Is it a viable tactic to use a flurry of blows monk to mass grapple a single target?

Can anyone help illustrate or explain the statistical advantages or disadvantages in using flurry of blows to make multiple grapple attempts against a target in the hopes of overwhelming them and "Pin" them down?

Situational Context:

Once upon a time I had a Flurry of Blows vow of Poverty Monk who was built to be a mobility / single target assassin of sorts on the battlefield. His schtick was to run in with his massive movement speed, overwhelm the target with grapple attempts and either pin or drag the target to a more strategic location. Orignally he was build with "Perfectly" level stats (11's or 13's), with no most of his relevant stats hovering around 15-16 for the majority of his career. Because of the lower attack base I went all in with flurry of blows and two weapon fighting and grapple to give him some kind of role in combat.

I have always wondered, but never been able to articulate or math out a comparison of math'ing out mass attack attempts and grapple attempts VS either raw attacks or an optimized grapple specialist (Max STR, fewer attacks).

So I know we have a few statistical Gu-Ru's in the community and I was wondering if they could help illustrate or compare how a mass grapple monk would compare to a more traditional combat monk.

I also appreciate this this semi-nebulus question may not meet community standards of specificity but I am more than willing to awnser clarifying questions or simplify / the analysis requested. I just have this idea in my head and I'm not quite sure how to articulate the question.

Awnsering comment requests:

The original build was a Mono Classed Human Monk with a point buy method, 13,13,13,11,11,11, Int, Con Wis. Using the Vow of poverty increases I brought up his lower stats first so everything would kinda come out about the same with normal level increases, so around level 12 or 13 he was 14 stat block across the board if I remember correctly. Feat selections was to take the whole "Monk Bonus Feats" selections listed in the PHB under the monk class - so no uber deep dives into feat chains.

The Flurry of blows grapple tactic seemed to be the one reliable combat trick that made him a battlefield contributor. If he managed to pin them down - the monster or creature would have to blow their action economy to escape the grapple - only to have to do it all over again on his next round - with additional attacks / damage if managed to hold his pin - or land his pin early in the flurry chain.

• First instinct, did you have something to let you grapple the big things? Otherwise it seems it'd be a bit limited....
– Alan
Feb 5, 2023 at 4:30
• No I didn't - Occasionally the mage would cast enlarge on me from time to time. But I was just a mass attempt to grapple my way through a potential low enemy roll to incriment to grapple status. I was wondering how much my DM was "Fudging Numbers" or if the character was generally pulling off what he was consistantly doing. Feb 5, 2023 at 4:35
• This is an interesting question, but I’m not sure it can be answered. The primary concern is, what exactly is the competition? Another monk? A fighter? A barbarian? A druid who just uses wild shape? For that matter, there are some questions about your own build, as well—are you a pure monk? Or do you multiclass once you have greater flurry? For that matter, how are ability scores generated—how much Strength are you missing going this route? And the problem is, even if you nail those down, it makes it a much less interesting question—the real interesting bit is “what are the breaking points?” Feb 5, 2023 at 5:42
• But it’s just too many variables that can be adjusted, I think. The combinatorics get unwieldy quickly. Maybe for strict monk-vs-monk we could handle this? But already that’s a much less interesting question, IMO. Maybe monk-vs-barbarian is better... Feb 5, 2023 at 5:43
• Also, it seems like there’s a have-your-cake-and-eat-it-too build of monk/barbarian/ranger, where whirling frenzy gives you an extra attack, and combat style gets you Two-Weapon Fighting and possibly Improved Two-Weapon Fighting without Dexterity, so you can still go for high-Strength (and have more BAB than a pure monk). You miss out on Greater Two-Weapon Fighting, but whirling frenzy probably makes up for that (−2 penalty on all attacks vs. −15 penalty on one). Plus you get pounce, so you can use that movement speed and all those attacks in the same round. Feb 5, 2023 at 5:50

From the start we already have a problem. If you have a 13 Dexterity, you don't have the Two-Weapon Fighting Feat as it requires a Dex 15 so it'll take a while to build up to that (probably level 6 minimum to get the appropriate stat buff and have the feat open). That's even without taking Sacred Vow and Vow of Poverty. Without knowing the level and race of the character, this is going to vary wildly, especially with Vow of Poverty.

