is a good thing. A bigger motor ? Absolutely, theres no substitute for horsepower as they say. As stated, they sell a lot of boats with just " adequate " power because of the price and also because of the weight of new four stroke engines are so much heavier than than the older two stroke motors. A good prop shop ( Skips still around ? ) could probably alter your prop and help some or make better suggestions than most people.Better to stay local in my opinion than save a couple of bucks on the internet.
Ive owned many boats and currently have four, one with hydraulic tabs, one with Smart Tabs, one with a Fin and one with no additions.I personally have no problem with " bolt on " parts whether they are trim tabs or Fins to personalize a boat to my preference. More than likely you are going to have to do more than one thing to get your boat to perform like you want it to. Some suggestions and some of the things Ive done in the past are as follows.
Shift the fuel tank forward if possible.You may have to cut the foam if it is a foamed in tank. Even a few inches can make a difference.
Move the center console and seating forward.
Tabs, whether hydraulic,electric or " smart tabs". I personally would not hesitate to try a fin either. All of them have pros and cons, price, maintenance etc.
I’ve had a lot of experience with them. They will often help a flat bottom boat, especially those that are light in weight and marginal to heavy in HP. The best way I can describe it is they help the boat stay attached to the water, rather than jumping all over as light boats tend to do.
They will not make up for a lack of HP and will not do much good for most V bottom hulls, but they will on some. They can help to keep the bow down, stop excessive porpoising at planing speed, give you more trim control, and plane out at a lower speed, but they will also cost a few mph in top end speed because of the drag.
In short, if you have a flat bottom skiff that is fairly fast, they can help a lot. With a 19’ V bottom Sea Hunt probably not so much. Better to go with trim tabs.
Capt. Larry Teuton
Cracker Built Custom Boats
“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
quote:
The RPM's are about 5400-5500 at WOT so I am thinking that I have the right pitch prop. The boat doesn't list or porpoise with a reasonably even load. Will a Hydro-foil (fin) substanially help my hole shot and what will I be giving up in return
I should have just answered the question, instead of the replies 
quote:
Will a Hydro-foil (fin) substanially help my hole shot
No
quote:
what will I be giving up in return
Top end speed.
They help small, light, flat bottom boats much more than they help boats like yours. It needs trim tabs for best results. Plus the right prop and the right motor height.
Capt. Larry Teuton
Cracker Built Custom Boats
“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
I would respectfully disagree,at least in my experience. I took the foil off my Carolina Skiff and put tabs on it and they worked better on this particular boat. My SeaCraft ( V hull )would plane in 15 feet and run 68+ mph. Admittedly over powered but until I made the changes it was a dog out of the hole. Every boat/ motor combination is different.
Thanks for all of the input guys…I think I am at least going to try the foil first. I only need to gain a little in hole shot to be satisfied. If it doesn’t work I will take it off and am only out about $100. Trim Tabs and a different prop would be next. A horsepower upgrade is definitely not in the cards…The hole shot probably isn’t as bad as I think because I am used to a 17 War Eagle with a 70 on it. I just don’t like the bow in the air so long when I am trying to plane out.
quote:
. Every boat/ motor combination is different.
Agree. Trial and error are what they take. You can make serious improvements with prop changes, engine height and foils, but I’ve never seen a boat that didn’t perform better with trim tabs than without.
Capt. Larry Teuton
Cracker Built Custom Boats
“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
you do NOT have the correct prop on that motor
the correct prop should see 6000rpms WOT trim out with average load
unless your motor is ventilating, do NOT lower the motor on the transom
it will create more drag, and possibly cause the boat to porpoise.