That said, let's work from the top. 3.5PHB Grappling section on page 156. Starting a Grapple

If you get multiple attacks, you can attempt to start a grapple multiple times (at successively lower base attack bonus)

So you may initiate a grapple with Flurry's extra attacks Step 1: Attack of Opportunity You mentioned going "all in for grapple", so either you've taken the feat or are level 2+. Let's assume either are the case, because even if we assume the level 6 needed for Two Weapon Fighting, your unarmed defense is ~22 with Vow of Poverty which gives you some reasonable chances of not stopping before we begin. Plus a given character can only make an AoO against you specifically once/round, so the next attempt if you have more left won't be subject.

Step 2: Grab

You make a melee touch attack to grab the target

Using a touch attack will help your odds of making the grab in a super majority of cases.

Step 3: Hold

Make an opposed grapple check as a free action. If you succeed, you and your target are now grappling, and you deal damage to the target as if an with an unarmed strike. If you lose, you fail to start the grapple. You automatically lose an attempt to hold if the target is two or more size categories larger than you are. Once again, your build by this point is going to make things extremely varied. For example, if you took "Touch of Golden Ice" as a bonus feat from your Vow and the target is evil.

This is where your success curve will fall. You essentially need to get a second attack off to get you're first hit's worth of damage, and this becomes a wildly floating target. The target might have a great Escape artist check (if their touch AC was high), or they likely have a better grapple bonus than their touch AC modifier; either gets the benefit of a d20 instead of assuming a 10 (55% chance 1d20 >= 10). We're going to wash out size categories for now, but that's +/-4 per difference. On the plus side, at higher levels you get the highest BAB in this check (but so do they)

If you fail the roll, we're back to start like you missed at step 2, so hey - you have extra attacks to fall back on.

Step 4: Maintain Grapple

To Maintain the grapple for later rounds you must move into the target's space. This movement is free and doesn't count as part of your movement in the round. Moving, as normal, provokes attacks of opportunity from threatening opponents but not your target. If you can't move into your target's space you can't maintain the grapple and must immediately let go of the target.

If You're Grappling

You get an action per attack with BAB, and Flurry specifically states it affects the BAB.

• Activate a magic item (Vow of Poverty says you own none)
• Attack Your Opponent: You attack at -4, and do not get the extra attack from TWF ("You can't attack with two weapons while grappling, even if both are light weapons"). They've lost their Dex bonus to AC if any which may offset the penalty
• Cast a Spell / Retrieve Spell Components (You have no spell slots)
• Damage your opponent: Make opposed grapple check to deal unarmed damage.
• Draw a Light Weapon
• Escape from grapple with opposed Escape Artist or Grapple Check against all grapplers opposing you and move to adjacent space (unopposed if they're unconscious/dead)
• Move half speed, bringing whole group with opposed grapple check as a standard action (so only thing with grapple this round)
• Pin opponent with an opposed grapple (which does more for people who aren't you) for one round
• Use Opponent's Weapon is honestly the best thing that can happen in a grapple when you have a Vow of Poverty as long as it's light. You're not taking ownership of the weapon to use it, and it's likely better than the +1 magic weapon that being unarmed effectively rates with the Vow.

Other than the initial "Grab", all ACs for your target include their armor class, and unless they're using Escape Artist to escape a grapple their armor check penalty doesn't come into play (p122). The characters you'll get the most benefit out of grappling are faster ones that you need to nullify Dex and/or movement with, or spell casters so you limit their choices and force concentration checks. Otherwise you're getting a bigger penalty on your attack rolls and essentially drawing a lot of aggro. You're either taking huge penalties to attack, or allowing them a greater chance to resist your attack where they use their highest BAB to resist versus your current one to strike.

All in all I would rate a purely grapple focused monk in D&D3.5e as highly inefficient but it offers some nice options in extremely specific circumstances

I would be more specific but there's a lot of missing information with the build given.